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Cat Calorie Calculator

Ready to calculate
DER = 70·W^0.75 × coef.
AAFP / NRC standard.
7 condition presets.
100% Free.
No Data Stored.

How it Works

01Weigh Your Cat

Body weight in kg or lb. Use the IDEAL weight for weight-loss mode; current weight for everything else.

02Pick a Condition

Neutered adult (1.2× RER), intact (1.4×), weight loss (0.8×), kitten (2.0-2.5×), or set custom coefficient.

03Apply DER = 70 × W^0.75 × coef

RER from allometric scaling × maintenance coefficient = Daily Energy Requirement (kcal/day).

04Translate to Food Servings

Calculator converts to grams of dry kibble (~400 kcal/100 g) and wet food (~85 kcal/100 g) for portion planning.

What is a Cat Calorie Calculator?

Feeding the right amount of food is the single most important daily decision in cat care — overfeed and your cat develops obesity (estimated 50-60% of US house cats are overweight or obese), underfeed and you risk weight loss, hepatic lipidosis (a serious feline-specific liver condition), or growth failure in kittens. The standard formulation used by the AAFP (American Association of Feline Practitioners) and NRC (National Research Council) for daily caloric requirement is DER (Daily Energy Requirement) = RER (Resting Energy Requirement) × maintenance coefficient, where RER (kcal/day) = 70 × weight_kg^0.75 follows the standard mammalian allometric scaling and the maintenance coefficient depends on life stage and physiological condition.

Our Cat Calorie Calculator implements the full AAFP / NRC framework with 7 condition presets: Neutered adult (1.2× RER, the largest population — most commercial adult-maintenance cat foods are formulated to this DER); Non-neutered adult (1.4×, intact cats have ~15-20% higher demand from reproductive hormones); Weight loss (0.8× × IDEAL body weight, not current); Weight gain (1.4× × current weight, for underweight cats / recovery); 0-4 month kitten (2.5×, highest energy demand of any feline life stage); 4 months to adult (2.0×, slowing growth); Custom coefficient for special situations (pregnancy 2.0-2.5×, late lactation 3.5×, senior 1.1×, recovery from major illness 1.5×). Multi-unit weight input (kg or lb).

Output: Daily Energy Requirement in kcal/day and kJ/day; RER for reference; per-meal portions for 3-meal scheduled feeding; food-equivalent translations to grams of dry kibble (~400 kcal/100 g) and wet food (~85 kcal/100 g) for portion planning. Smart warnings flag overweight cats (> 7 kg as adult — likely BCS 7-9), suspiciously low weights (< 2 kg adult), and kitten-coefficient mismatches. Designed for cat owners trying to feed correctly, veterinary technicians counseling clients on weight management, foster and rescue volunteers documenting nutrition for kittens and rehab cats, breed-specific cat communities (Maine Coon, Bengal, Persian) calibrating diet, and pet-food consultants selecting brands and portion sizes — runs entirely in your browser, no account, no data stored.

Pro Tip: Pair this with our Cat Age Calculator for life-stage classification, our Cat Quality of Life Calculator for end-of-life decision support, our Cat Chocolate Toxicity Calculator for accidental-ingestion triage, or our Benadryl Dosage Calculator for allergy first-aid.

How to Use the Cat Calorie Calculator?

Weigh Your Cat: in kg or lb. Best practice: use a baby scale or dedicated pet scale for ±10 g accuracy. Alternative: weigh yourself, then weigh yourself holding the cat, subtract — accurate to ±0.1 kg. For overweight cats, use IDEAL body weight (not current) for weight-loss mode; ask your vet for the target.
Pick a Condition Preset: 7 options matching life stage and physiological status. Neutered adult (1.2× RER): spayed/neutered, standard adult cat — the most common case. Non-neutered adult (1.4×): intact adults; reduces to 1.2× after spay/neuter. Weight loss (0.8×): calorie-restricted feeding using IDEAL weight; 1-2% loss/week max. Weight gain (1.4×): for underweight cats. Kitten 0-4 mo (2.5×): highest demand, free-feed kitten formula. Kitten 4 mo-adult (2.0×): still growing but slower. Custom: set your own.
Apply DER = (70 × W^0.75) × Coefficient: the calculator computes RER first (70 × weight in kg to the 0.75 power), then multiplies by your selected coefficient. Worked example: 4.5 kg neutered adult cat: RER = 70 × 4.5^0.75 = 70 × 3.09 = 217 kcal/day; DER = 217 × 1.2 = 260 kcal/day.
Read DER in kcal/day: the total daily calorie target. The calculator also outputs per-meal portions for 3-meal scheduled feeding (recommended for adults; free-feed kittens) and food-equivalent translations.
Check Food-Label kcal Per Serving: dry kibble typically 400 kcal/100 g (varies 350-500); wet food 85 kcal/100 g (varies 70-110); single-serve pouches/cans 75-95 kcal each. Always check YOUR specific food — values vary 30-50% across brands. The calculator gives generic estimates as a starting point.
Adjust Based on Body Condition Score (BCS, 1-9 scale): ideal is 4-5 (ribs easily palpable but not visible; visible waist from above; abdominal tuck from side). Reassess monthly. If BCS > 5, reduce feeding 10%; if < 4, increase 10%; if BCS > 7, switch to weight-loss mode using ideal weight.
For Special Cases — Use Custom Coefficient: Pregnancy: 2.0× early (first 2 weeks), 2.5× late (last 5 weeks). Lactation: 2.5-3.5× depending on litter size (more kittens = more demand). Senior cats > 11 yr: 1.1× for typical activity decrease. Hyperthyroid cats: 1.5-2.0× until thyroid is treated. Recovery from major illness: 1.5×. Consult your veterinarian for cat-specific targets.

How is cat calorie need calculated?

Cat caloric requirements follow the standard mammalian allometric scaling — Resting Energy Requirement scales as weight^0.75 (the metabolic-rate exponent identified by Kleiber 1932 and confirmed across ~100,000 species). The AAFP / NRC framework adds a maintenance coefficient that captures life-stage and physiological-condition adjustments.

References: AAFP Nutritional Assessment Guidelines (2010, 2021 update); NRC Nutrient Requirements of Dogs and Cats (2006); WSAVA Global Nutrition Guidelines; Cornell Feline Health Center; Plumb's Veterinary Drug Handbook.

Core Formulas

Resting Energy Requirement (RER, kcal/day) = 70 × weight_kg^0.75

Daily Energy Requirement (DER, kcal/day) = RER × maintenance coefficient

Where weight_kg is the cat's body weight in kilograms and the maintenance coefficient depends on life stage and physiological condition.

Maintenance Coefficients (AAFP / NRC)

  • Neutered adult (most common): 1.2 × RER. Standard for spayed/neutered adult cats; most commercial adult-maintenance foods formulated to this DER.
  • Non-neutered (intact) adult: 1.4 × RER. ~15-20% higher demand from reproductive hormones and roaming behavior.
  • Weight loss: 0.8 × RER × IDEAL weight (not current). Aim for 1-2% body-weight loss per week max.
  • Weight gain: 1.4 × RER × current weight. For underweight, recovering, or growing animals.
  • Kitten 0-4 months: 2.5 × RER. Highest demand of any life stage — rapid growth + organogenesis.
  • Kitten 4 months to adult: 2.0 × RER. Slowing growth; transition to adult food at 12 months.
  • Senior (> 11 years): 1.1 × RER. Slight decrease for reduced activity (use 1.0× for arthritic / sedentary).
  • Pregnancy: 2.0× (first 2 weeks) → 2.5× (last 5 weeks).
  • Lactation: 2.5-3.5× depending on litter size.
  • Recovery from major illness or surgery: 1.5×.
  • Hyperthyroidism (untreated): 1.5-2.0× until thyroid is treated.

Worked Example — Neutered Adult Cat

4.5 kg (10 lb) neutered adult cat at ideal body condition.

  • RER = 70 × 4.5^0.75 = 70 × 3.090 = 216.3 kcal/day.
  • DER = 216.3 × 1.2 = 260 kcal/day.
  • Per meal (3 meals/day): 87 kcal each.
  • Dry kibble equivalent (~400 kcal/100 g): 65 g/day = ~3/4 cup.
  • Wet food equivalent (~85 kcal/100 g): 305 g/day = ~3 standard 3-oz pouches.

Worked Example — Growing Kitten

1.2 kg, 3-month-old kitten.

  • RER = 70 × 1.2^0.75 = 70 × 1.146 = 80.2 kcal/day.
  • DER = 80.2 × 2.5 = 201 kcal/day.
  • Note the very high coefficient — a kitten this size eats nearly as much as an adult cat 4× its weight!
  • Free-feed kitten-formula food (higher protein and calorie density than adult food); weigh weekly to track 50-100 g/week growth.

Worked Example — Weight-Loss Plan

Currently 6.5 kg (severely overweight, BCS 8/9); ideal weight 5.0 kg.

  • Use IDEAL weight (5.0 kg), not current.
  • RER (ideal) = 70 × 5.0^0.75 = 70 × 3.344 = 234 kcal/day.
  • DER (weight loss) = 234 × 0.8 = 187 kcal/day.
  • Target weight loss: 1-2% per week × 6.5 kg = 65-130 g/week. Achieving 5.0 kg takes 12-25 weeks (3-6 months).
  • Critical: faster weight loss risks hepatic lipidosis (mortality 30-100% if untreated). Combine restricted feeding with weight-management diet (high-protein, moderate-fat, prescription if available) and increased play/activity.

Reference DER for Common Cat Sizes (Neutered Adult, 1.2× RER)

  • 2 kg (small / undersized): 141 kcal/day.
  • 3 kg (small adult): 191 kcal/day.
  • 4 kg (lean adult, average): 238 kcal/day.
  • 4.5 kg (typical adult): 260 kcal/day.
  • 5 kg (medium adult): 281 kcal/day.
  • 6 kg (large adult, near overweight): 322 kcal/day.
  • 7 kg (overweight or large breed): 361 kcal/day.
  • 8 kg (Maine Coon-sized OR overweight): 399 kcal/day.
  • 10 kg (very large or obese): 472 kcal/day.
  • 12 kg (exceptional / morbidly obese): 543 kcal/day.
Real-World Example

Worked Example — Designing a Weight-Loss Plan for an Overweight Cat

Scenario: Owner brings in a 9-year-old neutered male DSH cat. Current weight 7.0 kg (15.4 lb), BCS 8/9 (significantly overweight; ribs hard to palpate, no visible waist, large abdominal pad). Vet has set ideal weight target of 5.5 kg.

Step 1 — Compute Maintenance DER at Ideal Weight.

  • RER (ideal weight 5.5 kg) = 70 × 5.5^0.75 = 70 × 3.59 = 251 kcal/day.
  • DER (weight-loss mode 0.8× × ideal): 251 × 0.8 = 201 kcal/day.
  • Compare to current maintenance (7.0 kg × 1.2× RER = 433 kcal/day) — about 54% reduction.

Step 2 — Plan Weekly Weight Loss.

  • Target: 1-2% body weight per week. 7.0 kg × 1.5% = 105 g/week = 0.105 kg/week.
  • To lose 1.5 kg (7.0 → 5.5 kg) at 105 g/week: about 14 weeks = 3.5 months.
  • Build in monthly weight checks; adjust feeding ±10% if rate is too fast or too slow.

Step 3 — Choose a Diet.

  • Recommended: prescription weight-management food (Hill's w/d, Royal Canin Satiety, Purina OM) — engineered for high satiety at low calorie density.
  • Why prescription: regular adult food at 201 kcal/day = ~50 g of dry kibble (less than 1/3 cup) — many cats won't feel satisfied; food-aversion / aggressive begging is common.
  • Prescription weight-management foods are ~25-30% lower kcal/cup than regular adult food, allowing the same satisfaction at lower calorie intake.
  • Wet vs dry: wet food is more filling and helps urinary-tract health; mix wet + dry for satiety + cost balance.

Step 4 — Translate to Daily Portions.

  • If using prescription dry kibble at 350 kcal/100 g: 201 / 3.50 = 57 g/day, divided into 3 meals = 19 g/meal (~2 tbsp).
  • If using wet weight-management at 75 kcal/100 g: 201 / 0.75 = 268 g/day = ~3 small (3-oz) pouches.
  • Mixed feeding: 30 g dry (~105 kcal) + 1 wet pouch (95 kcal) = 200 kcal/day in 2-3 meal sessions.

Step 5 — Monitor and Adjust.

  • Weekly: weigh on baby scale; record weight + BCS; target 1-2% loss/week.
  • Monthly: recompute DER at new weight; transition target down toward ideal.
  • If weight loss is too fast (> 2% per week): increase feeding 10%. Critical: rapid weight loss in cats triggers hepatic lipidosis (fatty liver disease) — high mortality if not caught early.
  • If weight loss stalls: reduce feeding 10%, increase play / activity; consider veterinary nutritionist consultation.
  • Red flags requiring immediate vet visit: sudden food refusal, vomiting, lethargy, jaundice (yellow gums/eyes/skin) — symptoms of hepatic lipidosis.

Who Should Use the Cat Calorie Calculator?

1
Compute the right daily portion for your cat's weight and life stage. Adjust monthly based on body condition score; aim for ideal BCS 4-5/9.
2
Standard tool for vet techs and nutritionists explaining DER to clients; hand-out the kcal/day target, then translate to portions of the client's specific food.
3
Compute restricted DER using IDEAL weight and 0.8× coefficient; plan 1-2% weekly loss; monitor for hepatic lipidosis warning signs.
4
High coefficient (2.5× for 0-4 months, 2.0× for 4-12 months) for active growth phase. Free-feed kitten formula; weigh weekly to confirm 50-100 g/week growth.
5
Document daily caloric intake for foster cats; especially important for underweight stray rehab cases (use weight-gain coefficient with current weight).
6
Custom coefficient: 2.0× early pregnancy, 2.5× late pregnancy, 2.5-3.5× lactation depending on litter size. Free-feed high-quality kitten food during gestation and nursing.
7
Senior cats (11+ years) often have decreased activity (use 1.0-1.1× custom coef) but can also have hyperthyroidism (1.5-2.0× until treated) or chronic kidney disease (decreased appetite). Frequent reassessment essential.

Technical Reference

Allometric Scaling — Why W^0.75? Max Kleiber's 1932 paper "Body size and metabolism" established that basal metabolic rate (BMR) scales as body mass to the 3/4 power (= 0.75) across mammals from mice to elephants. The 0.75 exponent (later confirmed via West-Brown-Enquist fractal-network theory in 1997) is the universal scaling for organism metabolism — smaller animals have higher per-kg metabolism, larger animals have lower per-kg metabolism, but total metabolism follows mass^0.75. The cat formula RER = 70 × W^0.75 uses 70 as the empirical mammal-specific constant (the "Kleiber constant" for kcal/day).

RER vs DER — Definitions. RER (Resting Energy Requirement): the calories needed to maintain basal metabolism in a thermoneutral environment, no exercise, no growth, no reproduction — essentially "if the cat just lay still all day in a comfortable room." DER (Daily Energy Requirement): RER × coefficient that accounts for activity, life stage, and physiological condition. The DER is what you actually feed.

Maintenance Coefficients — Detailed Reference (AAFP / NRC 2006).

  • Adult cats: Neutered 1.2; intact 1.4; senior 1.0-1.1 (decreased activity).
  • Weight loss: 0.8 × RER calculated from IDEAL weight. Some references use 1.0 × RER calculated from current weight (equivalent for ~25% overweight cat).
  • Weight gain: 1.4 × RER calculated from current weight; reassess every 2 weeks.
  • Growth: Kittens 0-4 months 2.5×; 4 months to adult 2.0×; 6 months to adult 1.6×.
  • Pregnancy: Weeks 1-2: RER × 2.0; Weeks 3-6: RER × 2.25; Last 2 weeks: RER × 2.5.
  • Lactation: Variable: 1.5-3.5 × RER depending on litter size; allow free-feeding queen + her nursing kittens.
  • Hospitalized critical care: 1.0 × RER initially (sick cats often anorexic); increase as recovery permits.
  • Hyperthyroid (untreated): 1.5-2.0 × RER (T4 elevation drives metabolism); normalizes after methimazole or I-131 treatment.
  • Diabetes mellitus: typically use weight-loss coefficient if obese (most diabetic cats are); weight-management food (high-protein, low-carb).

Body Condition Scoring (BCS, 1-9 Scale). The standard veterinary assessment for body fat:

  • BCS 1-3 (underweight): ribs visible from a distance; no fat pad; severe abdominal tuck.
  • BCS 4-5 (ideal): ribs easily palpated with light pressure; minimal fat pad; visible waist from above; visible abdominal tuck from side.
  • BCS 6-7 (overweight): ribs palpable with moderate pressure; moderate abdominal fat pad; waist barely visible; minimal tuck.
  • BCS 8-9 (obese): ribs hard to palpate; large fat pad; no waist; no tuck; obvious abdominal sag.
  • Each BCS unit above ideal corresponds to ~10-15% above ideal body weight. Use weight-loss mode for BCS ≥ 7.

Hepatic Lipidosis — The Critical Risk in Rapid Weight Loss. Feline hepatic lipidosis (also called "fatty liver disease") is triggered by sudden food refusal or rapid weight loss in cats — particularly obese cats. Mechanism: cats mobilize body fat to the liver faster than the liver can process it; triglycerides accumulate in hepatocytes, causing liver failure. Symptoms: anorexia, vomiting, jaundice, lethargy. Mortality: 30% with treatment, near 100% if untreated. Treatment: aggressive nutritional support (often via esophagostomy or PEG feeding tube) to reverse fat mobilization. Prevention: never let an obese cat go > 24-48 hours without eating; weight loss target 1-2% body weight per week max; prescription weight-management diet under veterinary supervision.

Feeding Frequency & Method.

  • Kittens: free-feed kitten food (always available); growth period needs constant access to fuel.
  • Adult cats: portion-controlled, 2-3 meals/day (morning, evening + optional midday). Discourage free-feeding for adults — leads to overeating and obesity.
  • Working cats / outdoor cats: can free-feed if well-exercised and not overweight.
  • Multi-cat households: separate feeding stations; one cat can dominate communal bowls. Consider microchip-activated feeders for diet-controlled individuals.
  • Slow-feeders / puzzle bowls: useful for cats who eat too fast or vomit; engages natural hunting instincts.

Food Calorie Densities (Generic Reference, Always Check Specific Label).

  • Dry adult kibble: 350-500 kcal/100 g (3500-5000 kcal/kg); ~3 kcal/g. 1 cup ≈ 100-120 g ≈ 350-450 kcal.
  • Dry kitten kibble: 400-450 kcal/100 g (higher than adult).
  • Wet pâté (canned): 80-120 kcal/100 g; ~1 kcal/g. 3-oz pouch (85 g) ≈ 70-100 kcal.
  • Wet chunks-in-gravy: 60-90 kcal/100 g (lower than pâté due to water content).
  • Treats (dry crunchy): 3-5 kcal each — typical small treat. Limit treats to 10% of daily calories.
  • Always check the AAFCO statement on the label for "complete and balanced" certification at the appropriate life stage.

Limitations and Cautions. The AAFP / NRC formula is a population-average estimate; individual variation is ±20%. Re-evaluate every 2-4 weeks based on body condition; adjust feeding ±10% per week. Sick, pregnant, lactating, or geriatric cats warrant a veterinarian-set target rather than a calculator estimate. Brand-specific kcal values vary 30-50% — always check YOUR cat's food label. Treats and table scraps add up fast: limit to 10% of daily calories; one Greenies treat ≈ 1.5 kcal; one Temptations ≈ 2 kcal — adds up quickly when given multiple times per day. References: AAFP Nutritional Assessment Guidelines (2010, updated 2021); NRC Nutrient Requirements of Dogs and Cats (2006); WSAVA Global Nutrition Guidelines; Cornell Feline Health Center; Plumb's Veterinary Drug Handbook.

Conclusion

Daily caloric needs for cats are set by the AAFP / NRC formulation: DER = RER × maintenance coefficient, where RER (kcal/day) = 70 × weight_kg^0.75 and the coefficient ranges from 0.8 (weight loss) to 3.5 (peak lactation). For the most common case — a healthy spayed/neutered adult cat — the coefficient is 1.2× RER, giving roughly 240-280 kcal/day for typical 4-5 kg cats. Always check the kcal-per-serving on YOUR specific food label (varies 30-50% across brands) and adjust ±10% per week based on body-condition-score trend.

Three reminders: (1) The DER is a STARTING ESTIMATE — actual cat metabolism varies ±20% individual-to-individual. Monitor body condition score (BCS, 1-9 scale; ideal 4-5) monthly and adjust feeding accordingly. (2) Weight loss must be SLOW (1-2% body weight per week max) — faster loss triggers hepatic lipidosis, a serious feline-specific liver condition with high mortality. (3) Feline obesity is the most common nutritional disorder in indoor cats — estimated 50-60% of US house cats are overweight or obese, increasing risk of diabetes, arthritis, urinary disease, and shortened lifespan by 1-2 years on average. Use this calculator as a tool to set a daily target and stick to it.

Frequently Asked Questions

What is the Cat Calorie Calculator?
It implements the standard AAFP / NRC Daily Energy Requirement (DER) formula for cats: DER = RER × maintenance coefficient, where RER (Resting Energy Requirement) = 70 × weight_kg^0.75. 7 condition presets: neutered adult (1.2× RER), intact (1.4×), weight loss (0.8× × ideal weight), weight gain (1.4×), kitten 0-4 mo (2.5×), kitten 4 mo-adult (2.0×), or custom. Output: kcal/day plus food-equivalent translations (grams of dry kibble or wet food).

Pro Tip: Pair this with our Cat Age Calculator.

How many calories does a cat need per day?
Typical adult neutered cat needs about 200-280 kcal/day for a healthy 4-5 kg body weight. Math: RER = 70 × W^0.75; DER = RER × 1.2 (for neutered adult). Reference values: 3 kg cat → 191 kcal/day; 4 kg → 238; 4.5 kg → 260; 5 kg → 281; 6 kg → 322; 7 kg → 361. Kittens need much more per kg of body weight (2.5× coefficient): a 1 kg kitten needs ~175 kcal/day, nearly as much as a 3 kg adult. Always check the kcal-per-cup or per-can on YOUR food label — values vary 30-50% across brands.
What's the formula for cat caloric needs?
RER (kcal/day) = 70 × weight_kg^0.75 (resting energy requirement, mammalian allometric scaling). DER (kcal/day) = RER × coefficient (daily energy requirement, with coefficient adjusted for life stage). Coefficients: neutered adult 1.2; intact adult 1.4; weight loss 0.8 × ideal weight; weight gain 1.4; kitten 0-4 mo 2.5; kitten 4 mo-adult 2.0; pregnant 2.0-2.5; lactating 2.5-3.5; senior 1.1.
Why is the formula 70 × W^0.75?
Allometric scaling — Kleiber's law (1932). Max Kleiber discovered that basal metabolic rate scales as mass^0.75 across all mammals from mice to elephants — confirmed later by West-Brown-Enquist fractal-network theory (1997). The exponent 0.75 reflects how vascular and metabolic networks scale geometrically with body size. The 70 kcal·day⁻¹·kg⁻⁰·⁷⁵ constant is the empirical mammalian average. Practical implication: a 5 kg cat doesn't need 5× the calories of a 1 kg cat — the actual ratio is 5^0.75 = 3.3× because larger animals have proportionally lower per-kg metabolism.
How much should I feed my neutered adult cat?
For a typical 4-5 kg neutered adult cat: 240-280 kcal/day. Use coefficient 1.2× RER. Math for 4.5 kg: RER = 70 × 4.5^0.75 = 216 kcal/day; DER = 216 × 1.2 = 260 kcal/day. Translate to portions: typical dry kibble (400 kcal/100 g) = 65 g/day = ~3/4 cup; typical wet food (85 kcal/100 g) = ~3 small (3-oz) pouches/day. Adjust ±10% per week based on body condition score (BCS, target 4-5/9).
How do I know if my cat is overweight?
Use the Body Condition Score (BCS, 1-9 scale). Ideal (4-5): ribs easily palpable with light pressure; visible waist from above; abdominal tuck from side; minimal fat pad. Overweight (6-7): ribs palpable with moderate pressure; visible fat pad; waist barely visible; minimal tuck. Obese (8-9): ribs hard to palpate; large fat pad; no waist; no abdominal tuck. Each BCS unit above ideal ≈ 10-15% above ideal weight. A 6 kg cat at BCS 8 (obese) has ideal weight ~4.5 kg. Use weight-loss mode (0.8× × ideal weight) for BCS ≥ 7.
How do I help my cat lose weight safely?
Slow and supervised. (1) Use IDEAL weight (not current) for the calorie calculation. Coefficient 0.8× × RER(ideal). (2) Target 1-2% body weight loss per week max — for a 6 kg cat, 60-120 g/week. (3) Use a weight-management diet (Hill's w/d, Royal Canin Satiety, Purina OM) — engineered for high satiety at low calorie density. (4) Increase activity — interactive play 10-20 min twice daily; food-puzzle toys. (5) Monthly weight checks; adjust feeding ±10%. Critical safety: faster weight loss triggers hepatic lipidosis (fatty liver disease) — high mortality. Never let an obese cat go > 24-48 hours without eating.
How much should I feed a kitten?
Kittens have 2-2.5× the per-kg calorie requirement of adults. Coefficient: 2.5× RER for 0-4 months; 2.0× for 4-12 months. Typical 1.5 kg, 4-month-old kitten: RER = 70 × 1.5^0.75 = 95 kcal/day; DER = 95 × 2.5 = 238 kcal/day — the same as a 4 kg adult cat at 1.2× coefficient! Free-feed kitten formula (always available, replenished as eaten); kittens self-regulate intake well. Weigh weekly to track 50-100 g/week growth target. Transition to adult food gradually over 1-2 weeks at 12 months of age.
What's the difference between RER and DER?
RER (Resting Energy Requirement) = calories needed for basal metabolism only — no activity, no growth, no reproduction. RER = 70 × weight_kg^0.75. Like a basal metabolic rate. DER (Daily Energy Requirement) = RER × maintenance coefficient — includes activity, life stage, condition. DER is what you actually feed. Ratio: for typical neutered adult cat, DER = 1.2 × RER, so DER is 20% higher than RER. For kittens DER = 2-2.5 × RER.
What's hepatic lipidosis and why does it matter for weight loss?
Hepatic lipidosis (fatty liver disease) is a feline-specific condition triggered by sudden food refusal or rapid weight loss in cats — particularly obese cats. Mechanism: cats mobilize body fat faster than the liver can process it; triglycerides accumulate in hepatocytes, causing liver failure. Symptoms: anorexia (won't eat at all), vomiting, jaundice (yellow skin / gums / eyes), lethargy. Mortality 30% with treatment, ~100% if untreated. Treatment: aggressive nutritional support via feeding tube to reverse fat mobilization. Prevention: never let an obese cat skip meals > 24-48 hours; weight loss target 1-2% per week max; prescription weight-management diet under vet supervision.
Should I free-feed or scheduled-feed my cat?
Depends on age and weight. Kittens (0-12 months): free-feed kitten formula — they need constant fuel for growth and self-regulate well. Adult cats: portion-controlled scheduled feeding (2-3 meals/day) — better weight management; most adults overeat with free-feeding (~70% of free-fed indoor cats become overweight). Working cats / well-exercised cats: can free-feed if not overweight. Multi-cat households: separate feeding stations to prevent dominant cats from eating others' food. Slow-feeders or puzzle bowls useful for cats who eat too fast or who would benefit from environmental enrichment.

Author Spotlight

The ToolsACE Team - ToolsACE.io Team

The ToolsACE Team

Our ToolsACE team built this calculator to compute the <strong>Daily Energy Requirement (DER)</strong> for cats using the standard <strong>AAFP (American Association of Feline Practitioners) / NRC (National Research Council)</strong> formulation. The defining identity is <strong>DER = RER × maintenance coefficient</strong>, where the Resting Energy Requirement (RER) is given by the allometric formula <strong>RER (kcal/day) = 70 × weight_kg^0.75</strong> and the maintenance coefficient depends on life stage and physiological condition. <strong>7 preset conditions:</strong> neutered adult (1.2× RER, the largest population), non-neutered adult (1.4×), weight loss (0.8× × ideal weight), weight gain (1.4× × current weight), 0-4 month old kitten (2.5×), 4 months kitten to adult (2.0×), and custom coefficient for special situations (pregnancy 2.0-2.5×, late lactation 3.5×, senior 1.1×, recovery 1.5×). Output: DER in kcal/day and kJ/day, RER for reference, per-meal portions for 3-meal scheduled feeding, and food-equivalent translations to grams of dry kibble (~400 kcal/100 g) and wet food (~85 kcal/100 g) for portion planning.

AAFP (American Association of Feline Practitioners) Nutritional Assessment GuidelinesNRC (National Research Council) Nutrient Requirements of Dogs and Cats (2006)Cornell Feline Health Center reference materials

Disclaimer

The Daily Energy Requirement (DER) is a STARTING ESTIMATE — actual cat metabolism varies ±20% individual-to-individual due to breed, activity level, age, and chronic disease status. Monitor body condition score (BCS, 1-9 scale; ideal 4-5) monthly; adjust feeding ±10% per week. Weight loss must be SLOW (1-2% body weight per week max) — faster loss risks hepatic lipidosis (a serious feline-specific liver condition with 30%+ mortality). Free-feeding kittens; scheduled portion-controlled feeding for adults. Always check kcal/cup or kcal/can on YOUR specific food label — values vary 30-50% across brands. For sick, pregnant, lactating, or geriatric cats, consult a veterinarian for individualized targets. References: AAFP (American Association of Feline Practitioners) Nutritional Assessment Guidelines; NRC (National Research Council) Nutrient Requirements of Dogs and Cats (2006); WSAVA Global Nutrition Guidelines; Cornell Feline Health Center.