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Urine Protein-Creatinine Ratio Calculator

Ready to calculate
Clinical Thresholds.
mg/dL · g/L · μmol/L.
Spot Urine — No 24h Coll..
100% Free.
No Data Stored.

How it Works

01Spot Urine Sample

Use a random (spot) sample — no 24-hour collection required

02Enter Lab Values

Urine protein and urine creatinine in your lab's preferred units

03Compute Ratio

UPCR = protein ÷ creatinine × 1000 → mg per g

04Read Category

Normal / Mild / Moderate / Nephrotic-range proteinuria

About the Protein/Creatinine Ratio Calculator

The Protein/Creatinine Ratio (PCR) from a single random urine sample is the standard screen for proteinuria — a key sign of kidney disease, preeclampsia, and other conditions. PCR avoids the inconvenience of 24-hour urine collection while approximating its diagnostic accuracy: random PCR (mg/g) ≈ 24-hour urine protein (mg/day) for most adults.


Enter urine protein and creatinine concentrations in any compatible units. The calculator converts to standardized mg/g (or mg/mmol), classifies according to KDIGO 2012 guidelines, and explains the meaning — normal, mild proteinuria, nephrotic-range, or severely elevated.

How the Calculator Works

Enter urine protein in mg/dL (US) or g/L (international).
Enter urine creatinine in mg/dL or mmol/L.
Apply the formula: PCR = Protein ÷ Creatinine, expressed as mg/g or mg/mmol.
Read KDIGO band: A1 normal · A2 moderately increased · A3 severely increased.
Compare to 24-hour estimate — a random PCR of 1500 mg/g approximates 1500 mg/day urine protein.

The PCR Formula

PCR (mg/g) = Urine Protein (mg/dL) × 1000 ÷ Urine Creatinine (mg/dL)


Or in SI: PCR (mg/mmol) = Protein (mg/L) ÷ Creatinine (mmol/L). Conversion: mg/g = mg/mmol × 8.84.


KDIGO 2012 albuminuria-equivalent bands (rough):
A1 (normal): <30 mg/g · A2: 30–300 · A3 (severely increased): >300 · Nephrotic: >3500 mg/g

Real-World Example

Worked Example

Urine protein 100 mg/dL · creatinine 80 mg/dL:

StepCalculationResult
PCR (mg/g)100 × 1000 ÷ 801250 mg/g
Equivalent 24h≈~1.25 g/day
Band300 < 1250 < 3500A3 — severely increased
Action—Nephrology evaluation indicated

Who Uses It

1
🩺 Nephrologists: Routine proteinuria assessment without 24-h collection burden.
2
👶 Obstetric Care: Preeclampsia screening — random PCR ≥0.3 raises concern.
3
💊 Diabetes Care: Annual screening for diabetic nephropathy.
4
🏥 Hospital Medicine: Inpatient proteinuria evaluation when 24-h collection is impractical.
5
🧪 Lab Coordination: Convert between US and SI unit results.
6
📊 Nephrology Research: KDIGO-band stratification for cohort studies.

Final Thoughts

Random PCR has largely replaced 24-hour urine collection in routine practice — easier for patients, similarly accurate for most clinical decisions. The ToolsACE PCR Calculator handles unit conversions and KDIGO-band classification so you can focus on the clinical interpretation.

Frequently Asked Questions

Why does PCR ≈ 24-hour protein?
Daily creatinine excretion is roughly constant per kg of muscle mass (~1 g/day for an average adult). Dividing protein by creatinine normalizes for urine concentration, and the ratio in mg/g approximates the daily protein excretion in mg.
When is 24-hour collection still preferred?
When precision matters: clinical trials, drug dosing in nephrotic syndrome, or when PCR results don't match clinical picture. PCR has ±15–20% variability vs. true 24-hour protein in most studies.
What's the difference between PCR and ACR?
PCR measures total urine protein (albumin + other proteins). ACR (albumin/creatinine ratio) measures only albumin. ACR is preferred for early diabetic kidney disease screening; PCR is broader and used when total protein matters (e.g., glomerular disease).
What's nephrotic-range proteinuria?
>3500 mg/g (or >3.5 g/24h). Nephrotic syndrome adds: hypoalbuminemia, edema, hyperlipidemia. This is a serious finding requiring prompt nephrology evaluation.
What's a 'normal' PCR?
<150 mg/g is generally considered normal. KDIGO uses <30 mg/g for the A1 (normal) albuminuria-equivalent band, but total-protein PCR runs slightly higher than albumin-only ACR.
Why is preeclampsia threshold 0.3 (300 mg/g)?
ACOG considers PCR ≥0.3 (or 24-h protein ≥300 mg) as significant proteinuria in pregnancy — one of the diagnostic criteria for preeclampsia. Random PCR has been validated against 24-h collection in this setting.
Should the sample be first-morning?
First-morning is preferred (more concentrated, less postural variation), but random samples are acceptable. Avoid samples right after intense exercise — that can cause transient orthostatic proteinuria.
Why do US and SI units differ?
US labs report in mg/dL (protein) and mg/dL (creatinine), giving PCR in mg/g. International labs use mg/L and mmol/L, giving PCR in mg/mmol. The calculator converts between them: mg/g = mg/mmol × 8.84.
Can muscle mass affect PCR?
Yes — very low muscle mass (cachexia, frailty) lowers creatinine excretion, raising PCR even at the same actual protein excretion. PCR slightly overestimates protein in low-muscle individuals; underestimates in muscular ones.
Is my data private?
Yes. The calculator runs in your browser. Your lab values are not stored or transmitted.

Author Spotlight

The ToolsACE Team - ToolsACE.io Team

The ToolsACE Team

Our health tools team implements the standard urine protein-creatinine ratio (UPCR) calculation using KDIGO-aligned proteinuria thresholds — normal, mild, moderate, and nephrotic-range categories used in nephrology and primary care to screen for and monitor kidney disease.

KDIGO Proteinuria ThresholdsNephrology Reference RangesSoftware Engineering Team

Medical Disclaimer

PCR is a screening and monitoring metric. Diagnosis of kidney disease requires comprehensive evaluation (eGFR, urinalysis, history, exam). Discuss elevated PCR with a nephrologist or your primary care provider.