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Concrete Calculator

Ready to calculate
3 Shapes.
Instant Yardage.
Bags + Ready-Mix.
100% Free.
Privacy Secure.

How it Works

01Pick Shape

Slab, footing, or circular pour.

02Dimensions

Length × width (slab), length × footing width (footing), or diameter (circle).

03Thickness

Typical 4 in slab, 6 in driveway, 8+ in for heavy loads.

04Bags vs Mix

Cubic yards, weight, bag count, and bulk ready-mix cost.

What is a Concrete Calculator?

The Concrete Calculator answers every critical pour question in one tool: how much is a yard of concrete ($160–$220 delivered), how many bags of concrete in a yard (45 × 80 lb, 60 × 60 lb, 90 × 40 lb), how much does a yard of concrete weigh (~4,050 lb), and how much concrete do I need for slabs, footings, and circular pours.

Three shape modes: Slab (rectangular floor, patio, driveway), Footing (strip footing under walls), Circle (round pad or pier base). Any thickness. Compares bagged premix vs ready-mix delivered cost so you know which wins for your size. Includes 10% waste factor automatically.

100% free, instant, in-browser. Based on standard 150 lb/ft³ normal-weight concrete density and 2025 US retail ready-mix pricing ($180/yd³ national average).

How the Concrete Calculator Works

Step 1 — Pick Shape: Slab (rectangle), Footing (length × footing width × depth), or Circle (round pad).
Step 2 — Enter Dimensions: Length and width in feet for slabs, length + footing width in inches for footings, diameter for circles.
Step 3 — Set Thickness: 4 in for standard residential slab, 6 in for driveway, 8+ in for commercial or heavy loads.
Step 4 — Pick Bag Size: 40, 60, 80, or 90 lb premix bags. Or override ready-mix price with a local quote.
Step 5 — Get Estimate: Volume in ft³ / yd³, weight in lb / tons, bag count, coverage per yard, and bag vs ready-mix cost comparison.

The Concrete Volume Formula

SLAB / CIRCLE:   Volume (ft³) = Area × Thickness (in) ÷ 12 FOOTING (strip):   Volume (ft³) = Length × (Footing Width in ÷ 12) × (Depth in ÷ 12) YARDS = Volume (ft³) × 1.10 (waste) ÷ 27 BAGS  = ceil(Volume × 1.10 ÷ bag yield ft³) WEIGHT = Volume × 150 lb/ft³

Core conversions:

  • 1 cubic yard = 27 cubic feet
  • 1 yd³ concrete weighs 4,050 lb = 2.025 US tons
  • Concrete density = 150 lb/ft³ (normal weight, ACI standard)
  • Bag yields: 40 lb = 0.30 ft³, 60 lb = 0.45 ft³, 80 lb = 0.60 ft³, 90 lb = 0.675 ft³
Real-World Example

Calculation In Practice

Example — 12×20 ft patio slab, 4 inch thick, 80 lb bags:

  • Area = 12 × 20 = 240 ft²
  • Volume = 240 × (4 ÷ 12) = 80 ft³
  • With 10% waste = 88 ft³ = 3.26 yd³
  • Bags (80 lb) = ceil(88 ÷ 0.60) = 147 bags
  • Bag cost: 147 × $6.75 = $992
  • Ready-mix: 3.26 × $180 = $587 (+ delivery fee ~$75 = $662 total) → ready-mix wins
  • Weight: 80 × 150 = 12,000 lb = 6 US tons

Who Should Use This Tool?

1
DIY homeowners pouring patios, driveways, walkways, sheds, and shop floors.
2
Concrete contractors quickly estimating yardage during bid preparation.
3
General contractors cross-checking concrete sub quotes against expected yardage.
4
Handymen and landscapers pricing small pours (mailbox posts, deck piers, garden borders).
5
Property owners and managers budgeting repairs: cracked driveways, replaced walkways, new parking slabs.

Technical Reference

Concrete price per yard (2025 US regional averages):

  • Midwest & South — $155–$175/yd³
  • East Coast — $180–$210/yd³
  • West Coast — $175–$220/yd³
  • Pacific Northwest & Hawaii — $200–$240/yd³
  • National average — $180/yd³ delivered

Concrete weight: normal-weight = 150 lb/ft³ = 4,050 lb/yd³. Lightweight (LWC) = 105–125 lb/ft³. Heavyweight (for radiation shielding) = 200–300 lb/ft³.

Typical slab thicknesses: 3 in walkway · 4 in residential slab / patio · 5–6 in driveway · 6–8 in shed / garage floor · 8–10 in commercial / heavy equipment.

Premix bag yields: 40 lb = 0.30 ft³, 50 lb = 0.375 ft³, 60 lb = 0.45 ft³, 80 lb = 0.60 ft³, 90 lb = 0.675 ft³.

Truck load sizes: Standard concrete mixer 8–11 yd³; "short load" premium ($50–$100) charged below ~3 yd³; full load discounts sometimes apply at 10+ yd³.

Key Takeaways

Concrete is priced per cubic yard. National average: $180/yd³ delivered (2025). Bagged concrete is ~65% more expensive per unit but avoids delivery minimums — break-even is typically 1 yd³ (45 × 80 lb bags).

A cubic yard weighs ~4,050 lb. Concrete trucks carry 8–11 yd³. A 10-yard load runs about $1,800–$2,200 delivered. Always order 10% extra — you cannot "pause" a pour to run to Home Depot for another bag.

Frequently Asked Questions

How much is a yard of concrete?
A cubic yard of ready-mix concrete costs $160–$220 delivered in 2025 US pricing, with $180/yd³ as the national average. Bagged concrete works out to about $300/yd³ equivalent (more expensive per unit but convenient for small jobs under 1 yd³).
What is the concrete price per yard in 2025?
National US average: $180/yd³ delivered. Regional ranges: $155–$175 in the Midwest and South, $180–$210 on the East Coast, $200–$240 in the Pacific Northwest and Hawaii. Most suppliers charge a 1 yd³ minimum.
How much does a yard of concrete weigh?
A cubic yard of concrete weighs about 4,050 lb (150 lb/ft³ × 27 ft³), or approximately 2 tons. Lightweight concrete (105–120 lb/ft³) runs ~2,800–3,240 lb/yd³.
How many bags of concrete in a yard?
60 lb bags: 60 bags per yard. 80 lb bags: 45 bags per yard. 40 lb bags: 90 bags per yard. Convert from ft³: 27 ÷ bag yield. 80 lb bag yields 0.60 ft³, so 27 ÷ 0.60 = 45 bags.
How much does a concrete slab cost?
A typical 4-inch residential slab costs $6–$10 per ft² in materials. A 12×12 ft slab (144 ft²) = ~1.78 yd³ = $320–$430 in concrete cost alone, plus $0.50–$1/ft² for rebar and $1–$2/ft² for base prep and finishing.
How much does a 10-yard truck of concrete cost?
A full 10-yard ready-mix truck load costs roughly $1,800 at $180/yd³ (plus delivery fee $50–$150). Most concrete trucks carry 8–11 yd³ — 10 yd³ is a typical full load for pickup and pour.
How many yards in a truck of concrete?
Standard concrete mixer trucks hold 8–11 cubic yards. 10 yd³ is the most common full load, equivalent to 270 ft³ or about 81,000 lb. Don't order more than one truck can carry for a single continuous pour.
How much does a yard of concrete cover?
Depends on thickness. At 4 in slab: 81 ft². At 6 in slab: 54 ft². At 8 in: 40.5 ft². Formula: 27 ÷ (thickness in feet). Our calculator computes this automatically.
How do I calculate yards of concrete?
Yards = (length × width × thickness in feet) ÷ 27. For a 12×20 slab at 4 in (0.333 ft): 12 × 20 × 0.333 ÷ 27 = 2.96 yd³. Add 10% waste = 3.26 yd³ — order 3.5 yd³ minimum.
Is bagged concrete or ready-mix cheaper?
Ready-mix wins above ~1 yd³ (about 45 × 80 lb bags). Below that, bags are cheaper after delivery fees and minimum charges. Our calculator shows both options side-by-side for your exact project.

Author Spotlight

The ToolsACE Team - ToolsACE.io Team

The ToolsACE Team

Our specialized research and development team at ToolsACE brings together decades of collective experience in concrete estimating, ready-mix pricing references, and high-performance web tools.

Concrete Estimating SpecialistsACI / NRMCA ReferencesSoftware Engineering Team

Disclaimer

Estimates based on typical US pricing and standard 150 lb/ft³ concrete density. Actual pricing varies by region, supplier, delivery distance, PSI spec, and additives. Always confirm pricing with local ready-mix suppliers before ordering.