How much concrete do I need for a foundation?

Calculate volume: Length × Width × Depth in feet, then divide by 27 to get cubic yards. A 40×30ft slab 4 inches thick = 40×30×0.333/27 = 14.8 cubic yards. Add footings: perimeter × width × depth / 27.

How much does a concrete foundation cost?

Concrete slab foundation: $4-$7/sqft ($5,000-$15,000). Crawl space: $7-$13/sqft ($8,000-$25,000). Full basement: $10-$25/sqft ($20,000-$75,000). Footings alone: $3-$5 per linear foot.

How to calculate foundation footing?

Footing volume = perimeter × footing width × footing depth ÷ 27. Standard residential footings are 16-24 inches wide and 8-12 inches deep. For a 40×30 house: 140 lf × 1.67ft × 0.67ft ÷ 27 = 5.8 cubic yards.

Foundation Calculator - Concrete, Footings, Rebar & Cost

Slab Foundation Calculator

Calculate concrete volume for a monolithic or floating slab foundation.

Slab Length (ft)

Slab Width (ft)

Slab Thickness (in)

Thickened Edge? (in deep)

Edge Width (in)

Rebar Grid

Waste (%)

Slab Foundation Results

CODE: Minimum 3.5" slab on grade. Thickened edges: 12" deep minimum for frost protection. Use 3,000-4,000 PSI concrete. Place vapor barrier (6-mil poly) under slab. Rebar at mid-depth of slab.

Footing Calculator

Calculate concrete for continuous strip footings or spread footings.

Footing Type

Concrete Strength

Total Length (linear ft)

Footing Width (in)

Footing Depth (in)

Waste Factor (%)

Footing Results

CODE: Residential footings: minimum 12" wide, 6" deep for 1-story, 15" wide for 2-story. Footing must extend below frost line (varies by region: 12"-48"). Bottom of footing on undisturbed soil.

Foundation Wall Calculator

Calculate concrete or CMU blocks for foundation walls (basement, crawl space).

Wall Perimeter (linear ft)

Wall Height (ft)

Wall Thickness (in)

Material

Waste (%)

Foundation Wall Results

WATERPROOFING: Apply waterproof membrane on exterior walls. Install drain tile at footing level. Use dampproofing at minimum. Insulate with rigid foam (R-10 minimum in cold climates).

Foundation Cost Calculator

Estimate total foundation costs including concrete, labor, excavation and materials.

Foundation Area (sq ft)

Foundation Type

Concrete ($/cu yd)

Labor ($/sq ft)

Excavation ($/sq ft)

Permits ($)

Engineering/Survey ($)

Foundation Cost Estimate

FACTORS: Soil conditions (rock adds 50-100%), slope grading, frost depth, waterproofing needs, and local labor rates all affect foundation cost. Always get a soil test ($500-$1,500) before building.

How to Calculate a Concrete Foundation

Our foundation calculator helps you determine concrete volume for any foundation type. For a slab foundation: Length × Width × Thickness (in feet) ÷ 27 = cubic yards. A 40×30ft slab, 4" thick = 40 × 30 × 0.333 ÷ 27 = 14.8 cubic yards. Add thickened edges and footings separately.

Foundation Footing Calculator

For strip footings: Total perimeter × footing width × depth ÷ 27. Standard residential footings are 16-20" wide and 8-12" deep. For a 40×30ft house: 140 lf × (20/12)ft × (8/12)ft ÷ 27 = 5.8 cubic yards. Always extend below frost line.

Foundation Cost Estimator

Foundation costs vary by type: Monolithic slab $4-$7/sqft, crawl space $7-$13/sqft, full basement $10-$25/sqft. A 1,200 sqft slab foundation costs approximately $6,000-$10,000 including excavation, concrete, rebar, and labor.

FAQ

How much concrete for a foundation?+

Slab: Length × Width × Thickness ÷ 27. Footings add ~30-50% more concrete. A 1,200 sqft house typically needs 15-25 cubic yards for slab + footings combined. One truck holds ~10 cubic yards.

How much does a foundation cost?+

Slab: $5,000-$15,000. Crawl space: $8,000-$25,000. Full basement: $20,000-$75,000. Pier: $3,000-$10,000. Costs include excavation, concrete, rebar, forms, labor, and waterproofing.

How deep should a foundation footing be?+

Below frost line (12" in warm climates, 36-48" in cold). Minimum 12" below undisturbed ground. Check local building codes. IRC requires minimum 12" below finished grade in areas without frost.