ICF Calculator

Formula

concreteCuFt = wallArea × (coreThickness / 12)concreteCuYd = ⌈(concreteCuFt / 27) × (1 + waste/100) × 10⌉ / 10blockAreaSqFt = (16/12) × (48/12) = 5.333blocksNeeded = ⌈(wallArea / 5.333) × (1 + waste/100)⌉bags80lb = ⌈concreteCuYd × 27 × 1.667⌉

Parameters

Core thickness

Concrete core inside the ICF: 4" for non-load-bearing, 6" for residential walls, 8–10" for taller / commercial.

Waste %

Cuts, corners, openings. 5–10% for straight walls; up to 15% with complex geometry.

Results

ICF Blocks

Standard 16″ × 48″ blocks (5.33 sq ft of wall face each).

Cubic Yards

Concrete to fill the cores — order ready-mix.

80lb Bags

Bags only practical for very small pours under 1 cu yd.

Example

concreteCuFt = 1,200 × (6/12) = 600 cu ftconcreteCuYd = ⌈(600/27) × 1.05 × 10⌉ / 10 = 23.4 cu ydblockAreaSqFt = (16/12) × (48/12) = 5.333blocksNeeded = ⌈(1,200 / 5.333) × 1.05⌉ = 237 blocksbags80lb = ⌈23.4 × 27 × 1.667⌉ = 1,054 bags

Common Use Cases

• Residential foundation walls
• Above-grade ICF walls
• Storm shelters and safe rooms
• Commercial walls up to 10″ core
• Energy-efficient envelope upgrades

Notes

• ICF wall total thickness = core + ~5″ of EPS foam (2.5″ each side).
• Always cross-check with the manufacturer's block-count chart — block heights vary slightly between brands (some 16″, some 16.25″).
• Order rebar separately — the rebar and rebar-spacing calculators handle that.

Frequently Asked Questions