Count ICF blocks and concrete for insulated concrete form walls.
Enter the total wall length, wall height, and concrete core size to get the number of standard 48 × 16-inch ICF blocks plus the concrete needed to fill them. Subtract window and door openings for a tighter count, and set your local block price to estimate the cost of the forms.
How it works
Block count is net wall area (length × height, minus openings) divided by 5.33 sq ft — the face of a standard 48 × 16-inch form — plus your waste allowance for cuts. Concrete is net area × core thickness: a 6-inch core takes 0.5 cu ft per square foot of wall, which works out to about 0.1 cubic yards per block. Brands vary in form size and web design, so confirm the final order against your supplier's spec.
Frequently asked questions
How many ICF blocks do I need?
Divide net wall area by 5.33. A standard ICF form is 48 inches long by 16 inches tall — 5.33 sq ft of wall per block. Subtract window and door openings, then add about 5% for cuts. A 120-ft wall at 9 ft tall with 80 sq ft of openings needs roughly 197 blocks.
How much concrete does an ICF wall use?
Net wall area × core thickness. A 6-inch core uses 0.5 cu ft of concrete per square foot of wall — about 0.1 cubic yards per standard block, or roughly 18.5 cubic yards for 1,000 sq ft of wall. Order around 5% extra so the pour doesn't come up short.
How much do ICF blocks cost?
Typically $20–$30 per standard block, which is about $5–$7 per square foot of wall for the forms alone. Concrete, rebar, bracing, and labor are separate, and installed wall costs vary widely by region — use the editable price field with a local quote for a real number.
What about corner blocks?
Corners use dedicated 90° (or 45°) corner forms sold separately — typically one per corner per 16-inch course, so a 9-ft wall needs about 7 corner forms at each corner. This calculator counts everything as standard blocks for estimating; split the order per your brand's spec.
Is this calculator free and private?
Yes. Every CubicCabin calculator runs entirely in your browser, so the numbers you enter are never uploaded or stored. There's no sign-up, no limits, and it keeps working even if you lose connection after the page loads.