Concrete & Masonry Calculators
Concrete block, cinder block, and retaining-wall block — counts plus the mortar to lay them.
- Concrete Block CalculatorA standard concrete block (CMU) is 8 × 8 × 16 inches, and it takes about 1⅛ blocks to cover a square foot of wall. Enter the wall size for the block count and mortar.
- Cinder Block CalculatorA cinder block is a lightweight masonry unit in the standard 8 × 8 × 16-inch size, so it covers a wall at the same rate as a concrete block — about 1⅛ blocks per square foot. Enter the wall size for the block and mortar counts.
- Retaining Wall CalculatorEnter the wall's length and height and your block's face size, and this gives the number of retaining-wall blocks and courses — the materials count, not the engineering.
- Rebar CalculatorFor a reinforced slab on a grid, this estimates the rebar — total linear feet, 20-foot sticks, and bar count — from the slab size and the spacing you choose.
- Mortar CalculatorEnter the wall area and whether you're laying block or brick, and this estimates the bags of mortar — with the bags-per-100 figure left editable, since it varies by mortar type and joint.
- Sonotube CalculatorA round form (Sonotube and similar) holds a cylinder of concrete. Enter the diameter, pour height, and number of tubes for the concrete volume and the bags of mix to buy.
- Concrete Slab CalculatorEnter your slab's length, width, and thickness for the concrete it needs — by the cubic yard (how ready-mix is ordered) and by the bag (for small pours).