Concrete Block Calculator
Estimate blocks for a single-layer rectangular wall. Deduct openings, choose nominal dimensions or actual dimensions plus a joint, and compare loose-block and full-pallet quantities.
Changing a unit selector reinterprets the numbers; it does not convert your entries. Update the inputs before calculating. Prices are examples in your own currency.
How to calculate concrete blocks
Subtract door and window openings from wall length × height. Divide that net area by one block’s nominal face area, add your chosen allowance, then round up once. Width through the wall does not change the face-area calculation. This tool covers one wall layer; estimate additional layers separately.
8 × 8 × 16 blocks: which dimensions do I enter?
For a nominal 8-inch-high, 16-inch-long block, enter 16 and 8 in Nominal mode. The mortar joint is already part of that module. Actual mode adds the entered joint to both face dimensions. Do not add a joint twice. Different national block sizes can be entered in metric mode.
Worked example
A 20 × 8 ft wall minus 16 ft² of openings has 144 ft² of net face area. An 8 × 16 inch nominal face gives 162 area-equivalent blocks. With 5% extra, round 170.1 up to 171 blocks. At 90 blocks per pallet, two full pallets contain 180 blocks.
Does this include corner blocks or mortar?
No. Count corners, lintels, bond beams and other special units from the actual layout, then adjust the standard-block order. Area estimates do not resolve cuts or bond patterns. Mortar and core-fill quantities need separate product and layout information. This is a purchasing estimate, not a wall design or structural check.
Method reference: CMHA estimating concrete masonry materials.
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Reviewed 5 November 2026. Free, no signup. Calculations run in your browser. Confirm measurements and product specifications before ordering. Costs exclude labour, tax and delivery.