Block Calculator
Count the concrete blocks, mortar cement bags and sand any wall needs, using the standard Saudi 20, 15 and 10 cm block sizes and a real breakage allowance.
Calculator
How the calculation works
Blocks = net wall area x 12.5 blocks per square metre, the face count for a standard 40 x 20 cm block. Deduct door and window openings before you apply it, then add 5-7% for breakage and cutting. Mortar runs at roughly one cement bag per 25-30 blocks plus about 0.04 m3 of sand per square metre of wall.
Frequently asked questions
How many blocks are there in a square metre?
12.5 blocks for the standard 40 x 20 cm face. Deduct door and window openings from the gross wall area before applying the figure, or the order will be well over.
When should I use 15 cm or 10 cm blocks?
20 cm for external and thermally loaded walls, 15 cm for main internal partitions, and 10 cm for light non-loadbearing partitions such as duct and wardrobe walls.
Is plaster included in the result?
No. Render is measured in square metres per face, so a wall plastered on both sides is twice the wall area. Price it as a separate item with its own waste allowance.
How many blocks fit on a delivery pallet?
It varies by supplier and block size, so confirm the pallet count when you order — it is what turns a block quantity into a realistic delivery and offloading plan.
Need a whole bill of quantities priced, not one material?
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This calculator is also available in Arabic: حاسبة البلوك.