Mortar Calculator: Bags, Volume and Batch Size

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Opens on the book's own wall. Change any number to your own and press Calculate.

Blocks to lay

Blocks per bag Mason Mix 80 lb: up to 13

Waste allowance %

Extra bags e.g. bedding the coping

Price per bag

Wall face m²

Blocks per bag of masonry cement 70 lb bag

Your laying rate blocks per hour

Mortar working life hours

Enter the blocks and press Calculate.

From the book, Chapter 5. The book's 105 blocks take 9 bags of Mason Mix with 10% waste, plus 1 for the coping: 10 bags. By volume (6.0 ft³ per 100 ft² of 8 in block wall, FM 5-428) that is about 5.4 ft³.

Mortar is placed within about 2½ hours of mixing; do not add water to mortar that has started to set. Below about 4 °C (40 °F) masonry needs special measures. Prices are illustrative US home-center prices from October 2026, shown without a currency sign; put in your own. Everything stays in your browser: no sign-up, nothing stored.