Mortar Calculator

Mortar is the glue of a masonry wall, and its quantity follows the number of joints rather than the wall area directly. Every brick or block laid needs a bed underneath and a joint at one end, so the mortar consumed is roughly proportional to the number of units — which is why small units and wide joints use much more mortar than large blocks with tight joints. The working figure for a standard brick is about two hundredths of a cubic foot of mortar per unit, and for larger blocks rather more because the bed and joint are wider. Multiplying units by that figure gives the wet volume, but the dry mix you buy is bulkier than the wet mortar it makes, so bags are estimated by yield rather than by matching volumes. A typical eighty-pound bag of mortar mix yields around two-thirds of a cubic foot of mortar. Waste is larger here than in most building estimates. Mortar is mixed in batches, and any batch left unused at the end of a session sets hard and is thrown away. It is also lost to the board, the trowel and the joints that are struck and brushed. An allowance of ten per cent is a sensible minimum; on small jobs where you cannot mix an exact batch, it can be higher still. This calculator turns your wall area into a unit count, then into mortar volume and bags of dry mix. It assumes brick-sized units unless you change the units-per-square-foot figure, and a single skin of wall. The mix ratio also matters for strength and weather resistance, so follow the specification for your project rather than improvising, and check the yield printed on the bag you buy.

This calculator returns estimates for planning and general information only. It is not engineering, architectural, structural, electrical or code advice, and it cannot replace a qualified professional who has seen the site. Material quantities depend on the actual dimensions, the product you buy and local building codes, so confirm the figures before ordering materials or starting work, and always follow local regulations.