Sand And Cement Calculator For Brickwork

1:4 (cement:sand) is the most widely used general-purpose mix for standard UK domestic brickwork above the damp-proof course, striking a balance between strength and flexibility. Use a stronger 1:3 mix for exposed brickwork, retaining work, or anything below the damp-proof course; step down to a weaker 1:5 or 1:6 mix for soft, handmade or reclaimed bricks, since mortar that's stronger than the bricks it joins can crack the bricks themselves rather than the joint when the wall moves.

A standard UK brick (215 x 102.5 x 65mm) laid with a 10mm mortar joint gives 60 bricks per m² for a half-brick (single-skin, 102.5mm thick) wall, or 120 bricks per m² for a one-brick (double-skin, 215mm solid) wall. Multiply your wall's net area (length x height, minus any door or window openings) by the figure for your wall type, then add a waste margin - this calculator does that for you automatically.

A one-brick (215mm solid, double-skin) wall uses twice as many bricks per m² as a half-brick (102.5mm single-skin) wall - 120 vs 60 - because it's built from two brick thicknesses rather than one. Since mortar quantity scales with the number of bricks laid, a one-brick wall of the same footprint needs roughly double the cement and sand.

Building sand (also called soft sand or bricklaying sand) is finer and gives a smoother, more workable mortar suited to laying bricks and blocks - it's what this calculator assumes. Sharp sand is coarser and used mainly in concrete and some render mixes, not standard bricklaying mortar; using sharp sand for brickwork mortar tends to produce a harsher, less workable mix that's harder to strike neat joints with.

A standard bulk ("jumbo" or "builder's") bag of building sand holds around 0.85 tonnes - this calculator's figure - though some suppliers quote a slightly different weight (commonly 800kg-1000kg), so check the exact figure with whoever you're buying from, since it directly affects how many bags you need to order.

As of 2026, a bulk bag of building sand typically costs roughly £35-£50 delivered, and a 25kg bag of cement typically costs roughly £5-£7.80, according to P P O'Connor Aggregates' 2026 sand price guide and Gilmore Building Supplies' bag-price guide. Enter your own supplier's prices above for an estimate specific to your job - this calculator never assumes a default price.

Traditional lime mortar mixes (roughly 1:1:6 cement:lime:sand, the UK "M4" designation) add workability and let older masonry breathe and move slightly without cracking, and are commonly specified for period or listed buildings. For most modern domestic brickwork, a plain cement:sand mix with a plasticiser (a liquid additive that improves workability without lime) is the more common, simpler choice - check with a heritage or conservation specialist if you're repairing a period property.

10% is a commonly used default that covers typical spillage, mixing losses, and the occasional dropped or cracked brick during laying. Use a higher margin (15%) if you're a first-time DIY bricklayer, working with an irregular or reclaimed brick, or want a comfortable buffer rather than an emergency mid-build trip to the merchant.

10mm is the standard modern UK mortar joint width for machine-made bricks of consistent size. A wider 12mm (or occasionally more) joint is common with handmade, reclaimed, or older bricks that vary more in size, since a wider joint gives more room to take up that variation - check what joint width matches the brick you're using or matches an existing wall you're extending.

Not directly - this calculator's bricks-per-m² and mortar-volume figures are based on a standard 215 x 102.5 x 65mm brick, not the larger dimensions of a typical concrete block (commonly 440 x 215mm). Blockwork uses fewer, larger units per m² and a different mortar volume per unit - use a block-specific calculator or supplier guidance for a block wall.

No - this tool calculates mortar for laying bricks above an existing, adequate foundation. If you also need to pour a new concrete footing or base first, that's a separate concrete calculation (different mix ratio, volume and materials) - see CoryVu's ballast and cement calculator for a concrete base for that step.

This calculator assumes a simple rectangular wall (length x height). For an L-shaped wall, a wall with a stepped top, or one with piers, split it into two or more rectangles, calculate each separately, and add the resulting bag counts together.

Yes, if they're a meaningful share of the wall - a standard UK external door opening is roughly 2.0-2.1 m², and a standard window roughly 1.0-1.5 m². Deducting openings avoids over-ordering bricks and mortar for area you won't actually be laying; leave the field at 0 if your wall has no openings or you want a simple over-estimate as a safety buffer.

No. It estimates materials from widely used UK trade mortar ratios and brick coverage rates for a standard domestic wall. It is not a substitute for a structural engineer's assessment on anything load-bearing, retaining, taller than a typical garden wall, or otherwise unusual, and it does not cover building regulations or planning permission, which depend on your specific project and local authority.

Mortar reaches a workable initial set within a few hours but continues gaining strength for around 28 days, similar to concrete. Avoid applying significant load (rendering, coping stones, further courses beyond a sensible daily lift) to freshly laid brickwork too soon, and avoid laying in frosty conditions, since freezing before the mortar has set can seriously weaken the joint.