Brick Calculator
Estimate the bricks and mortar for a wall from its length and height or its total area. Choose a standard brick or enter your own size and mortar joint, set single or double wall thickness, add a waste allowance, and turn on an optional cost estimate. Works in metric or imperial with a full worked example.
Formula
Worked example
A 5 m x 2 m wall is 10 m². In US modular brick (0.1937 x 0.0572 m) with a 10 mm joint, one brick covers (0.1937 + 0.01)(0.0572 + 0.01) = 0.01368 m². So 10 / 0.01368 is about 731 bricks per leaf. A single leaf with 10% waste rounds up to about 806 bricks, plus roughly 18 bags of mortar mix.
How the brick count is worked out
The number of bricks in a wall is the wall area divided by the area a single brick occupies on the face of that wall. The key detail is that each brick claims slightly more than its bare dimensions, because a mortar joint of about 10 mm (3/8 inch) sits between every brick on two sides. This calculator adds your chosen joint thickness to the brick length and height, so the face area reflects the real space a brick takes up. Dividing the wall area by that figure gives bricks per leaf; multiplying by the number of brick thicknesses (wythes) and by one plus the waste fraction gives the quantity to buy.
Wall size, custom bricks and joint thickness
You can enter the wall as a length and height (with an optional deduction for doors and windows) or jump straight to a known area. Pick a standard brick format or choose Custom to type your own face length and height in millimetres or inches, which is useful for facing bricks, pavers or non standard imports. The mortar joint defaults to 10 mm but you can set it anywhere from a tight 5 mm to a thick 20 mm bed; wider joints mean fewer bricks per square metre. Switching between metric and imperial converts every field and every result, including the bricks per square foot figure used across North America.
Mortar and cost estimates
Turn on the mortar estimate to see the joint volume and roughly how many bags of mix to buy. As a rule of thumb an 80 lb (about 25 kg) bag of mortar lays in the region of 40 to 45 modular bricks once mixed, and this tool adds an allowance for filling and waste on top of the bare joint volume. The cost estimate prices the two main materials, bricks by the unit and mortar by the bag, in your chosen currency. Treat the total as a planning figure since local prices, delivery and the exact mix vary. For structural walls, sand, cement and lime are often bought separately rather than as pre mixed bags.
Single versus double brick walls
A single leaf (half brick) wall shows one course of bricks across its thickness. Garden, boundary and structural walls are often built as two leaves, a cavity or solid wall, or even thicker, which multiplies the brick count for the same face area. Use the wall thickness selector to set one, two or three leaves. Mortar and labour scale the same way, so a double leaf wall needs about twice the bricks and mortar of a single leaf wall of identical height and length.
Bricks per unit area by size (incl. 10 mm joint, single leaf)
| Brick size | Bricks per m² | Bricks per sq ft |
|---|---|---|
| US modular (7 5/8 x 2 1/4 in) | 73.1 | 6.8 |
| US queen (7 5/8 x 2 3/4 in) | 61.5 | 5.7 |
| US standard (8 x 2 1/4 in) | 69.9 | 6.5 |
| UK metric (215 x 65 mm) | 59.3 | 5.5 |
Approximate quantities for a single-leaf wall, before adding any waste allowance.
Frequently asked questions
Does this include the mortar joints between bricks?
Yes. The calculator adds your chosen mortar joint (10 mm or 3/8 inch by default) to each brick length and height, so the face area used reflects the real space a brick takes up including the gaps. You can change the joint thickness, and the brick count updates automatically.
How much mortar do I need for a brick wall?
Turn on the mortar estimate to see the joint volume and bags to buy. As a guide, an 80 lb (about 25 kg) bag of mortar mix lays roughly 40 to 45 standard bricks, so a typical wall of around 700 bricks needs in the region of 16 to 18 bags. Thicker joints and larger formats use more.
How much waste should I allow for bricks?
A waste allowance of 5 to 10% suits most straight walls. Increase it toward 15% for walls with many doors and windows, decorative bonds, or curved sections where more bricks are cut, and for reclaimed bricks that break more often during handling.
How many bricks are in a square metre?
For a single-leaf wall with a 10 mm joint, expect roughly 60 UK metric bricks per square metre, while smaller US modular bricks run closer to 73 per m². The exact figure depends on the brick format and joint. Double-leaf or solid walls need that many for each brick thickness.