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Brick calculator: how many bricks or blocks do I need?

Units

1. Walls to build

Enter the length and height of each wall: their areas are added together.

    Openings to subtract

    Doors, windows, patio doors: their area is taken off the wall area.

      2. Brick or block and joint

      Length and height are the face you see once laid (a UK brick laid flat shows 215 × 65 mm and builds a 102.5 mm wall). Enter actual sizes, without the joint: a US block sold as 16 × 8 × 8 in actually measures 15 5/8 × 7 5/8 × 7 5/8 in, and the 3/8 in joint brings it back to 16 × 8. A joint of 0 suits glued blocks. Waste covers breakage and cuts: 5% is common practice. The count per pallet is on the supplier's sheet.

      3. Mortar

      Estimated from the volume of the joints: area × wall thickness × share of the wall face taken by joints, assuming full joints across the whole thickness. Waste is added (20% by default: dropped mortar, uneven joints). The dry volume of cement and sand is about 1.27 times the volume of wet mortar; it is split by the mix, then turned into weight with 1,300 kg/m³ (81.2 lb/ft³) for cement and 1,600 kg/m³ (99.9 lb/ft³) for sand. 1:3 is a richer mix than 1:4; 1:4 to 1:6 is common for brickwork. Water is a starting point (0.55 lb of water per lb of cement): add it gradually until the mortar is workable. US blocks are often laid with mortar on the face shells only, which uses less. Thin-joint blocks and gypsum blocks use adhesive: follow the maker's instructions.

      4. Budget (optional)

      5. Result

      To buy, waste included —

      Step-by-step working

        Bond beams, lintels, columns and special corner units are not calculated: the concrete and steel they need are counted separately (see the concrete calculator). Corner and half units replace standard ones without changing the total much.

        Your measurements and settings stay on this device and come back on your next visit. The copied link reopens the calculation with the same values.

        How many bricks do I need for my wall?

        This brick calculator takes the area of your walls, subtracts doors and windows, then divides by the space one brick or block takes with its mortar joint. It gives the number of units per square foot or square metre, the total to buy with waste, the number of pallets and an estimate of the mortar: volume, bags of cement, sand and water for the mix you choose. It works as a block calculator too, for US concrete blocks (CMU) and other sizes, in feet and inches or in metric.

        How to use it

        1. Pick Imperial (ft, in) or Metric (m, cm, mm), then enter the length and height of Wall 1. Use Add a wall for more.
        2. Under Openings to subtract, enter the width and height of each door or window.
        3. Choose a size in Brick or block, or type your own (Custom size), then set the Mortar joint and the Waste.
        4. Optional: enter the Pieces per pallet from your supplier.
        5. Set the Cement : sand mix and bag sizes, then read the Result box and the step-by-step working.

        Worked example: a 20 × 8 ft wall in modular brick

        US modular bricks (7 5/8 × 2 1/4 in face, 3 5/8 in deep), 3/8 in joints, 5% waste, one 3 × 7 ft door, a 1:4 mix, 94 lb bags of cement and 50 lb bags of sand.

        • Wall: 20 × 8 = 160 sq ft. Door: 3 × 7 = 21 sq ft. Area to build: 139 sq ft.
        • One brick plus its joint takes 8 × 2.625 in, or 0.1458 sq ft: 6.86 bricks per sq ft.
        • Without waste: 139 × 6.8571 = 953.14. With 5% waste: 1,000.80, so 1,001 bricks.
        • Joints take 18.3% of the wall face. Mortar: 139 × 0.3021 ft × 18.3% = 7.69 cu ft, or 9.22 cu ft with 20% waste.
        • Dry volume: 9.22 × 1.27 = 11.71 cu ft, in 5 parts. Cement: 190 lb, so 3 bags of 94 lb. Sand: 9.37 cu ft, or 936 lb (19 bags of 50 lb). Water: about 12.5 gallons.

        The same tool covers the other common cases:

        • US concrete block 16 × 8 × 8 in: actual size 15 5/8 × 7 5/8 in, so with the 3/8 in joint exactly 1.125 blocks per sq ft. A 40 × 6 ft wall (240 sq ft) needs 270 blocks, 284 with 5% waste.
        • UK standard brick 215 × 102.5 × 65 mm with a 10 mm joint: 225 × 75 mm per brick, 59.26 bricks per m², the familiar "60 per square metre". A garden wall 10 m long and 0.9 m high (9 m²) takes 533.33 bricks, 560 with 5% waste.
        • Hollow block 50 × 20 × 20 cm with a 1 cm joint: a wall 8 × 2.5 m with a 0.9 × 2.1 m door leaves 18.11 m², at 9.34 blocks per m², so 178 blocks with 5% waste.

        How the mortar is estimated

        The calculator works out the real volume of the joints: wall area × wall thickness × the share of the face taken by joints, assuming full joints, then adds waste. Dry cement and sand take up about 1.27 times the volume of wet mortar. That dry volume is split by the mix (1 + 4 = 5 parts for 1:4) and converted into weight. Lintels, bond beams and columns are not calculated: count their concrete separately with the concrete calculator.

        Tips before you order

        • Check the actual size on the product sheet: a thicker joint lowers the count per square foot.
        • Bricks and blocks often come by the pallet or cube: compare the unit price with the pallet price.

        Frequently asked questions

        How many bricks per square foot?

        For US modular brick with 3/8 in joints, 6.86, often rounded to 7. For UK bricks with 10 mm joints, 59.26 per m².

        How many concrete blocks per square foot?

        For a 16 × 8 in block, 1.125 per sq ft, or 112.5 blocks per 100 sq ft before waste.

        Should I subtract doors and windows?

        Yes. Add each one under Openings to subtract and its area is removed first.

        What mortar mix should I use?

        For general brickwork, 1:4 to 1:6 cement to sand is common; 1:3 is richer and stronger. Follow the cement maker's guidance.