Free online brick calculator

How to use

1. Enter the wall length and height in feet.
2. Enter the number of doors and windows to subtract from the total.
3. Use the default standard modular brick dimensions or enter your own.
4. Set the mortar joint width (3/8 in is standard).
5. Set a waste factor (5% is typical for a straight wall).
6. Read brick count, courses, and mortar bags.

Formulas

bricksPerRow   = ceil(wallLength × 12 / (brickLength + mortarJoint))
courses        = ceil(wallHeight × 12 / (brickHeight + mortarJoint))
rawBricks      = bricksPerRow × courses

bricksNeeded   = rawBricks − (doors × 100) − (windows × 57)
bricksWithWaste = ceil(bricksNeeded × (1 + waste% / 100))

mortarBags     = ceil(bricksWithWaste / 35)   [60-lb bags]

Worked example

20 ft × 8 ft wall, 1 door, 2 windows, standard brick (7.625 × 2.25 in), 3/8-in joint, 5% waste:

bricksPerRow   = ceil(20 × 12 / (7.625 + 0.375))
               = ceil(240 / 8) = 30

courses        = ceil(8 × 12 / (2.25 + 0.375))
               = ceil(96 / 2.625) = ceil(36.57) = 37

rawBricks      = 30 × 37 = 1,110

bricksNeeded   = 1,110 − (1 × 100) − (2 × 57)
               = 1,110 − 100 − 114 = 896

bricksWithWaste = ceil(896 × 1.05) = ceil(940.8) = 941

mortarBags     = ceil(941 / 35) = ceil(26.89) = 27 bags

Notes

• The door and window deductions use standard rough opening sizes (3×7 ft doors, 3×4 ft windows). Adjust the count if your openings are significantly larger or smaller.
• Mortar coverage varies with joint thickness, mason technique, and brick porosity. Add 10% to the mortar bag count for any first-time project.
• For double-wythe walls, multiply brick count and mortar bags by 2 (plus ties).