onlinecalculator.me

Free online brick calculator

A brick calculator counts the courses and bricks per row for a wall, subtracts door and window openings, and estimates mortar bags — all from your wall dimensions and brick size.

About this 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).

Frequently asked

How many bricks do I need per square foot?
Standard modular brick (7.625 × 2.25 in face) with a 3/8-in mortar joint covers about 6.75 bricks per square foot of wall face. The calculator derives this automatically from your brick and joint dimensions.
What is a course of brick?
A course is one horizontal row of bricks. Course height equals brick height plus mortar joint thickness. For standard brick with a 3/8-in joint, each course is 2.625 in tall (about 4.57 courses per foot).
How much mortar do I need?
A 60-lb bag of mortar mix covers approximately 35 bricks with standard 3/8-in joints. The calculator divides bricks needed (with waste) by 35 to find bag count.
How are door and window openings handled?
The calculator subtracts 100 bricks per door opening (assumed 3 ft × 7 ft) and 57 bricks per window opening (assumed 3 ft × 4 ft). For non-standard openings, adjust the door or window count proportionally.
What waste factor should I use for brick?
5% is standard for experienced masons on a straightforward rectangular wall. Use 10% for cut-heavy work (corners, curves, arches) or if you are new to bricklaying.
How do I share my brick estimate?
Click Share to copy the page link, or Share with my numbers to encode your inputs in the URL.