Home › Concrete Block Calculator
Concrete Block Calculator
Estimate how many 8 × 8 × 16 in concrete blocks and mortar bags you need for a wall, minus openings and plus waste.
Advertisement
How to use it
- Enter the wall length and height in feet.
- Subtract the area of any openings.
- Choose the block face size (nominal 16 × 8 in is the standard CMU).
- Read blocks and approximate mortar bags.
How it works
A nominal 8 × 8 × 16 in block covers 16 × 8 in = 0.889 ft² of wall face including the 3/8 in mortar joint, so you need about 1.125 blocks per square foot. Mortar is estimated at roughly one 80 lb bag of type S mortar mix per 30 blocks; actual use depends on joint thickness and skill.
FAQ
How many blocks are in a square foot?
About 1.125 standard 8 × 16 in blocks per square foot of wall.
Do I need to fill the cores?
Reinforced or retaining walls usually need grout and rebar in some or all cores - follow your plans and local code.
Related calculators
Advertisement
Free calculator by BuildTally