Mortar Calculator
Mortar use depends on the unit count, so you need your brick or block total divided by the units one bag lays — about 125 bricks or 30 blocks per bag. Enter your count below.
How to estimate mortar
Mortar is tied to the number of units, not the wall area. Divide your brick or block count by the units one bag lays — about 125 bricks or 30 blocks per 80 lb bag — and round up. Get the unit count from the brick calculator.
Mixing your own
Pre-mixed mortar already contains sand. If you mix masonry cement and sand yourself, plan on roughly one cubic foot of sand per bag of cement. The calculator estimates the bedding sand alongside the bag count.
Joint width matters
Standard 3/8-inch joints match the figures above. Wider or heavily raked joints use noticeably more mortar, so round up and keep a spare bag. For the structural pour behind a wall, see the concrete calculator.
Frequently asked
How many bricks does a bag of mortar lay?
About 125 standard bricks per 80 lb bag of mortar mix, or roughly 30 standard concrete blocks. Wider joints and rough units use more.
How much sand do I need for mortar?
If you mix your own, plan on roughly one cubic foot of sand per bag of masonry cement. Pre-mixed mortar already includes the sand.
How do I know my unit count?
Use the brick calculator to get the brick total for a wall, then bring that number here to size the mortar.