By Zencalcy Editorial TeamLast reviewed About us
Mortar is the thin bed between masonry units, so its volume scales with wall area and joint thickness rather than the number of bags a wall 'looks like' it needs. As a working rule, a 1:3 mortar mix covers about 25–30 square feet of 8-inch block wall per 80 lb bag.
Mortar bags for a brick or block wall.
Bags = area ÷ coverage per bag × joint factor
Coverage is about 30 sq ft per 80 lb bag for 8-inch block, 25 sq ft for brick and 20 sq ft for a 12-inch block. A 3/8 inch joint is assumed; thicker joints scale the bag count proportionally.
| Symbol | Meaning |
|---|---|
| A | Wall area. |
| c | Coverage per bag. |
| N | Bags needed. |
At 30 sq ft per bag, 200 sq ft needs 6.7 bags — buy 7, or 8 with a waste allowance.
Continue with the Cement Calculator, Concrete Calculator, Concrete Block Fill Calculator, or the Concrete Column Calculator — or browse more cement & concrete and all construction calculators.
About three 80 lb bags of mortar mix for 100 standard 8-inch blocks, or five bags for 100 bricks.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
Estimate decking boards by length, screws, hidden fasteners and waste
Calculate concrete blocks needed for wall construction
Calculate full deck materials list including boards, joists, beams, posts, and cost estimates
Price hardwood the way the lumber yard does — by board footage.
Turn measured dimensions into the cubic yards concrete and gravel are sold in.
How many gallons it takes to cover an area at a given depth.
Content updated: September 2026