Concrete Block & Mortar Calculator

Estimate CMU block count, mortar bags, and rebar for a block wall

Frequently Asked Questions

How many blocks are in a square foot?

A standard 16 by 8 inch CMU face covers about 0.889 square feet, which works out to roughly 1.125 blocks per square foot of wall.

How much mortar will I need?

Plan on about three 80 pound bags of mortar mix per 100 blocks. Joint thickness and your masons technique change the exact amount, so order a little extra.

Is the rebar estimate enough for my wall?

No. Reinforcement depends on wall height, grout, and seismic and wind zones. The estimate is for planning only, so verify reinforcement against local code and a licensed structural professional.

Why add a waste allowance?

Cuts, breakage, corners, and partial blocks all add up. A 5 to 10 percent allowance keeps you from running short mid-course.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.