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Mortar Calculator

Calculate mortar bags and sand for laying block, brick, or stone, adjusted for the joint thickness you are working to.

Formula and figures last reviewed by the Cosyslabs team · how we verify

Inputs

Result

Mortar bags (70 lb)
15
Sand needed
16.9 ft³
Units
500 block
Joint thickness
0.375 in
Sand in cubic yards
0.63 yd³

Estimates only. Verify with a licensed contractor or supplier before purchasing. Rough Estimator! is not responsible for shortages, overages, or material variances. See our methodology for formulas and sources.

Formula

Bags = (units ÷ 100) × base rate × (joint ÷ 0.375)   ·   base rate: 3 per 100 block, 7 per 100 brick, 10 per 100 stone

References

  1. ASTM C270 — Standard Specification for Mortar for Unit Masonry
  2. Portland Cement Association — Masonry mortar guidance

Related tools & materials

Don't forget

  • Masonry sand
  • Mortar mix
  • Jointer tool
  • Mixing tub
  • Mason line

Frequently asked questions

Roughly three 70-lb bags per 100 concrete blocks, seven per 100 bricks, and ten per 100 stone units, all at a 3/8-inch joint. Scale proportionally if your joint is thicker.
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Cosyslabs. (2026). Mortar Calculator. Rough Estimator!. https://roughestimator.com/mortar-calculator

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