Mortar bags Calculator: measuring notes and method
Start with a known mortar volume
Obtain the mortar volume from a product estimator or measured joint geometry appropriate to the unit, bed profile and joint layout. A brick count alone is not a mortar volume.
Check bag yield and scope
Use the mixed mortar yield for the exact bag, not the yield of a concrete product with the same weight. If the upstream mortar estimate already includes losses, set the additional allowance here to zero.
Formula
Bags = round up [volume × (1 + waste ÷ 100) ÷ mixed yield per bag].
Product reference: QUIKRETE product yields
Worked examples in metric and imperial units
Illustrative values match Reset example and stay fixed when you edit the calculator. Both columns describe the same calculation; converted inputs are rounded.
Metric worked example
- Required wet mortar volume
- 0.2 m³
- Mixed mortar yield per bag
- 13 L
- Waste allowance
- 10 %
Bags to buy: 17
Imperial worked example
- Required wet mortar volume
- 0.2616 yd³
- Mixed mortar yield per bag
- 0.4591 ft³
- Waste allowance
- 10 %
Bags to buy: 17
Follow the calculation
- Allowance multiplier = 1 + 10 ÷ 100 = 1.1.
- Required volume = 0.2 × 1.1 = 0.22 m³.
- Bag yield = 13 L = 0.013 m³. Divide required volume by 0.013 and round up to whole bags.
Unit conversions
1 m³ = 1,000 L ≈ 1.30795 yd³. One cubic yard is 27 ft³.
Reviewed 19 October 2026. How calculations are checked · Report a correction