MEASURE, CALCULATE, CHECK
Mortar bags Calculator guide
Use the method below to check your estimate before turning it into an order.
Use mixed yield per bag
Divide required finished volume including allowance by the yield on your product, then round up to whole bags. Dry bag weight is not mixed volume.
Bags = round up [volume × (1 + waste ÷ 100) ÷ mixed yield per bag].
Worked examples in metric and imperial units
These examples describe the same project using the calculator’s starting values. Converted inputs are rounded here for readability; calculations use full precision. These reference examples stay fixed when you edit the calculator above.
Metric worked example
- Required wet mortar volume
- 0.2 m³
- Mixed mortar yield per bag
- 13 L
- Waste allowance
- 10 %
Bags to buy: 17
The purchase count is rounded up to a whole unit.
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
The purchase count is rounded up to a whole unit.
Units and products around the world
Choose the system matching your measurements. Product sizes, pack yields and installation specifications vary by supplier and country; replace example inputs with your actual project values.
1 m³ = 1,000 L ≈ 1.30795 yd³. One cubic yard is 27 ft³. Convert dimensions before multiplying; millimetres and inches cannot be multiplied directly with metres and feet.
Frequently asked questions
Can I infer yield from bag weight?
No. Equal-weight products can have different yields. Use the product data sheet and prescribed mixing instructions.
What should I check before using this estimate?
This tool requires your mortar volume estimate. Product yield varies with mix and water content.
Should I use the example allowance?
Choose an allowance for your measured project, layout and product. The starting percentage is an editable example. Do not apply it again if the input already includes the same allowance.