Splitting a mix ratio into material quantities
Enter the volume to be placed, the cement, sand and gravel ratio by volume and the loose unit weight of each material. The page returns the volume and weight of every material. A waste allowance is applied to the total first, and the adjusted volume is then split by the ratio. Set the gravel ratio to 0 and the same page works for a mortar mix.
Mix ratios, loose unit weights and waste allowances change with the source of the material and with site conditions, and none of them has been confirmed in an authoritative source. No defaults are offered, so every one of them is entered by you. The calculation uses proportional volume and the definition of mass only. Leave a unit weight blank or at 0 and that material shows its volume only, while the other materials are still calculated in full. Figures are current as of October 2026.
Weight based mix design, water to cement ratio and material prices are not covered. If the figures you enter are a weight ratio rather than a volume ratio, read the results on that basis. This calculator is for reference and does not replace design work; review by a qualified engineer is required.
Frequently Asked Questions
This page treats the ratio you enter as a volume ratio. If you work from a weight ratio, multiplying by a unit weight again would double count, so check your source first.
No authoritative figure is offered. Enter the allowance your site or your client uses. Entering 0 runs the split with no adjustment.
Yes. Enter 0 for the gravel ratio and gravel is reported as not used, with only cement and sand split out.