Concrete Mix Calculator
Cement bags, sand and gravel for a given volume and mix ratio.
Results
Cement bags
14.8
Mass
370
kg
Volume
0.513
m³
Volume
0.770
m³
What this tool does
Dry materials take up more space than the finished wet mix, so the quantities include the customary 1.54 bulking factor and a cement bulk density of 1440 kg/m³. Treat the result as a shopping estimate rather than a specified mix design.
Formula
share = V ÷ (c + a + b) ; cement = share × c
Variables
| Symbol | Meaning | Unit |
|---|---|---|
v | Volume | m³ |
c | Cement parts | — |
s | Sand parts | — |
gr | Gravel parts | — |
bw | Cement bag weight | kg |
CB | Cement bags | — |
CM | Mass | kg |
SV | Volume | m³ |
GV | Volume | m³ |
Worked example
- Volume1 m³
- Cement parts1
- Sand parts2
- Gravel parts3
- Cement bag weight25 kg
- Cement bags14.8
- Mass370 kg
- Volume0.513 m³
- Volume0.770 m³
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- Density changes with temperature, moisture and composition. Use a value from the supplier's data sheet whenever precision matters.
- Always order a little more material than the calculated quantity. Cuts, breakage and pattern matching create waste that depends on the shape of the job.