Concrete Volume Calculator
Length times width times thickness gives cubic metres. Bag count is estimated at seven 40 kg bags per cubic metre.
Your numbers
Volume
1.5m³
Cement bags
11
Weight
3,600kg
Formula
Volume = Length × Width × Thickness ÷ 100
Concrete runs about 2,400 kg/m³. The real bag count varies with the mix ratio and aggregate.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Length (m)The measurement across, side to side. | 5 | 0 and up |
| Width (m)The measurement front to back. | 3 | 0 and up |
| Thickness (cm)How thick one layer is; times the number of layers gives the whole. | 10 | 0.5 and up |
Step by step
Quick reference table
Results when only Length (m) changes and everything else stays put.
| Length (m) | Volume (m³) | Cement bags | Weight (kg) |
|---|---|---|---|
| 2.5 | 0.75 | 6 | 1,800 |
| 3.75 | 1.125 | 8 | 2,700 |
| 5 | 1.5 | 11 | 3,600 |
| 7.5 | 2.25 | 16 | 5,400 |
| 10 | 3 | 21 | 7,200 |
What each result means
| Result | At default values |
|---|---|
| Volume (m³)The space a solid holds — length cubed. | 1.5 |
| Cement bagsBags of cement needed, based on 40 kg a bag. | 11 |
| Weight (kg)Weight in tonnes; one tonne is 1,000 kg. | 3,600 |
Common mistakes
Concrete runs about 2,400 kg/m³. The real bag count varies with the mix ratio and aggregate.
Glossary
- Length
- The measurement across, side to side.
- Width
- The measurement front to back.
- Thickness
- How thick one layer is; times the number of layers gives the whole.
- Volume
- The space a solid holds — length cubed.
- Cement bags
- Bags of cement needed, based on 40 kg a bag.
- Weight
- Weight in tonnes; one tonne is 1,000 kg.
Frequently asked questions
Q. How is Concrete Volume Calculator calculated?
Volume = Length × Width × Thickness ÷ 100 — Length times width times thickness gives cubic metres. Bag count is estimated at seven 40 kg bags per cubic metre.
Q. Can you walk through an example?
With Length 5m, Width 3m, Thickness 10cm, the answer is Volume 1.5m³.
Q. What do I need to enter?
Enter Length, Width, Thickness. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Length (m) moves the answer to Length (m) 2.5 → Volume (m³) 0.75 and Length (m) 10 → Volume (m³) 3. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
Concrete runs about 2,400 kg/m³. The real bag count varies with the mix ratio and aggregate.
Related calculators
Keep your length units consistent across inputs — mixing centimetres and metres throws results far off.