Concrete Calculator
Volume of concrete.
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About Concrete Calculator
The Concrete Calculator estimates how much concrete you need for a slab, footing, or pour. Enter the length, width, and thickness of your project, each in its own unit (feet, inches, meters, or centimeters), and it instantly calculates the total volume in cubic meters, cubic yards, and the approximate number of 25 kg bags required.
It is completely free with no sign-up and no limits. Everything runs entirely in your browser, so your measurements are calculated on your own device and are never uploaded to a server.
Frequently asked questions
- How do I calculate how much concrete I need?
- Measure the length, width, and thickness (depth) of the area you want to fill. Enter each value into the calculator and choose its unit. The tool multiplies the three dimensions to give you the total volume in cubic meters, then converts it to cubic yards and an estimated number of 25 kg bags.
- How many 25 kg bags of concrete are in a cubic meter?
- As a rough estimate, one cubic meter of concrete takes about 85 x 25 kg bags of pre-mixed concrete. The exact number varies by product and mix, so the calculator rounds up and we recommend buying 5-10% extra to cover spillage, waste, and uneven ground.
- Can I mix units like feet and inches?
- Yes. Each dimension has its own unit selector, so you can enter length and width in feet while entering thickness in inches. The calculator converts everything to meters internally before computing the volume, so mixed units are handled automatically.
- How do I convert cubic meters to cubic yards?
- Multiply the volume in cubic meters by about 1.30795 to get cubic yards. The calculator does this for you and displays both figures side by side so you can order concrete in whichever unit your supplier uses.
- Is the Concrete Calculator free to use?
- Yes, it is 100% free with no account, subscription, or usage limits. You can calculate as many pours as you need.
- Is my data uploaded or stored anywhere?
- No. The calculator runs entirely in your browser using JavaScript. Your measurements never leave your device, nothing is sent to a server, and nothing is stored after you close the page.