Cement Calculator

Cement Calculator. The Cement Calculator takes the guesswork out of ordering materials for concrete projects by converting your dimensions and mix ratio into an exact bag count. Select your project type (slab, footing, wall, or custom volume), enter your length, width, and thickness, then choose your concrete mix ratio, cement bag size, and waste factor. You'll get the total cement bags needed along with total cement weight, concrete volume, and the sand and gravel quantities required for your mix. Also try the find Hole Volume with Hole Volume Calculator.

Results

Cement Bags Needed

Total Cement Weight

Concrete Volume

Sand Needed

Gravel Needed

What is cement and how is it different from concrete?

Cement is a binding agent that hardens when mixed with water. Concrete is a mixture of cement, sand, gravel, and water. Cement makes up about 10-15% of concrete by volume. See also our use the Concrete Tube/Sonotube Calculator.

How much cement do I need for a standard concrete slab?

For a typical 4-inch thick slab using a 1:2:4 mix ratio, you'll need approximately 1 cubic foot of cement for every 15 cubic feet of concrete. Use our calculator above for precise measurements.

What do the different mix ratios mean?

Mix ratios show the proportion of cement:sand:gravel. For example, 1:2:4 means 1 part cement, 2 parts sand, and 4 parts gravel. Higher cement ratios create stronger concrete.

How long does cement take to cure and dry?

Cement typically sets in 24-48 hours but takes 28 days to reach full strength. Factors like temperature, humidity, and mix design affect curing time.

Should I add extra cement for waste?

Yes, it's recommended to add 5-10% extra material to account for spillage, waste, and minor measurement variations. Our calculator includes a waste factor option.

Can I use different bag sizes for the same project?

Yes, but it's easier to calculate and purchase using one bag size. Larger bags (60-80 lbs) are more economical for big projects, while smaller bags (40-50 lbs) are easier to handle.

What is Portland cement?

Portland cement is the most common type of cement used in concrete. It's made from limestone and clay, heated to high temperatures, and ground into a fine powder. You might also find our Concrete Slab Calculator useful.