Concrete Calculator
Estimate the volume of concrete needed for your project and how many bags to buy.
Concrete Slab Calculator
Your Result
How Concrete Quantity Is Estimated
Volume is calculated by multiplying length × width × thickness. This calculator assumes a standard concrete density of about 2,400 kg per cubic meter to estimate total weight, then divides by your chosen bag size to estimate how many bags you'll need.
Always add 5-10% extra to your estimate to account for spillage, uneven ground, and formwork loss — this calculator shows the exact theoretical amount only.
Frequently Asked Questions
Should I buy extra concrete beyond this estimate?
Yes, it's standard practice to add 5-10% extra to account for spillage, ground irregularities, and formwork variance.
What if my slab thickness varies?
Use the average thickness across the slab for a reasonable estimate, or calculate multiple sections separately for more precision.
Does this work for footings and columns too?
Yes, as long as you can express the shape in terms of length, width, and thickness (or convert the volume for a different shape), the calculation is the same.