Concrete Calculator

Concrete volume for slabs, footings and columns, plus bags.

Dimensions

LengthmWidthm

Thickness / depthmm

QuantityWaste allowance%

Concrete required

Total volume (incl. waste)

1.32 m³

1.726 yd³ · 46.62 ft³

Volume before waste

1.2 m³

Approx. weight

3.17 tonnes

Pre-mix bags needed

Bags needed
Bag size	Bags
20 kg bag	139
25 kg bag	111
40 lb bag	156
60 lb bag	104
80 lb bag	78

For larger pours (over ~1 m³ / 1.3 yd³), ready-mix truck delivery is usually cheaper and gives a more consistent finish.

About the Concrete Calculator

Estimate the concrete needed for a slab, footing or round column. Enter dimensions in metric or imperial units, add a waste allowance and see the volume plus how many premix bags you would need.

How to use it

Choose the shape and units.
Enter the dimensions and quantity.
Add a waste allowance (5–10% is typical).

Formula & method

Slab = length × width × thickness
Column = π × (diameter ÷ 2)² × height

Frequently asked questions

How much extra concrete should I order?

Add 5–10% for spillage, uneven ground and over-excavation. Running short mid-pour is far more costly than a small surplus.

Results are estimates for general information only and are not financial, tax, legal or medical advice. Please confirm important decisions with a qualified professional.