Concrete Volume Calculator

Standard concrete has a density of approximately 2,400 kg/m³. One cubic metre of concrete weighs about 2.4 tonnes. Pre-mixed 60 kg bags contain dry ingredients — adding water increases weight slightly and yields approximately 0.028 m³ of cured concrete per bag.

Always add 5–10% extra to your calculated volume to account for wastage, spillage, slight variations in forms, and uneven ground. Running short mid-pour is a serious problem as concrete must be placed and finished continuously. Having a small amount left over is preferable to stopping and creating a cold joint.

For footings and foundations: 1:2:4 (cement:sand:aggregate) or C20 mix. For slabs: 1:1.5:3 or C25 mix. For driveways: C30 mix or stronger. For structural work: always consult an engineer. Pre-mixed bags specify the application on the packaging. Adding too much water weakens the concrete significantly.