Home Improvement
Cement Calculator
Enter length, width and depth to estimate volume, bags and optional cost.
Cement
Bagged cement and concrete-mix are ordered by how much volume you need to fill, not by a vague “few bags” guess. Measure the length and width of the pour or bed, decide the depth, then convert cubic metres to litres (1 m³ = 1,000 L) and divide by the bag size printed on the pack. A waste percentage covers spillage, uneven bases and the odd short bag. Compaction and whether you are buying neat cement versus all-in mix change how far a bag goes in practice, so treat the count as a shopping list, not a structural mix design. For related bulk fills see the sand calculator and the gravel calculator.
Worked example
A 5 × 3 m area at 10 cm depth is 1.5 m³. With 10% waste that is 1.65 m³ (1,650 L). At 25 L per bag you need 66 bags; at £4.50 each that is about £297.
Limits and assumptions
Volume and bag maths only. Mix ratios, reinforcement, cure time and structural suitability are out of scope — follow product data sheets or an engineer for load-bearing work.
Frequently asked questions
Is this neat cement or concrete mix?
Enter the bag size of whatever you are buying. Neat cement and ballast mixes share the same volume maths but different jobs and coverage.
Should I buy bulk instead of bags?
Above roughly a cubic metre, loose or bulk-bag deliveries are often cheaper. Convert the litre total to m³ when talking to a merchant.
What waste percentage is typical?
Many DIY pours use 5–10% for spillage and low spots. Complex formwork or first-time mixing may need more.
Does settle after pouring change the count?
Yes — some mixes shrink or settle. If the surface must stay flush, keep a spare bag or raise waste slightly.