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Kg to Bags Converter — How Many Bags Do I Need?
Convert a total weight in kilograms to the number of bags you need to buy. Covers cement, plaster, sand, aggregate, postcrete, and more with standard UK bag sizes.
How many kg of material do you need in total?
Enter your supplier price for a cost estimate
How We Calculate This
This converter divides your total weight requirement by the selected bag size, then rounds up to the nearest whole bag. You cannot buy partial bags, so we always round up to ensure you have enough material.
The formula
Bags needed = ROUNDUP(Total weight ÷ Bag size)
For example, if you need 120kg of cement in 25kg bags: 120 ÷ 25 = 4.8, rounded up = 5 bags. You'll have 5kg spare (5 × 25 = 125kg total purchased).
Standard UK bag sizes
- Cement: 25kg bags
- Plaster: 25kg bags
- Sand / Aggregate: 25kg bags or 850kg bulk bags
- Postcrete: 20kg bags
- Self-Levelling Compound: 20kg bags (most brands; some come in 25kg)
- Tile Adhesive: 20kg bags
- Grout: 5kg bags
Frequently Asked Questions
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Last updated: February 2026
Verified against UK standards · estimates only, confirm with your supplier.