Sand Calculator - How Much Sand Do You Need? (UK)
Work out how much sand you need for a bed or fill: enter the area and depth and it gives the volume, the weight in tonnes, and the number of bulk bags.
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How to use this calculator
Enter the area you're covering and how deep the sand needs to be in millimetres. Choose soft sand for bedding and mortar work, or sharp sand for screeds and under paving.
How we calculate this
- Volume = area × depth, plus 5% wastage.
- Weight = volume × 1.6 tonnes per m³ (typical for damp building sand).
- Bulk bags hold roughly 0.5 m³ (about 800kg), so bags = volume ÷ 0.5, rounded up.
Worked example
A 10 m² area at 50mm deep is 0.5 m³, plus 5% ≈ 0.53 m³ - about 0.85 tonnes, or 2 bulk bags. A bulk bag usually works out cheaper per tonne than handy 25kg bags.
UK notes & gotchas
- Soft sand for bricklaying and rendering; sharp (grit) sand for screeds, concrete and laying slabs.
- Bulk bag weights vary by supplier and how wet the sand is - treat the tonnage as indicative.
- For anything over a couple of bulk bags, loose tipped is usually cheaper than bagged.
FAQ
How many bulk bags of sand are in a tonne?
A bulk bag is roughly 800kg, so a little over one bulk bag makes a tonne. Weights vary with moisture and supplier.
What's the difference between soft and sharp sand?
Soft (building) sand is fine and used for mortar and render. Sharp sand is coarser and used for screeds, concrete and bedding paving.
How deep should a sand bed be?
Around 40-50mm for bedding paving or slabs is typical. Always compact and screed to level.
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