Topsoil Calculator
Find how much topsoil (or top soil) to buy for a bed, border or new lawn. See the answer in litres, bulk bags and tonnes.
Measure your project
Your answer
That weighs about 0.99 tonnes. We added 10% extra.
If you buy bags
If you buy bulk bags
Rolawn puts 100–150 mm of topsoil under a lawn and 150–200 mm in a border.
Which costs less?
That is 50 bags to carry. For a small job, bags are easy.
Bulk: £109 per 500 litre bag, with VAT. That is the middle of 3 bulk bag prices per m³ (Wickes, Rolawn, Oct 2026). You pay for whole bags. Small bags: £4.50 for 25 litres at B&Q. Few prices, so treat both as a rough guide.
Quick answers
- A 5 × 1.5 m border, 150 mm deep
- About 1,238 litres with 10% extra. That is 3 bulk bags of 500 litres.
- Litres per m²
- The depth in mm is the litres per m². So 100 mm deep takes 100 litres for each m².
- Weight
- About 800 kg per m³, from Wickes's 500 litre bag of about 400 kg.
- Litres in a tonne
- About 1,250 litres, or 1.25 m³.
- Settling
- Field Compost adds 10–15% because new topsoil sinks. Rolawn treads it in 2 or 3 times.
How to work it out
- Measure the length and width of the bed or lawn in metres. Multiply them for m².
- Choose the depth in mm. Divide it by 1,000 to get metres.
- m² × depth in metres = the volume of topsoil in m³. Times 1,000 gives litres.
- Add 10–15% for settling, says Field Compost. We use 10%.
- Divide the litres by the bag size (25, 500 or 750 litres). Round up.
5 × 1.5 × 0.15 = 1.125 m³
1.125 × 1.1 = 1.238 m³ = 1,238 litres
1,238 ÷ 500 = 2.48 → 3 bulk bags
How much top soil for common sizes
Pick the row nearest your bed or border. For a round bed, tap "Round" in the calculator.
| Size | Litres, 100 mm | Bags | Litres, 150 mm | Bags |
|---|---|---|---|---|
| 2 × 1 m | 200 | 1 | 300 | 1 |
| 3 × 1 m | 300 | 1 | 450 | 1 |
| 4 × 1.5 m | 600 | 2 | 900 | 2 |
| 5 × 2 m | 1,000 | 2 | 1,500 | 3 |
| 6 × 4 m | 2,400 | 5 | 3,600 | 8 |
| 10 × 5 m | 5,000 | 10 | 7,500 | 15 |
Sizes as shown, with nothing extra for settling. A part bag is shown as a whole one.
How deep should topsoil be?
- Lawn: 100–150 mm, says Rolawn. Our topsoil for lawn calculator covers turf, seed and top dressing.
- Bed or border: 150–200 mm.
- Settling: new topsoil settles. Field Compost lays 10–15% more than the depth it wants.
Topsoil coverage: bags, bulk bags and tonnes
Bagged topsoil is sold by the litre, not by weight. Small bags hold 25 litres. Bulk bags hold 500 or 750 litres.
| Depth | 25 L bag | 500 L bag | 750 L bag | 1 tonne |
|---|---|---|---|---|
| 50 mm | 0.5 m² | 10 m² | 15 m² | 25 m² |
| 100 mm | 0.25 m² | 5 m² | 7.5 m² | 12.5 m² |
| 150 mm | 0.17 m² | 3.3 m² | 5 m² | 8.3 m² |
| 200 mm | 0.13 m² | 2.5 m² | 3.8 m² | 6.3 m² |
A tonne is about 1,250 litres, at 800 kg per m³ (Wickes).
Topsoil prices, with VAT
- Bulk bags: Wickes (Hallstone Blended Loam) 500 L £109. Wickes (Rolawn Beds & Borders) 500 L £140. Rolawn (Blended Loam) 750 L £155.99. Rolawn also listed a short-term 6.5% surcharge.
- Per m³: those bags work out at £208–£280 per m³.
- Small bags: 25 L at B&Q £4.50; at Wickes £4 (£2.50 on sale), or £5 for SupaGrow.
- Loose, by the tonne: Tiny Tipper (Sussex and Kent) charges £48 a tonne with VAT, for small loads. TARS (Essex and Suffolk) charges about £21 with VAT, for 16 tonnes or more.
We found only 2 or 3 sellers for each, so treat these as a rough guide. Ask a local supplier about delivery.
What is a good topsoil mix? BS 3882
BS 3882 is the British Standard for topsoil that is sold. The 2015 version has two grades:
- Multipurpose: for most jobs, such as grass, trees, shrubs and flower beds.
- Specific Purpose: for special jobs. It comes in types such as acidic or low fertility.
The old 1994 grades were Premium, General Purpose, Economy. Cawood, a soil testing lab, says the newer grades replaced them. So a "general purpose" label uses old wording.
For a bed, border or lawn, buy multipurpose topsoil tested to BS 3882:2015. Rolawn and Day Aggregates both sell topsoil tested to it.
Some topsoil comes ready mixed. Field Compost mixes 70% sandy loam with 30% soil improver, for beds and new lawns.
Questions people ask
How much topsoil do I need?
Multiply length × width × depth, all in metres, for m³. Add 10% for settling. A 5 × 1.5 m border at 150 mm needs about 1.24 m³.
How much topsoil per m² (square metre)?
100 litres per m² at 100 mm deep, and 150 litres at 150 mm. That weighs about 80 and 120 kg.
How many litres in a bulk bag of topsoil?
Wickes sells topsoil in 500 litre bulk bags, and Rolawn in 500 and 750 litre bags. A 500 litre bag of Wickes topsoil weighs about 400 kg.
How many litres of topsoil are in a tonne?
About 1,250 litres. Wickes's 500 litre bag weighs about 400 kg, so a tonne fills about 2.5 bags.
How much area does a bag of topsoil cover?
B&Q prints 0.5 m² for its 25 litre bag. That is 50 mm deep. At 100 mm it covers 0.25 m². A 500 litre bulk bag covers 5 m² at 100 mm.
How do I measure for topsoil?
Measure the length and width in metres. When measuring an odd shape, split it into rectangles and circles, then add them up. Then pick the depth: 100–150 mm for a lawn, 150–200 mm for a border (Rolawn).
How much is a bulk bag of topsoil?
£109 to £155.99 with VAT, for 500 or 750 litres. Per m³ the middle is £218, from only 3 prices.
How do I work out cubic yards of topsoil?
Work out the m³, then divide by 0.7646. A 5 × 1.5 m border, 150 mm deep, is 1.13 m³, or about 1.47 cubic yards. The UK sellers we checked sell topsoil by the litre or the tonne.
Where our numbers come from
- Topsoil weight: Wickes 500 litre topsoil bag (about 400 kg)
- Rolawn: topsoil depth for lawns and borders
- Topsoil settling and 70:30 mix: Field Compost
- Rolawn: preparing to lay turf
- Topsoil bag prices: Wickes 25 L and 500 L bags
- Topsoil 25 L bag covers 0.5 m²: B&Q Verve
- Topsoil tested to BS 3882:2015: Rolawn Blended Loam
- Small-access loose loads per tonne: Tiny Tipper (inc VAT)
- Full-load prices per tonne: TARS Essex & Suffolk (+ VAT)
- Topsoil grades under BS 3882:2015: Cawood lab summary
- Multipurpose topsoil to BS 3882:2015: Day Aggregates
- Unit sizes: NIST Handbook 44, Appendix C (1 ft = 0.3048 m; 1 US gallon = 231 cubic inches)
Made by BuildersCount. Last checked 4 Oct 2026.
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