Enter your area length, width and depth to get the topsoil volume in cubic yards, cubic metres or litres - plus how many bags to buy. Ideal for new lawns, turfing and garden beds. Works in feet/inches or metres/centimetres.
Typical depths: 50–75 mm (2–3 in) for mulch, 40–50 mm for decorative gravel, 100 mm (4 in)+ for new topsoil, deeper again to fill a raised bed. Each area can take its own depth.
Total bed area
10.0 sq ft
In cubic feet
4.2 cu ft
Topsoil is spread to an even depth, so the amount you need is the area times the depth:
volume = length × width × depth
The calculator reports that volume in cubic yards or cubic metres (and litres or cubic feet), then divides by the size of one bag to give the number of bags. Doing a lawn and a separate border? Add an area for each and the volumes pool into one order. All math runs in exact metric internally, so switching units never changes the answer.
A 10 m × 5 m lawn levelled with a 25 mm topsoil layer:
In US units, a 33 ft × 16 ft lawn at 1 inch deep is about 528 sq ft × (1 ÷ 12) = 44 cu ft ≈ 1.6 cubic yards.
| Job | Depth | Notes |
|---|---|---|
| Levelling before turf | 25–50 mm (1–2 in) | Over an existing base |
| New lawn from seed | 100–150 mm (4–6 in) | Roots need depth |
| Top-dressing a lawn | 10–15 mm (≈0.5 in) | Thin layer, brushed in |
| Garden / planting beds | 150 mm+ (6 in+) | Deeper for vegetables |
Multiply the lawn area by the depth. For levelling before turf, 25–50 mm (1–2 in) is usual: a 10 m × 5 m lawn at 25 mm needs 1.25 m³ (1,250 litres). For a new lawn from seed, go deeper at 100–150 mm. Enter your area and depth above for the exact volume and bag count.
For laying turf over an existing base, a 25–50 mm (1–2 in) levelling layer of quality topsoil is enough. For a brand-new lawn from seed, lay 100–150 mm (4–6 in) so roots have depth to establish. Garden beds for planting want 150 mm (6 in) or more. Set the depth in the calculator to match.
Topsoil weighs roughly 1.0–1.3 tonnes per cubic metre depending on how wet and dense it is. It is sold both in bags (often 25 L, 50 L, or large bulk bags around 0.7 m³) and loose by the cubic yard or tonne. The calculator gives the volume in litres and cubic yards plus a bag count so you can pick the cheapest format.
A cubic metre is 1,000 litres, so it is twenty 50-litre bags or forty 25-litre bags. A large bulk bag is usually around 0.7–0.9 m³, so a little over one bulk bag per cubic metre. For anything over about a cubic metre, loose bulk delivery is normally cheaper than bags.
Bags are convenient for small jobs - top-dressing a lawn or filling a few planters - and easy to store. For a new lawn or a large bed, bulk delivery by the cubic yard or tonne is much cheaper per unit. The calculator returns both a bag count and a bulk volume so you can compare the two.
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