Work out exactly how much topsoil you need for beds, borders and lawn prep. Enter your length and width (or the total area), pick a depth, and we calculate the volume in litres and cubic metres — then price up the cheapest way to buy it in bulk bags or handy bags.
As a rule of thumb you need 10 litres per square metre for every centimetre of depth. A standard bulk bag holds around 730 litres, so one bag covers roughly 7m² at 10cm deep.
01 — The Calculator
Pick a material, pace out your plot, and the value engine prices every way to fill it — hippo bags, dumpy bags or handy sacks.
Enter dimensions to calculate.
Volume
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Cubic
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Area
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Enter your plot size below — we'll price the cheapest way to cover it.
10 cm
Depth changes the volume a lot — 5cm mulch is normal, raised veg beds want 20cm+.
Not sure? See the depth guide belowWhy allow extra? See why soil settles after laying
Worked example: raised veg beds
Two raised beds totalling 10m², filled to 20cm deep: 10m² × 20cm × 10 litres = 2,000 litres (2m³). That's 3 standard bulk bags of 730L, or 27 handy 75L bags — the calculator compares both and flags the cheaper option.
For lawns, spread 10–15cm of screened topsoil over firmed subsoil — turf roots establish in the top 10cm, so going thinner starves the lawn from day one. Beds and borders want 20–30cm, and raised vegetable beds at least 25–30cm if they're sitting on concrete or poor ground. Always choose BS3882-certified screened soil for anything you're planting into; unscreened as-dug soil is cheaper but full of stones and only suits filling big holes where the finish doesn't matter.
Allow an extra 10% for settling — soil compacts after the first few rains, and a bed that looks perfectly level on day one will sit below its edging by spring. Topsoil weighs roughly 1.3 tonnes per cubic metre, so a full bulk bag is close to a tonne: check the lorry can get within barrow distance, or pay for crane offload. Bulk bags work out far cheaper per litre than handy bags once you need more than about 300 litres, so use the calculator's comparison before ordering.
Allow 10 litres per m² for every 1cm of depth. So 10m² at 10cm deep needs 10 × 10 × 10 = 1,000 litres (1m³).
Last reviewed: October 2026 · Reviewed by the Garden Calculator editorial team.
Garden Calculator — Project
My garden project · 28 October 2026
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Prices from the Garden Calculator sample trade catalogue — confirm with your merchant before ordering.