How Many Litres in a Tonne?

The Short Answer

By Gary Hodson · Ex-Army. I do the sums so you buy the right amount. · Water, topsoil, gravel, sand, bark, sub-base, unit and bulk-bag figures checked against the numbered sources below; the 830 L topsoil, 1,500 kg gravel and 2,100 kg sub-base figures are GardenCalc calculator working figures · Last reviewed 1 October 2026

For water, a tonne is almost exactly 1,000 litres, since a litre of it weighs about a kilo. For garden materials it is nowhere near. A tonne of topsoil is roughly 670 to 830 litres (heavier products about 590), a tonne of gravel about 556 to 714, a tonne of dry coarse sand about 625, and a tonne of bark over 4,000, because bark weighs almost nothing per litre compared with stone. The table below has the figures with the source next to each one.

Each outside figure was re-checked against the numbered source on 1 October 2026; the numbers in square brackets link to the Sources list at the end. Where two sources disagree, both are shown rather than averaged, because the spread is the useful bit.

Why the Answer Changes With the Material

A litre is a volume. A tonne is a weight. The only thing that turns one into the other is density, which is how much a given volume of the stuff weighs. Water is the easy one: a litre of it weighs about a kilo, so a tonne is about 1,000 litres. It moves a little with temperature, not enough to matter to a wheelbarrow.^[1]

Nothing you buy for the garden behaves like water. Gravel is heavier than water for its size, so a tonne of it takes up less room, around 600 litres. Bark is much lighter than water for its size, so a tonne of bark takes up a huge amount of room, thousands of litres. Topsoil sits in between and moves about depending on how wet it is on the day it was bagged.

That is why a supplier quoting you "a tonne" and a supplier quoting you "a bulk bag" are not necessarily selling you the same amount of anything.

Topsoil: Litres Per Tonne

Roughly 670 to 830 litres. Rolawn, a UK topsoil producer, works on 0.67 cubic metres per tonne, which is 670 litres, for its standard topsoil.^[2] Our own topsoil calculator uses 830 litres per tonne. Those two figures set the 670 to 830 range; heavier products give fewer litres, down to about 590.

Other suppliers land either side of that. South Wales Turf & Top Soil says a tonne of screened topsoil is around 750 litres, or 1.3 tonnes to the cubic metre.^[3] British Sugar TOPSOIL lists its BS 3882 topsoils at 1.6 and 1.7 tonnes per cubic metre at light consolidation, which works out at about 590 to 625 litres a tonne.^[4] So if your supplier gives a density for its own product, use theirs.

The spread is real, not sloppiness. Wet soil weighs more per litre than dry soil, and a screened blended loam behaves differently to a heavy site-won topsoil. If you are ordering to fill a known space, work in litres or cubic metres and let the supplier convert, rather than ordering a weight and hoping.

One thing worth knowing if you are checking figures elsewhere: BS 3882:2015, the British Standard people cite for topsoil, is about quality and composition. The supplier summary of the standard we read gives grades and test properties but no bulk density figure,^[9] so a "BS 3882" label on its own does not tell you how many litres are in a tonne. Ask for the product's own density.

For depth and quantity on a real bed or lawn, the topsoil calculator does the sum, and the raised bed calculator handles beds by size.

Gravel and Sand: Litres Per Tonne

Gravel: about 556 to 714 litres a tonne. Our gravel calculator runs on 1,500 kg per cubic metre for surface gravel, which gives about 667 litres to the tonne, and the range it works within is 1,400 to 1,600 kg per cubic metre. Published figures run heavier for rounded stone: British Sugar TOPSOIL lists shingle at 1.6 tonnes per cubic metre and pea gravel at 1.8, which is about 556 litres to the tonne.^[4] Wetter or denser stone sits at the heavy end and gives you fewer litres for your tonne.

MOT Type 1 sub-base is a different animal. British Sugar TOPSOIL lists it at 1.9 tonnes per cubic metre at light consolidation,^[4] and our sub-base calculator uses 2,100 kg per cubic metre, so a tonne of it is only around 476 to 526 litres. If you are pricing a driveway build-up, do not use a decorative gravel figure for the sub-base layer. The sub-base calculator keeps them separate.

Sand: about 625 litres a tonne for dry coarse sand. CJC Aggregates says dry sand generally weighs around 1,600 kg per cubic metre,^[5] and British Sugar TOPSOIL lists dry coarse sand at the same 1.6 tonnes per cubic metre, which is about 625 litres to the tonne.^[4]

Fine sand is the exception. British Sugar TOPSOIL lists dry fine sand at 1.2 tonnes per cubic metre, which is about 833 litres to the tonne.^[4] CJC also notes that sand weight varies with its type and moisture content, so a damp load from an open yard will not match a dry figure.^[5]

Bark and Wood Chip: Why the Number Jumps

Roughly 4,000 to 5,000 litres a tonne. Melcourt, a UK bark producer, gives ornamental bark mulch a bulk density of 200 to 250 grams per litre.^[6] That is about a seventh of the density of gravel, so the same weight fills seven times the space.

This is why bark is almost always sold in litres and gravel is almost always sold in tonnes or kilos. If a bark supplier quotes you a weight, ask for the litres, because a "tonne of bark" is a lorry-load, not a bag. For mulching depth and coverage, use the mulch calculator or the bark chippings calculator.

How Many Litres Is a Bulk Bag?

There is no standard bulk bag. That is the honest answer and it catches people out constantly when they compare two prices.

All six were read off the supplier's own product page on 1 October 2026. Suppliers change bag sizes without notice, so check the listing before you order. Two of the six are sold by weight with no volume stated at all, which makes a straight price comparison impossible unless you convert first.

How Many 40 Litre Bags Make a Tonne?

Working from the figures above:

• Topsoil at 670 to 830 litres a tonne: about 17 to 21 bags of 40 litres.
• Gravel at 556 to 714 litres a tonne: about 14 to 18 bags of 40 litres.
• Sand at about 625 litres a tonne (dry, coarse): about 16 bags of 40 litres, or about 21 for fine dry sand at 833 litres.
• Bark at 4,000 litres or more a tonne: 100 plus bags of 40 litres, which is why nobody sells bark by the tonne to a garden.

Each of those is the litres-per-tonne figure from the table divided by 40, so the same spread applies. Treat them as a sanity check on a quote, not a precise order.

One last thing on units. A tonne is metric, 1,000kg,^[7] and that is what UK suppliers sell in. A ton is an older imperial unit, about 1.016 tonnes in UK law,^[8] and a US ton is different again at 2,000 pounds.^[7] If a figure looks odd, check which one the page meant.

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