How much soil, gravel or concrete do I need? Square metres to cubic metres and tonnes

Area times depth gives the volume, and volume times the weight per cubic metre gives the tonnes. 10 square metres of gravel in a 5 cm layer is 0.5 cubic metres, that is 500 litres, and weighs about 0.75 tonnes. The same calculation applies to soil, sand, crushed stone and concrete, with a different weight per cubic metre. Here are the tables and the common cases: the raised bed, the driveway and the slab.

Cubic metres from area and depth

Depth is usually given in centimetres. Divide it by 100 and multiply by the area in square metres for cubic metres. A cubic metre is 1,000 litres.

Add 10 to 15 percent for compaction and waste when ordering. The cubic metres to litres converter turns it into bags, which are sold by the litre.

What does a cubic metre of soil, gravel and concrete weigh?

The weight depends on the material, how compacted it is and how wet it is. The suppliers’ own reference figures (Swedish suppliers, all in metric):

Bagged potting soil is light because it is peat-based and airy; soil delivered by the load from a gravel company weighs twice as much or more. A wet load weighs more still. Convert tonnes with the tonnes to kilograms converter.

How much soil in a pallet collar bed?

A pallet collar of 120 by 80 cm and 20 cm high holds about 200 litres, and Swedish garden centres count 3 to 4 bags of 50 litres per collar. The inside dimensions are a little smaller than the outside, and the soil settles when watered, so count on 4 bags rather than 3. Two collars stacked take 400 litres.

A 40 litre bag of peat-free potting soil weighs about 22 kg according to Rölunda, so just over half a kilogram per litre. Peat-based soil is lighter. Four 50 litre bags for one collar is then around 100 kg of soil.

How much gravel for the driveway?

A top layer of gravel on a driveway is often laid 5 cm thick. A driveway of 3 by 10 metres, 30 square metres, then needs 1.5 cubic metres, which weighs about 2.3 tonnes. A base layer underneath is thicker, 10 to 20 cm, and is calculated the same way. Gravel companies sell by the tonne or by the cubic metre; at 1.5 tonnes per cubic metre you can switch between them.

How much concrete do I need?

A 25 kg bag of dry concrete mix gives about 12.5 litres of finished concrete, according to Finja. A cubic metre is 1,000 litres, so it takes 80 bags, 2 tonnes of dry mix, per cubic metre. Beyond a few hundred litres, ready-mixed concrete from a truck is usually easier. Footings and small slabs are calculated as volume: a slab of 2 by 3 metres and 10 cm thick is 0.6 cubic metres, so 48 bags.

The number of bags is based on 12.5 litres per bag and rounded up. Other brands yield slightly differently, so read the bag.

Sources: Snabbgrus, quantity calculator for Hasselfors lawn soil (1.30 t/m³); Gårda Johan, weight per cubic metre of crushed stone and driveway gravel; Heidelberg Materials, technical properties of concrete; Finja, Grovbetong 25 kg; Blomsterlandet, growing in pallet collars; bag weight from Rölunda’s product sheet for peat-free soil 40 l. All in Swedish, fetched 2026-09-27. The volumes are calculated from area and depth.