How many litres in a cubic metre?

There are 1,000 litres in one cubic metre. So 0.5 m³ equals 500 litres.

How big is a bulk bag?

A standard bulk bag (also called a tonne bag or dumpy bag) holds approximately 0.85 cubic metres of material.

It depends on the material. Topsoil weighs roughly 1.4 tonnes per m³, gravel about 1.8 tonnes per m³, and sand about 1.6 tonnes per m³.

Common depths: mulch 50-75mm, gravel paths 40-50mm, topsoil for lawns 150mm, raised beds 200-300mm.

1 cubic metre = 1,000 litres. So 0.5 m³ = 500 litres. This conversion is useful for ordering compost, soil, and gravel in practical quantities.

Work out volumes for any garden project in cubic metres or litres.

Shape

Length

Width

Depth

Rectangular: Volume = Length x Width x Depth. Cylindrical: Volume = pi x Radius² x Depth.

Tapered: uses the prismoidal formula to account for sloping sides (assumes 80% base dimensions).

Results are shown in cubic metres, litres, and approximate number of standard 0.85 m³ bulk bags.

Calculate the area of rectangular, circular, and triangular garden spaces.

Calculate garden slope gradient, angle, and drainage requirements.

Work out the area of curved or irregular garden borders.

Calculate area and edging for circular or semi-circular flower beds.

Estimate the area of irregularly shaped garden spaces.

Last updated: February 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.