Gravel, Mulch & Soil Calculator
Volume, tonnes and bags of gravel, mulch, topsoil or sand for any area and depth.
About this tool
Choose the shape of the area, enter its size and the depth you want, and pick the material and bag size. The calculator shows the area, the volume in cubic metres, cubic yards or cubic feet, the weight in tonnes or US tons, and the number of bags. An extra percentage covers settling and compaction.
How much gravel, mulch or soil you need
Volume is area ร depth. A 5 ร 3 m path covered 5 cm deep needs 0.75 mยณ, or 0.825 mยณ with 10% extra for settling. At a typical 1.6 tonnes per cubic metre for gravel that weighs about 1.32 tonnes, or 53 bags of 25 kg. Densities differ widely by material. Gravel and sand are around 1.5โ1.6 t/mยณ, topsoil about 1.3, compost about 0.6 and bark mulch only about 0.4. That is why suppliers sell gravel by weight but mulch by volume, and why this calculator shows both. Typical depths are 5 cm (2 in) for a gravel path, 7โ10 cm (3โ4 in) of surface gravel over a compacted base for a driveway, 5โ8 cm for mulch beds and 15โ30 cm of topsoil for a new lawn or raised bed. Honest limits: densities change with moisture and grading, so check your supplier's figure, and bulk bags vary in size. The concrete calculator handles slabs and footings, the area calculator measures irregular beds and the volume calculator covers other shapes.
Frequently asked questions
How much does a cubic metre of gravel weigh?
Typically about 1.5โ1.7 tonnes, depending on stone size and moisture. The calculator uses 1.6 t/mยณ for general gravel.
How many bags of gravel do I need?
Divide the weight by the bag weight. 0.825 mยณ of gravel weighs about 1,320 kg, which is 53 bags of 25 kg.
How deep should gravel be for a path?
About 5 cm (2 in) of gravel over a compacted, weed-suppressed base. Driveways need a deeper sub-base.
Is my data saved?
No. The calculation runs in your browser and nothing is stored or sent.