How much gravel or bark?

Close-up of grey-blue gravel chippings.

Short answer: Multiply the area in square metres by the depth in metres, then by 1.6 for tonnes of gravel or by 1,000 for litres of bark. Borders usually take 30 to 40mm of gravel or 50 to 75mm of bark. Add 10% for settling, or 15% on uneven ground.

By the Yard & Field team

Updated

Ordering too little means a second delivery charge; ordering too much leaves a bag on the drive. A short sum gets you close.

1. Measure the area

Multiply the length by the width, in metres, to get the area in square metres. For an awkward shape, split it into rectangles and add them up.

2. Choose a depth

Where Gravel or chippings Bark or mulch
Borders and beds 30 to 40mm 50 to 75mm
Paths and patios 40 to 50mm For a path, coarse wood chip: 75mm, or 100mm where it's walked daily, with edging
Drives 40 to 50mm of angular 14mm or 20mm gravel, not rounded pebbles, over a compacted sub-base, typically 100 to 150mm of MOT Type 1 Not suitable

These are rough guides. Larger stones need a deeper layer to cover the ground; smaller ones spread further.

3. Do the sum

Gravel and chippings (sold by weight)

area (m²) × depth (m) × 1.6 = tonnes

Stone weighs roughly 1.4 to 1.7 tonnes a cubic metre, depending on the type. A figure of 1.6 suits most decorative gravel; heavier stone such as basalt is nearer 1.7, so use the supplier's own figure if it gives one. For a path 10 metres long and 1 metre wide at 50mm deep: 10 × 0.05 × 1.6 = 0.8 tonnes.

Bark and mulch (sold by volume)

area (m²) × depth (m) × 1,000 = litres

For a 12 square metre border at 75mm deep: 12 × 0.075 × 1,000 = 900 litres.

Then add 10% to allow for settling, or 15% on uneven ground. A little left over is useful for topping up.

How far a bulk bag goes

Bulk bags of stone are sold by weight, often 800 to 850kg. At 50mm deep, a bag covers roughly 10 square metres; at 30mm, about 17. A bulk bag of bark is often a cubic metre (1,000 litres), but check the listing. A cubic metre covers about 20 square metres at 50mm, or 13 at 75mm.

Before it arrives

  • Lay a weed membrane under gravel. It keeps most weeds down and stops the stones sinking into the soil.
  • Edge paths and borders, so the gravel stays where you put it.
  • Bulk bags usually come by lorry and are left at the kerbside or on the drive. Make sure there's room, and check whether the lorry can reach.

See also: getting it to your garden.

Please note: this guide is general advice to help you choose, not professional or legal advice. Every garden and every product is different, so always follow the maker's instructions and check with your council or a qualified tradesperson if you're unsure.

Sources for this guide

The pages we checked this guide's facts against, so you can read them for yourself. A link here isn't a recommendation.