Gravel Calculator

How to use this calculator

1. Measure the length and width of the area.
2. Set the depth: 2–3 in (5–7.5 cm) for decorative paths, 4–6 in (10–15 cm) for driveway surfaces over a compacted sub-base.
3. Choose the material — density differs between pea gravel, crushed stone and sub-base.
4. If your supplier quotes a density, enter it under Advanced for a more accurate weight.

Method & assumptions

Volume = Length × Width × Depth × (1 + waste %)
Weight (t) = Volume (m³) × Density (t/m³)
Short tons = tonnes × 1.1023

Density

loose bulk density of the material; varies with grading and moisture

Short ton

2,000 lb (US)

Tonne

1,000 kg (metric)

Assumptions & limits

• Densities are typical loose values; compacted sub-base needs more material for the same finished depth.
• Waste covers compaction and uneven sub-grade.

Rounding: purchase quantities are always rounded up to whole bags, boxes, sheets or bundles. See our methodology.

Worked examples

In depth: gravel planning notes

Density and why gravel is sold by weight

Gravel and crushed stone are usually sold by the ton or tonne, but you need a volume to fill a path or base. The link is density, which depends on the stone type, size and how well graded it is. Typical figures are about 1.4–1.7 tonnes per cubic metre (roughly 1.2–1.4 short tons per cubic yard) for most aggregates. Our default of 1.6 t/m³ suits common crushed stone; enter your supplier's figure if they give one.

Compaction matters too. A sub-base of crushed stone such as MOT Type 1 or road base compacts by 15–20%, so you need more loose material than the finished depth suggests. Decorative pea gravel and river rock do not compact much, so a small allowance is enough.

Depth by use

A decorative path or border needs about 2 in (50 mm) of gravel over a weed membrane. A walking path on soft ground benefits from 3–4 in (75–100 mm) of compacted sub-base under the top layer. Patio and paver bases are usually 4–6 in (100–150 mm). Driveways need much more: 6–12 in (150–300 mm) of compacted base depending on soil and traffic, with a decorative layer on top. Drainage trenches and French drains are filled to the depth of the trench.

For large jobs, a bulk delivery by tipper truck is usually the cheapest option; for small paths, bags of 0.5 cu ft or 20–25 kg, or a 0.7–1 m³ bulk bag, are easier to handle. Check that the delivery vehicle can reach your drop point and protect the driveway surface if necessary.

For anything that will carry vehicles or retain soil, follow local guidance on base depth and drainage; this calculator estimates materials, not structural adequacy.

Edging and membranes

Gravel migrates. Edging made from timber, steel, brick or concrete keeps it in place and stops it spreading into lawns. A permeable weed membrane under decorative gravel reduces weeds and stops stones sinking into soil; it is not needed under a compacted sub-base that will be covered by pavers or concrete.

Tips & common mistakes

• Lay a geotextile membrane under decorative gravel to stop it sinking into soil.
• Angular crushed stone locks together; rounded pea gravel moves underfoot — choose by use.
• Compact sub-base in layers of no more than ~4 in (10 cm).

Sources

1. National Stone, Sand & Gravel Association — checked 2026-10; verify before launch
2. Vulcan Materials – aggregate products — checked 2026-10; verify before launch
3. NIST – mass and volume conversions — checked 2026-10; verify before launch

Default values (bag yields, coverage rates, densities) are typical figures from manufacturer literature. Always check the label on the product you buy.

Cite or embed this calculator

DIYCalcLab. “Gravel Calculator.” Oct 18, 2026. https://diycalclab.com/landscaping/gravel-calculator/

An embeddable version for blogs and contractor sites is planned.