How many tons of gravel do I need?
Multiply the cubic yards by the weight of a cubic yard, about 1.35–1.55 US tons for loose gravel.
US tons = square feet × depth (in) ÷ 324 × 1.35–1.55
The weight comes from the US Army's earthmoving tables: loose gravel weighs 2,700–3,000 lb per cubic yard dry and 2,800–3,100 lb wet.[1] A New Mexico state table uses a single figure of 1.42 US tons per cubic yard for ¼–2 inch gravel,[2] near the middle of that range. UC Master Gardeners' rule of thumb, one ton covering 80–120 sq ft at 2 inches, agrees.[3]
| Area | 2 in | 3 in | 4 in | 6 in |
|---|---|---|---|---|
| 50 sq ft | 0.42–0.48 | 0.62–0.72 | 0.83–0.96 | 1.25–1.44 |
| 100 sq ft | 0.83–0.96 | 1.25–1.44 | 1.66–1.91 | 2.5–2.87 |
| 200 sq ft | 1.66–1.91 | 2.5–2.87 | 3.33–3.83 | 4.99–5.74 |
| 300 sq ft | 2.5–2.87 | 3.75–4.31 | 4.99–5.74 | 7.49–8.62 |
| 500 sq ft | 4.16–4.79 | 6.24–7.18 | 8.32–9.57 | 12.49–14.36 |
| 1,000 sq ft | 8.32–9.57 | 12.49–14.36 | 16.65–19.14 | 24.97–28.72 |
How many tonnes of gravel do I need?
Multiply the cubic meters by 1.60–1.84 tonnes per cubic meter, the same weight range converted to metric.[5]
tonnes = area (m²) × depth (cm ÷ 100) × 1.6–1.84
A 5 × 4 m gravel garden at 5 cm is 20 × 0.05 = 1 m³, so it needs about 1.6–1.8 tonnes.
| Area | 3 cm | 5 cm | 7.5 cm | 10 cm |
|---|---|---|---|---|
| 5 m² | 0.24–0.28 | 0.4–0.46 | 0.6–0.69 | 0.8–0.92 |
| 10 m² | 0.48–0.55 | 0.8–0.92 | 1.2–1.38 | 1.6–1.84 |
| 20 m² | 0.96–1.1 | 1.6–1.84 | 2.4–2.76 | 3.2–3.68 |
| 30 m² | 1.44–1.66 | 2.4–2.76 | 3.6–4.14 | 4.8–5.52 |
| 50 m² | 2.4–2.76 | 4–4.6 | 6–6.9 | 8–9.2 |
| 100 m² | 4.8–5.52 | 8–9.2 | 12–13.8 | 16–18.4 |
A metric tonne (1,000 kg) is about 10% heavier than a US ton (2,000 lb, 907 kg), so the same job is a slightly smaller number in tonnes.[5]
Bulk bags
A gravel bulk bag holds about one cubic meter and covers around 20 m² at 5 cm, according to the RHS,[4] which is exactly the volume math: 1 m³ ÷ 0.05 m = 20 m². Bag weights depend on the stone, so check the figure on the delivery note. The calculator lets you pick 500, 750 or 1,000 L bulk bags in metric mode to count how many you need.
Small bags varyThe RHS also says a 25 kg bag covers about 0.6 m² at 5 cm.[4] That implies a much lighter fill (about 830 kg per m³) than engineering tables give for loose gravel, so for small bags go by the coverage printed on the bag rather than by weight.
Depth for gravel gardens and paths
About 5 cm (2 in) for decorative gravel and paths.
The RHS bases its coverage figures on 5 cm (2 in),[4] and US guidance treats 2 inches as a practical minimum for paths.[3] Under paving, a compacted base of at least 100 mm (4 in) is the minimum for pedestrian areas and 150 mm (6 in) for residential driveways on well-drained soil.[6] The gravel depth guide collects the rest, and the paver base calculator handles compaction. For a quote in tons of another material, use the tons to yards calculator.
Gravel grades and weight
Grade changes the look more than the weight. The RHS groups decorative gravel into fine grades of 10 mm or less and chunkier grades of 20 mm or more.[4] Whatever the grade, weight per cubic meter varies with grain size, moisture content and degree of compaction, as the US Army's earthmoving tables point out.[1]
Frequently asked questions
How many yards in a ton of gravel?
About 0.64–0.74 cubic yards of loose gravel, which weighs 2,700–3,100 lb per cubic yard.[1]
How much does a ton of gravel cover?
About 104–120 sq ft at 2 inches deep, 70–80 sq ft at 3 inches and 52–60 sq ft at 4 inches.[1]
How many tons of gravel do I need for 100 square feet?
At 3 inches, 100 × 3 ÷ 324 = 0.93 cubic yards, about 1.25–1.44 US tons. At 4 inches, about 1.67–1.92 tons.
How many tonnes of gravel for 10 m²?
At 5 cm: 10 × 0.05 = 0.5 m³, or about 0.8–0.92 tonnes.
How much does a cubic meter of gravel weigh?
About 1.6–1.84 tonnes loose, from dry to wet.[1]
How much does a bulk bag of gravel cover?
A bag of about 1 m³ covers around 20 m² at 5 cm, according to the RHS.[4]
Sources
- FM 5-434 Earthmoving Operations, Tables 1-1 and 1-2 (material weights, swell and conversion factors)
- Conversion Factors for Construction Materials and Common Minerals (from BLM Handbook H-3890-1)
- Gravel Pathways in the Garden
- Gravel gardens
- NIST Handbook 44, Appendix C: General Tables of Units of Measurement
- Construction of Interlocking Concrete Pavements (PAV-TEC-002-22)