Multiply cubic metres by the material’s density in tonnes per m³: 4 m³ of crushed stone × 1.78 ≈ 7.1 tonnes. Most bulk aggregates fall between 1.6 and 2.0 t/m³, with sand and crushed stone near 1.78.
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M³ to Tonnes — Converting Metric Volume to Weight
Metric projects speak cubic metres on the plans and tonnes on the invoice, and the bridge between them is the same density logic as the imperial world — just with friendlier numbers. Tonnes = m³ × density in t/m³, and for crushed stone that density is about 1.78 tonnes per cubic metre. A 4 m³ trench therefore takes roughly 7.1 tonnes. This converter accepts either side: enter cubic metres to get tonnes, or a tonnage quote to see the volume it fills.
A cubic metre is a big unit — 35.3147 cubic feet, or about 1.31 cubic yards — so metric orders always look deceptively small next to imperial ones. A “10-yard” American driveway order is only 7.6 m³, and a single m³ of crushed stone already weighs more than most small trailers are rated to carry.
How Many Tonnes per Cubic Metre?
| Material | t per m³ | 5 m³ = | 10 tonnes = |
|---|---|---|---|
| Lava rock | 0.77 | 3.9 t | 13.0 m³ |
| Topsoil | 1.31 | 6.5 t | 7.6 m³ |
| Pea gravel | 1.60 | 8.0 t | 6.3 m³ |
| Gravel | 1.66 | 8.3 t | 6.0 m³ |
| Crushed stone | 1.78 | 8.9 t | 5.6 m³ |
| Sand | 1.78 | 8.9 t | 5.6 m³ |
| Crusher run | 1.84 | 9.2 t | 5.4 m³ |
| Limestone | 1.84 | 9.2 t | 5.4 m³ |
| Riprap | 1.96 | 9.8 t | 5.1 m³ |
Contractors often shortcut this whole table with “2 tonnes per cube.” It’s a serviceable ceiling — nothing common exceeds it — but it overshoots most aggregates by 8–15%, and on a 30 m³ civil job that’s four or five tonnes of phantom material in the budget. Use the shortcut to sanity-check a quote; use the real density to write the order.
Keeping Metric and Imperial from Colliding
- A tonne is not a ton. The metric tonne is 1,000 kg — 2,204.6 lb — while the US short ton is 2,000 lb. They differ by 10%, which is exactly the size of a typical waste allowance, so a units mix-up silently erases your safety margin.
- Watch for “tons” on metric paperwork. Suppliers in metric countries sometimes write “ton” while meaning tonne. If a document mixes kilograms and “tons,” assume tonnes; if it mixes pounds and “tons,” assume short tons — and confirm either way.
- Convert volume before comparing quotes. One m³ is 1.31 yd³, so a price per cubic metre must be divided by 1.31 before it can stand next to a price per cubic yard.
- Bulk bags are a metric-friendly unit. The common one-tonne bulk bag holds about 0.6 m³ of crushed stone — a useful mental checkpoint when a quote arrives in bags rather than loose tonnes.
Working the other direction — from a known weight back to the space it occupies — the tons to cubic yards calculator handles both tons and tonnes. For imperial-first projects, the cubic yards to tons calculator is this tool’s mirror image.
Frequently Asked Questions
How many tonnes is 1 m³ of crushed stone?
About 1.78 tonnes. Gravel runs lighter at roughly 1.66 t/m³, dense crusher run and limestone reach 1.84, and riprap tops the common materials near 1.96 tonnes per cubic metre.
Is the "2 tonnes per m³" rule of thumb safe to use?
It overestimates most aggregates by 8–15%, which errs on the safe side for ordering but inflates budgets. For anything beyond a rough sanity check, use the actual material density — the gap on a 20 m³ job is several tonnes.
What is the difference between a tonne and a US ton?
A metric tonne is 1,000 kg (2,204.6 lb); a US short ton is 2,000 lb. The tonne is about 10% heavier, so quotes and calculators must not mix them — this tool works in tonnes and shows the US-ton equivalent.
How does m³ relate to cubic yards and cubic feet?
One cubic metre is 35.3147 cubic feet, or about 1.31 cubic yards. If your supplier prices in yards but your plans are metric, multiply m³ by 1.31 before comparing quotes.