What this calculator does
Converting m3 to tonnes is not a fixed conversion the way converting metres to feet is. A cubic metre of water weighs about a tonne, a cubic metre of dry sand weighs close to 1.6 tonnes, and a cubic metre of loose mulch can weigh well under half a tonne. The only way to convert m³ to tonnes correctly is to know the density of the specific material involved.
This calculator converts m3 to tonnes and tonnes to m3 in either direction, with the density left as a free field you set yourself rather than baked in. As a rough starting point, general aggregate such as sand, gravel or crushed rock commonly runs somewhere around 1.5 to 1.8 tonnes per m³, but that varies by material, moisture content and how tightly it is packed, so check the actual density of what you are ordering or moving before relying on a number here.
The formula
Multiply the volume in cubic metres by the density in tonnes per cubic metre to get the weight in tonnes. To go the other way, divide the weight in tonnes by the density to recover the volume in cubic metres. Both directions use the same density figure, so getting that number right matters more than the arithmetic itself.
| Term | Meaning |
|---|---|
| Density | Weight per unit volume for the specific material, in tonnes per cubic metre (t/m³). |
| m³ to tonnes | Volume × density = weight. |
| Tonnes to m³ | Weight ÷ density = volume. |
The inputs explained
| Field | What to enter |
|---|---|
| Convert | Choose which way you are converting. |
| Amount to convert | The amount you already have, in cubic metres or in tonnes depending on the direction chosen. |
| Density (aggregate such as sand, gravel or crushed rock typically runs about 1.5 to 1.8 t/m³, edit for your material) (t/m³) | The density of the specific material, in tonnes per cubic metre. Do not leave this at the default unless it genuinely matches your material. |
When to use it
Ordering aggregate by weight or by volume
Quarries and landscape suppliers sometimes quote in tonnes and sometimes in cubic metres. Converting between the two with the supplier's stated density, rather than a generic assumption, avoids over- or under-ordering.
Working out a truck or trailer load
Vehicle payload limits are almost always stated in weight, while the space available is measured in volume. Converting the volume you need into tonnes checks it against the payload before loading.
Estimating a delivery cost priced per tonne
When a job is planned in cubic metres, such as a garden bed or a footpath base, converting that volume to tonnes at the correct density gives the weight a per-tonne delivery price is actually based on.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How many tonnes is 1m3, at different densities?
A fixed 1 m³, shown at a range of densities typical of common bulk materials.
Converting m3 to tonnes across a range of volumes
A fixed density of 1.6 t/m³, a common midpoint figure for aggregate, across a range of volumes.
Questions
How many tonnes is 1m3 of aggregate?
It depends on the material, but general aggregate such as sand, gravel or crushed rock is commonly quoted around 1.5 to 1.8 tonnes per m³. Confirm the exact figure with the supplier for the specific product, since moisture content and how loosely or tightly it is packed both move the number.
Why is there no single m3 to tonne conversion factor?
Tonnes measure weight and cubic metres measure volume, and the relationship between the two, density, is different for every material. Converting steel, water, sand and mulch all use the same formula but very different density figures, so no single factor applies across materials.
Where do I find the density of my material?
Suppliers of aggregate, soil, mulch and similar bulk materials usually quote a density, often as tonnes per cubic metre or kilograms per cubic metre, either on the product page or the delivery docket. That figure, not a generic assumption, is the one to enter here.
Does moisture change the conversion?
Yes. Wet sand or wet soil weighs noticeably more per cubic metre than the same material dry, because the water adds weight without adding much volume. A density figure quoted for dry material can understate the actual weight of a wet load.
For the weight of a solid concrete slab or footing at a chosen density, see the concrete weight calculator. For a flat glass pane, see the glass weight calculator.