How many bags of gravel are in a tonne?
Last reviewed 1 July 2026
Short answer
Forty 25 kg handy bags make a tonne. UK bulk bags are usually filled to around 850 kg despite being sold as 'one tonne bags', so a tonne is roughly 1.2 bulk bags. In the US, gravel is normally sold by volume rather than weight — a cubic yard of gravel weighs about 1.35 US tons.
Work it out for your project with the gravel calculator →
The straightforward conversions
| Bag size | Bags per tonne | Bags per cubic metre (at 1,600 kg/m³) |
|---|---|---|
| 10 kg | 100 | 160 |
| 20 kg | 50 | 80 |
| 25 kg (UK handy bag) | 40 | 64 |
| 50 lb (22.7 kg, US) | 44 | 70 |
| Bulk bag at 850 kg | 1.18 | 1.88 |
| Bulk bag at 1,000 kg | 1.00 | 1.60 |
What a UK bulk bag actually holds
This is where most of the confusion lives. UK merchants call them 'one tonne bags', but the fill weight is set by the bag's safe working load and by how the material is loaded, and in practice most aggregate bulk bags contain 800–900 kg.
At 850 kg and 1,600 kg/m³ that is about 0.53 m³ — a little over half a cubic metre. If you ordered assuming a full tonne and 0.63 m³, you are about 15% short before you have started.
Topsoil bulk bags are different again: they are usually sold by volume, typically 0.7–0.8 m³, because soil density varies so much with moisture.
Important: Ask for the fill weight, not the bag name
When bags stop making sense
Handy bags are convenient up to about 20 bags — half a tonne. Beyond that you are paying a substantial premium for the packaging and doing a lot of lifting: 40 bags is a tonne of 25 kg lifts.
Bulk bags work well from about half a tonne to four or five tonnes. Above that, loose tipped material is usually cheaper per tonne, provided you have somewhere for the driver to tip it and are prepared to barrow it.
Remember that bulk bags need to be lifted off the lorry. Confirm the delivery vehicle has a crane or forklift and that it can get close enough to where you want the bag.
Working the other way
To go from an area to a bag count: area × depth × density ÷ bag weight, then round up.
A 15 m² path at 50 mm in 20 mm gravel is 0.75 m³, which is 1,200 kg — 48 handy bags, or 1.4 bulk bags, so two bulk bags. Two bulk bags gives you 1,700 kg against 1,200 kg needed, which is a lot of spare; this is exactly the situation where loose delivery of 1.5 tonnes would suit better if the supplier allows it.
Safety notice: Material planning only