Sleeper raised bed calculator
A 2.4 × 1.2 m raised bed two sleepers high takes about 6 standard sleepers and 1.3 tonnes of topsoil to fill.
- Bed height
- 400 mm
- Topsoil to fill it
- 1.32 tonnes
- Soil volume
- 0.88 m³
A 2.4 × 1.2 m bed, 2 sleepers high (400 mm), using 2.4 m sleepers.
Allow one extra sleeper if your cuts don’t work out. Many people fill the bottom with cheaper subsoil or rubble.
Sleepers for common raised beds
Using 2.4 m sleepers, 200 × 100 mm.
| Bed size | 1 high | 2 high | 3 high | Soil (2 high) |
|---|---|---|---|---|
| 1.2 × 1.2 m | 2 | 4 | 6 | 0.6 t |
| 2.4 × 1.2 m | 3 | 6 | 9 | 1.3 t |
| 2.4 × 2.4 m | 4 | 8 | 12 | 2.9 t |
| 3.6 × 1.2 m | 4 | 8 | 12 | 2.0 t |
| 4.8 × 1.2 m | 5 | 10 | 15 | 2.8 t |
How we calculate this
Standard UK sleepers are 2.4 m long, 200 mm high and 100 mm thick. The long sides run the full length of the bed and the short sides fit between them, so we work out the total length of sleeper for each layer and divide by 2.4 m.
For the soil, we use the inside of the bed (taking off the sleeper thickness) and weigh topsoil at 1.5 tonnes per m³.
Questions people ask
What size are garden sleepers?
Most UK garden sleepers are 2.4 m long, 200 mm high and 100 mm thick. Some are 250 mm high, so check before you buy.
How do I fix sleepers together?
Long timber screws or coach screws through the corners, often with metal brackets inside. Stagger the joints on taller beds, like brickwork, for strength.
What do I fill a raised bed with?
Good-quality topsoil mixed with compost. For deep beds you can fill the bottom with cheaper subsoil or rubble to save on topsoil.
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