🪴 Raised Bed Soil Calculator
Enter your raised bed's length, width and depth to get the volume of soil to buy — in litres, cubic feet and yards, and the number of bags.
Soil volume
906 L
0.906 m³ · 32 ft³ · 1.19 yd³
Bags needed
19
Cubic yards
1.19
Volume = length × width × depth. Bulk soil is far cheaper than bags past about a cubic metre (≈ 1.3 yd³). A common raised-bed mix is roughly ⅓ topsoil, ⅓ compost, ⅓ aeration (e.g. perlite). 🔒 In your browser.
How the raised bed soil calculator works
The volume of soil is length × width × depth. The tool converts your bed dimensions into litres, cubic metres, cubic feet and cubic yards, and divides by your bag size to estimate the number of bags. For depth it uses centimetres or inches, since beds are shallow relative to their footprint.
Bulk soil delivery is far cheaper than bags once you need more than about a cubic metre (≈ 1.3 cubic yards). A popular raised-bed recipe is roughly one-third topsoil, one-third compost and one-third aeration (such as perlite or coarse sand). Fill a little proud, as soil settles.
Frequently asked questions
How much soil do I need for a raised bed?
Multiply length × width × depth. An 8 × 4 ft bed filled 12 in deep is 32 ft³ (about 906 litres, or 1.2 cubic yards). Enter your dimensions and the tool gives the volume and bag count.
How many bags of soil fill a raised bed?
Divide the volume by the bag size. A 906-litre bed needs about 18 fifty-litre bags. For large beds, bulk soil is much cheaper than bags — the tool shows both the volume and bag estimate.
What is the best soil mix for a raised bed?
A common mix is about one-third quality topsoil, one-third compost for nutrients, and one-third material for drainage and aeration (perlite, coarse sand or composted bark). Adjust to your plants and local soil.
How deep should a raised bed be?
At least 15–20 cm (6–8 in) for most vegetables, and 30 cm (12 in) or more for root crops and to reduce watering. Deeper beds hold moisture better and give roots room.
How much soil for a round or odd-shaped planter?
For a round pot, volume ≈ π × radius² × depth. This tool handles rectangular beds; for cylinders, calculate the area separately and multiply by the depth.