Raised Bed Soil Calculator
How much soil fills a raised garden bed? Enter the inside length, width, and fill depth to get litres and cubic metres, and the count of standard 25 L bags.
Your results
Worked example
A common Canadian raised bed is 2.4 m by 1.2 m (about 8 ft by 4 ft), filled 30 cm deep:
- Volume: 2.4 m × 1.2 m × 0.30 m = 0.864 m³
- In litres: 0.864 × 1,000 = 864 L
- In bags: 864 ÷ 25 L per bag = 34.56, so 35 bags
At 35 bags, compare the bag total against a bulk cubic yard bag or a yard delivery: beds this size usually cross the point where bulk soil is cheaper, and one bulk bag holds about 765 L.
How this calculator works
The calculator uses the inside dimensions of the bed, because boards take up real space: a bed built from 38 mm lumber loses about 8 cm of length and width to the frame. Soil also settles after watering, typically 5 to 10 percent, so filling to the brim and topping up after the first week is normal practice and is not included in the count above.
Common questions
Can I fill the bottom with branches and leaves first?
Yes, a layer of logs, branches, and leaves in the bottom third of a deep bed (often called hugelkultur) cuts the soil volume you need to buy. Subtract that layer from the depth before using this calculator.
What soil mix should a raised bed get?
A common blend is about 60 percent topsoil, 30 percent compost, and 10 percent aeration material such as peat or coir. Whatever the blend, order by total volume from this page and split it by those proportions.
Estimates only. Results are provided for planning purposes and are based on the bed dimensions and bag size stated on this page. Soil settles after filling and watering. Mississippi Maple accepts no liability for purchase decisions made using this calculator.