Raised Bed Soil Calculator
Litres of soil or compost needed to fill a raised bed or planter, with the number of bags and the cost.
Results
What this tool does
Raised beds swallow far more soil than they look like they will: a modest 2.4 by 1.2 metre bed thirty centimetres deep takes over eight hundred litres, which is a dozen large bags or the best part of a bulk-bag delivery. Working it out first is the difference between one trip to the garden centre and three.
Formula
volume = length x width x depth ; bags = volume / bag capacity
Variables
| Symbol | Meaning | Unit |
|---|---|---|
ll | Length | cm |
ww | Width | cm |
dp | Depth | cm |
bg | Bag size | L |
pb | Price per bag | — |
VL | Volume | L |
VM | Volume | m³ |
BG | Cement bags | — |
CO | Total cost | — |
AR | Area | m² |
Worked example
- Length240 cm
- Width120 cm
- Depth30 cm
- Bag size70 L
- Price per bag6.5
- Volume864.0 L
- Volume0.8640 m³
- Cement bags13
- Total cost84.50
- Area2.880 m²
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The calculation runs at full precision and only the display is rounded. If you copy an intermediate value and retype it, small differences can appear.
Frequently asked questions
Should I allow for the soil settling?
Yes. Bagged compost is sold loose and fluffed up, and it typically loses a tenth to a fifth of its volume in the first season as it settles and as the organic fraction breaks down. Buying one extra bag is cheaper than a second delivery, and topping up every spring is normal practice rather than a sign that anything went wrong.