Raised Bed Soil Calculator
Work out exactly how much soil to buy to fill your raised beds or planters — no half-empty beds, no overspend.
Last reviewed 2026-06-06
Filling a raised bed always takes more soil than it looks — and bagged soil is expensive, so over-ordering hurts. This calculator gives you the precise volume and the number of bags (or cubic yards) for any number of beds at once.
Enter the inside dimensions of one bed, how deep you want to fill it, and how many identical beds you have. We multiply it all out and suggest a soil mix that actually grows healthy plants.
How to use the Raised Bed Soil Calculator
- Measure the inside length and width of your bed (not the outer frame).
- Decide your fill depth — 8–12 inches (20–30 cm) suits most vegetables.
- Enter how many identical beds you are filling.
- Read the total volume, per-bed volume and number of bags.
Frequently asked questions
How much soil do I need for a raised bed?
Multiply the bed’s length × width × depth. For example, a 4 × 8 ft bed filled 10 inches deep needs about 27 cubic feet — roughly one cubic yard, or eighteen 1.5 cu ft bags. Use the calculator above to get your exact figure.
What is the best soil mix for raised beds?
A popular, forgiving mix is about 60% quality topsoil, 30% compost and 10% aeration such as perlite or coarse sand. The compost feeds plants while the topsoil gives structure and the aeration prevents compaction.
Should I fill a raised bed completely with soil?
For deep beds you can fill the bottom third with cheaper bulk material — coarse compost, leaves, or small branches (a “hügelkultur” base). The top 8–12 inches, where roots live, should be good soil mix.
Why does the soil level drop after a few weeks?
Fresh soil and compost are fluffy and settle as they are watered and as organic matter breaks down. Overfill slightly at planting time and top up with compost after a few weeks.