Raised Bed Soil Calculator

How much soil does a raised bed need?

The soil for a raised bed is just a box of volume: length × width × depth. Do the math in feet and you get cubic feet directly. This calculator converts your inches or feet, multiplies the three dimensions, and then translates that volume into the three units you actually shop with: cubic feet, cubic yards, and standard 1.5 cubic foot bags.

Cubic yards matter once you go big. There are 27 cubic feet in a cubic yard, so a single 4×8 bed filled a foot deep is about 32 cubic feet — roughly 1.2 yards. Past a yard or two it is almost always cheaper to order bulk soil delivered than to haul dozens of bags.

Bags vs. bulk

Bagged soil is sold most commonly in 1.5 cubic foot bags, which is what the bag count here assumes. We always round up, because you cannot buy a partial bag and soil settles after watering. If your store sells 2 or 3 cubic foot bags, divide the cubic-foot result by that size instead.

How to use it

1. Enter the length, width, and soil depth of your bed.
2. Pick whether those numbers are in feet or inches.
3. Set how many identical beds you are filling.
4. Read the cubic feet, cubic yards, and bag count — they update as you type.

These figures are planning estimates, not professional landscaping advice. Buy a little extra to allow for settling.

FAQ

How deep should the soil be?

Most vegetables are happy with 8–12 inches. Root crops and deep-rooted plants prefer the full 12 inches or more.

Do I need to fill the whole bed with soil?

No. Many gardeners fill the bottom third with logs, sticks, or compost (hugelkultur). Just reduce the depth you enter to match the true soil layer.

Why round bags up?

Soil compresses as it settles and after the first watering, so a rounded-up count leaves a useful buffer instead of a half-empty bed.

How many bags in a cubic yard?

A cubic yard is 27 cubic feet, which is 18 of the 1.5 cubic foot bags — a good moment to consider bulk delivery.