How much soil do I need for a 4x8 raised bed?

Multiply length × width × depth in feet. A 4 × 8 ft bed 12 inches deep is 32 cubic feet — 1.19 cubic yards, or 22 bags of 1.5 cu ft. At 6 inches deep it is half that: 16 cubic feet.

How many bags of soil for a raised bed?

Divide the bed's cubic feet by the bag size and round up. Two 8 × 4 ft beds at 12 inches hold 64 cubic feet, which is 43 bags of 1.5 cu ft or 32 bags of 2 cu ft. Above about a cubic yard, bulk delivery is often worth pricing.

What is the best soil mix for raised beds?

A popular recipe is Mel Bartholomew's Square Foot Gardening mix: one third compost, one third peat moss (or coconut coir), one third coarse vermiculite, by volume. For 64 cubic feet that is about 21.3 cubic feet of each.

How deep should a raised bed be?

Six inches suits lettuce and herbs, and 12 inches suits most vegetables. Deeper beds cost more to fill; if the bed sits on soil, loosen the ground beneath and let deep roots grow down into it.

How many cubic feet are in a cubic yard of soil?

27 — a cubic yard is 3 × 3 × 3 feet. So 64 cubic feet is 2.37 cubic yards.

Sand, Soil & Mulch

Raised Bed Soil Calculator

A raised bed holds more soil than it looks like: an 8 × 4 ft bed 12 inches deep takes 32 cubic feet, over a cubic yard. Enter the bed size, depth and how many you are filling for the total in cubic feet and yards, the bag count at the size you are buying, and the three-way Square Foot Gardening mix split into equal parts.

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Prices and savings as of Sep 30, 2026, 4:34 AM UTC. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.

Worked example: two 8 × 4 ft beds, 12 in deep

Step	Working	Result
One bed	8 × 4 × 1 ft	32 ft³
Two beds	32 × 2	64 ft³ = 2.37 yd³
1.5 cu ft bags	64 ÷ 1.5	43 bags
Equal-thirds mix	64 ÷ 3	21.3 ft³ each of compost, peat or coir, vermiculite

The mix

The equal-thirds blend is Mel Bartholomew's "Mel's Mix" from Square Foot Gardening: one third blended compost, one third peat moss (coconut coir is the common substitute) and one third coarse vermiculite, measured by volume rather than weight. It is light and drains well; many gardeners instead fill with a bagged raised-bed blend or screened topsoil mixed with compost — the volume is the same either way.

Saving soil in deep beds

Beds on open ground only need bought soil in the root zone: loosen the ground beneath and fill the top 6–12 inches.
Beds on a patio or hard surface need the full depth, plus a drainage gap at the base.
New soil settles over the first season; top up rather than overfilling on day one.

Bulk soil comes by the cubic yard — the topsoil calculator compares bulk and bags, and the pea gravel calculator sizes the paths between beds.

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Frequently asked questions

How much soil do I need for a 4x8 raised bed?: Multiply length × width × depth in feet. A 4 × 8 ft bed 12 inches deep is 32 cubic feet — 1.19 cubic yards, or 22 bags of 1.5 cu ft. At 6 inches deep it is half that: 16 cubic feet.
How many bags of soil for a raised bed?: Divide the bed's cubic feet by the bag size and round up. Two 8 × 4 ft beds at 12 inches hold 64 cubic feet, which is 43 bags of 1.5 cu ft or 32 bags of 2 cu ft. Above about a cubic yard, bulk delivery is often worth pricing.
What is the best soil mix for raised beds?: A popular recipe is Mel Bartholomew's Square Foot Gardening mix: one third compost, one third peat moss (or coconut coir), one third coarse vermiculite, by volume. For 64 cubic feet that is about 21.3 cubic feet of each.
How deep should a raised bed be?: Six inches suits lettuce and herbs, and 12 inches suits most vegetables. Deeper beds cost more to fill; if the bed sits on soil, loosen the ground beneath and let deep roots grow down into it.
How many cubic feet are in a cubic yard of soil?: 27 — a cubic yard is 3 × 3 × 3 feet. So 64 cubic feet is 2.37 cubic yards.