How Much Topsoil for a Raised Bed?

Raised beds need to be filled from scratch — usually 10–12 inches deep. Here's exactly how many bags or cubic yards of topsoil you need for any raised bed size.

The quick formula

Volume (cu ft) = Length × Width × Depth (all in feet)

Cu yd = Volume (cu ft) ÷ 27

40 lb bags = Volume (cu ft) ÷ 0.75, rounded up

Raised bed topsoil by size (at 12 inches deep)

Bed size	Volume (cu ft)	Cu yards	40 lb bags
2 × 4 ft	8 cu ft	0.30 cu yd	11 bags
4 × 4 ft	16 cu ft	0.59 cu yd	22 bags
4 × 8 ft	32 cu ft	1.19 cu yd	43 bags
4 × 12 ft	48 cu ft	1.78 cu yd	64 bags
4 × 16 ft	64 cu ft	2.37 cu yd	86 bags
6 × 8 ft	48 cu ft	1.78 cu yd	64 bags

Volume by depth (4×8 raised bed)

Depth	Volume	Cu yards	40 lb bags
6 inches	16 cu ft	0.59	22 bags
8 inches	21.3 cu ft	0.79	29 bags
10 inches	26.7 cu ft	0.99	36 bags
12 inches	32 cu ft	1.19	43 bags
18 inches	48 cu ft	1.78	64 bags

Bags vs. bulk for raised beds

Under 2 cu yd (2 beds): bags are convenient — no delivery needed
2+ cu yd: bulk topsoil delivery saves 30–50% vs. bags
A cubic yard of bulk topsoil costs roughly $30–$60 delivered, vs. $1.50–$2.50 per bag

Recommended raised bed soil mixes

Mix	Ratio	Good for
Straight topsoil + compost topdress	100% topsoil + annual compost	Established beds
Topsoil + compost blend	50/50	New beds, good value
Mel’s Mix	1/3 topsoil + 1/3 compost + 1/3 perlite	High-yield veggie beds

Use the Topsoil Calculator and enter your bed’s internal dimensions. For multiple beds, use the Irregular shape option to add them together.

Frequently Asked Questions

How many cubic yards of topsoil do I need for a 4×8 raised bed?

A standard 4×8 ft raised bed that is 12 inches deep needs 32 cubic feet, which equals 1.19 cubic yards. That is about 43 bags of 40 lb topsoil. Most gardeners also mix in compost — a 50/50 mix means about 0.6 yards each of topsoil and compost.

How deep should a raised bed be filled with topsoil?

For most vegetables, fill raised beds to 10–12 inches. Root vegetables like carrots and parsnips benefit from 18 inches of loose, deep soil. Shallow-rooted plants (lettuce, herbs) do fine with 6–8 inches.

What mix should I use for a raised bed?

A popular raised bed mix is 1/3 topsoil, 1/3 compost, and 1/3 coarse sand or vermiculite (the "Mel's Mix" variant). For a pure topsoil fill, choose screened loam topsoil and add compost on top each season.

How many 40 lb bags of topsoil fill a 4×4 raised bed?

A 4×4 ft raised bed at 12 inches deep holds 16 cubic feet (0.59 cu yd). That takes about 22 bags of 40 lb topsoil (each yields ~0.75 cu ft).