Easy Garden Calc

How much soil for a 4×4 raised bed?

Short answer

A 4 × 4 ft raised bed 12 inches tall, filled to 1 inch below the rim, holds 14.7 cubic feet of soil. With 10% extra for settling, buy 16.1 cubic feet: 11 bags of 1.5 cu ft, or 9 bags of 2 cu ft.

How to work it out

  1. Soil depth: 12 in bed − 1 in below the rim = 11 in
  2. 4 ft × 4 ft × 11 in ÷ 12 = 14.7 cu ft (bed volume)
  3. 14.7 cu ft + 10% for settling = 16.1 cu ft
  4. 16.1 cu ft ÷ 1.5 cu ft per bag = 11 bags

A 4 × 4 is the classic starter bed and the standard square foot garden layout: sixteen 1 ft squares. At well under a cubic yard (27 cubic feet), bags are the practical choice unless you are building several beds at once.

Adjust for your project

ft
Inside measurement, in feet. 7 ft 6 in = 7.5
ft
Inside measurement
in
Ground to the top of the boards, measured inside. Two 2×6 boards ≈ 11 in · one 2×12 ≈ 11¼ in · three 2×6 ≈ 16½ in
in
Room for water and mulch: 1–2 in is usual. We subtract it for you. 0 = fill to the top
Same-size beds — leave at 1 for one bed
Printed on the bag · raised-bed mix is usually 1–2 cu ft
More options: Settling · Mix · Bag price …
%
10–20% for fluffy bagged mixes
Mixing your own? Pick a recipe to see how much of each to buy, in bags
$
Blank to skip
$per cu yd
From a landscape yard, sold by the half yard (0.5 m³) · blank to skip
Your shopping listBuy 11 bags (1.5 cu ft) of raised-bed mix.
Soil depth (filled)
11 in
Soil to buy
16.1 cu ft (0.6 cu yd)

For this job · affiliate link
Garden dump cart11 bags will come home in the car; a dump cart gets them from the driveway to the bed in a few trips.
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Soil for several 4×4 beds 12 in tall

Soil for several 4×4 beds 12 in tall
BedsSoil to buyBags to buy
116.1 cu ft11 bags
232.3 cu ft22 bags
348.4 cu ft33 bags
464.5 cu ft44 bags
696.8 cu ft65 bags

What to know about filling a 4×4 raised bed

Nominal 4 × 4 frames are smaller inside. A box built from 2× lumber measuring 48 in on the outside is about 45 in across on the inside, because each board is 1½ in thick. That brings an 11 in fill down to about 13 cubic feet, a couple of bags fewer. Many metal and composite kits have the same gap between the box size on the label and the soil space inside, so measure the inside.

The Square Foot Gardening method uses boxes only about 6 in deep, filled with Mel’s Mix: equal parts compost, peat moss or coir, and coarse vermiculite. The figures for that shallower fill are in the questions below. Vermiculite and peat are sold in large bags, so buy the sizes closest to your share and expect leftovers you can use in a second box or in pots.

The usual mistake at this size is buying by the photo on the bag. Raised-bed and garden soils come in 1, 1.5 and 2 cu ft bags that look alike on a pallet, and the difference between 12 and 18 bags is a second trip.

Building more than one? Two 4 × 4 beds hold the same as one 4×8 raised bed. For other small footprints, see How much soil for a 2×8 raised bed, which holds exactly the same volume, and How much soil for a 3×6 raised bed.

Different size? Use the full Raised Bed Soil Calculator.

What you’ll need

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Frequently asked questions

How much Mel’s Mix for a 4×4 square foot garden 6 inches deep?

About 8.8 cubic feet in all, filled to the top with 10% for settling: 2.93 cu ft each of compost, peat moss (or coir) and coarse vermiculite.

How much soil for a 4×4 raised bed 18 inches deep?

24.9 cubic feet filled to an inch below the rim, with 10% for settling, or 17 bags of 1.5 cu ft.

How much soil for a 4×4 bed measured 45 inches inside?

For a 12 inch tall bed filled 11 inches deep, 12.9 cubic feet net, or 14.2 cubic feet with 10% for settling: 10 bags of 1.5 cu ft.

Other common sizes

Sources