Soil Calculator for Raised Beds & Gardens

Soil for raised beds, planters and garden beds: enter each bed's size and depth to get cubic feet, cubic yards or litres and m³, and the bags to buy.

Raised beds, planters and new garden beds take more soil than most people expect. A 4 × 8 ft raised bed 12 inches deep holds 32 cubic feet, which is about 22 bags of 1.5 cubic feet; in metric, a 2.4 × 1.2 m bed 300 mm deep holds 864 litres, about 18 × 50 L bags. Enter each bed's size and depth (add as many beds as you like) and this calculator gives the total in cubic feet and cubic yards or litres and m³, the bag count for each size and the approximate weight. Soil settles after watering, so 10% extra is included.

Units
Bag sizes
Area
ft
ft
in
Feet and inches work too: type 12'6 or 12.5.
t/yd³
%
Volume
1.3 yd³

35.2 ft³ · 0.997 m³

Weight
1.43 tons

2,868 lb · 1.3 tonnes

Bags
24

1.5 ft³ bag

Bags needed by size
1.5 ft³ bag24
1 ft³ bag36
0.75 ft³ bag47
50 L bag20
30 L bag34
25 L bag40
1 m³ bulk bag1
How it was worked out
  1. Area: 8 ft × 4 ft = 32 ft²; × 12 in (1 ft) deep = 32 ft³
  2. 32 ft³ ÷ 27 = 1.19 yd³
  3. Plus 10% extra = 1.3 yd³
  4. 1.3 yd³ × 1.1 tons per yd³ = 1.43 tons (2,868 lb)
  5. 35.2 ft³ ÷ 1.5 ft³ per bag = 23.47, rounded up to 24 bags
Typical weights of common materials
Materialt/m³tons/yd³lb/ft³
Concrete2.402.02150
Gravel1.601.35100
Pea gravel1.601.35100
Crushed stone / crushed rock1.601.35100
River rock1.501.2694
Landscape rock / pebbles1.501.2694
Crushed limestone1.601.35100
Decomposed granite1.501.2694
Crusher run1.601.35100
Road base1.701.43106
Crusher dust1.501.2694
Aggregate (20 mm)1.601.35100
All-in ballast1.651.39103
MOT Type 1 sub-base1.801.52112
Sand1.601.35100
Topsoil1.301.1081
Garden soil1.301.1081
Fill dirt1.401.1887
Mulch0.350.2922
Bark chippings0.300.2519
Asphalt (compacted)2.321.96145

Loose, as-delivered figures; asphalt and concrete are as laid. Moisture, stone size and source change the real weight, so use your supplier's figure when you have it. Tons are US short tons (2,000 lb).

Common use cases

  • Fill raised beds and vegetable beds
  • Large planters and containers
  • Making a new border or flower bed
  • Working out whether bags or a bulk delivery is cheaper

How to use

  1. Choose feet and inches or metres and millimetres, and the country whose bag sizes you want.
  2. Enter the length and width of the area, or switch the shape to a circle, triangle or a known area. Use Add another area for L-shapes and separate beds.
  3. Enter the depth of soil. Raised beds for vegetables are often 8 to 12 inches (200 to 300 mm) deep; enter the depth of soil you'll add.
  4. Check the density and the extra allowance. Change the density if your supplier quotes a different figure.
  5. Read the volume, weight and bag count, and add a price per ton, cubic yard, m³ or bag for a cost estimate.

FAQ

How much soil do I need for a raised bed?

Length × width × depth. A 4 × 8 ft bed 12 inches deep is 32 ft³ (1.19 cubic yards); 10 inches deep is 26.7 ft³. A 2.4 × 1.2 m bed 300 mm deep is 0.86 m³, or 864 litres.

What soil should go in a raised bed?

Most gardeners use a blend of good topsoil and compost, often sold as raised bed or vegetable mix. Pure compost shrinks a lot as it breaks down, and garden soil alone can compact.

Can I fill the bottom of a deep raised bed with something else?

Many people fill the bottom of very deep beds with logs, branches or coarse organic matter and put soil on top, which cuts the amount of soil to buy. Enter just the depth of soil you'll add.

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