How much soil do I need?
Type the size of your bed and how deep to fill it. The soil calculator shows how much soil to buy in cubic yards, cubic feet, cubic metres and litres, and how many bags of your size that is.
- Cubic yards
- 0.81
Soil needed: 0.81 yd³ (22 ft³); bags to buy: 15.
- Cubic feet
- 22
- Cubic metres
- 0.623
- Litres
- 623
- Bags
- 15
Cubic yards: 0.81. Soil needed: 0.81 yd³ (22 ft³); bags to buy: 15.
How to calculate
Computes the volume of soil or topsoil to fill rectangular or round garden beds to a depth, with an extra share for settling, in cubic yards, cubic feet, cubic metres and litres, and the number of bags.
Example with the default inputs (Bed shape Rectangle, Length 10 ft, Width 4 ft, Depth 6 in, Number of beds 1, Extra for settling 10%, Bag size 1.5 ft³): Soil needed: 0.81 yd³ (22 ft³); bags to buy: 15.
Method: Volume = length × width × depth (or π × diameter² ÷ 4 × depth) × beds × (1 + extra ÷ 100); bags = volume ÷ bag size, rounded up.
- The bed is filled level to the depth you type, with straight sides.
- Extra for settling is 10% by default: loose soil settles after watering, and some is spilled. Set it to 0 for the bed volume alone.
- Bags are counted by the volume printed on the bag; soil is not compressed or loosened further.
Worked examples
Each example is checked against the calculator on every build.
- Bed shape Rectangle, Length 10 ft, Width 4 ft, Depth 6 in, Number of beds 1, Extra for settling 10%, Bag size 1.5 ft³ gives Cubic feet 22, Cubic yards 0.814815, Cubic metres 0.622971, Bags 15.Source: NIST Handbook 44, Appendix C (1 yd³ = 27 ft³, 1 ft = 0.3048 m)
- Bed shape Rectangle, Length 10 ft, Width 3 ft, Depth 6 in, Number of beds 1, Extra for settling 0%, Bag size 1.5 ft³ gives Cubic feet 15, Bags 10.Source: NIST Handbook 44, Appendix C
- Bed shape Rectangle, Length 9.843 ft, Width 3.281 ft, Depth 11.81 in, Number of beds 2, Extra for settling 0%, Bag size 1.413 ft³ gives Cubic metres 1.8, Litres 1,800, Cubic yards 2.354311, Bags 45.Source: NIST Handbook 44, Appendix C (1 L = 0.001 m³, 1 yd = 0.9144 m)
- Bed shape Circle, Diameter 6 ft, Depth 12 in, Number of beds 1, Extra for settling 0%, Bag size 2 ft³ gives Cubic feet 28.274334, Bags 15.
How it works
The calculator finds the volume of one bed, multiplies it by the number of beds, and adds the extra for settling:
- Rectangular bed: length × width × depth
- Round bed: π × diameter² ÷ 4 × depth
- Soil to buy = bed volume × number of beds × (1 + extra ÷ 100)
- Bags = soil to buy ÷ bag size, rounded up to a whole bag
The results show in four units, all exact: 1 yd³ = 27 ft³ = 0.764554857984 m³; 1 ft³ = 0.028316846592 m³; 1 L = 0.001 m³. Bag sizes can be typed in cubic feet, US quarts or gallons (1 qt = ¼ gal, 1 gal = 231 in³), cubic yards, litres or cubic metres.
Exact arithmetic. Each measurement is read as the exact decimal you typed, in the unit you typed it in (12 ft 6 in is exactly 150 in). The page stores a measurement as a number in metres (or cubic metres) and reads it back as the decimal with the fewest significant digits, in one of the box's units, that gives the same stored number; a feet-and-inches pair counts by its value in inches (12 ft 6 in counts as 150, and 426.72 cm, exactly 14 ft, stays 426.72 cm), and on a tie the unit listed first in the box's unit menu wins. Every step for a rectangular bed is exact, so 15 ft³ in 1.5 ft³ bags is exactly 10 bags, not 11. A round bed uses π.
Rounding. Cubic yards and cubic feet show with at most 2 decimals, cubic metres with 3 and litres with 1, each rounded half up from its exact value, with trailing zeros left off. Bags are rounded up to a whole number. A result shown with 15 or more significant digits (a very large value with its decimals) can differ from the exact value in its last shown digit, because the page keeps results as 64-bit floating-point numbers, which hold about 16 significant digits.
Assumptions
- The bed is filled level to the depth you type, with straight sides.
- The extra for settling is 10% by default, from 0% to 100%.
- A bag holds the volume printed on it.
- Lengths are more than 0 and at most 1,000 m; the depth at most 100 m; 1 to 1,000 beds; a bag from 1 mL to 100 m³.
Worked examples by hand
A 10 × 4 ft bed, 6 in deep, 10% extra, 1.5 cu ft bags. 10 × 4 × 0.5 = 20 ft³; × 1.1 = 22 ft³, which is 22 ÷ 27 = 0.81 yd³ and 0.623 m³. 22 ÷ 1.5 = 14.67, so 15 bags.
A 10 × 3 ft bed, 6 in deep, no extra. 10 × 3 × 0.5 = 15 ft³; 15 ÷ 1.5 = 10 bags exactly.
Two 3 × 1 m beds, 30 cm deep, no extra, 40 L bags. 3 × 1 × 0.3 × 2 = 1.8 m³ = 1,800 L = 1.8 ÷ 0.764554857984 = 2.35 yd³. 1,800 ÷ 40 = 45 bags.
A round bed 6 ft across, 1 ft deep, no extra, 2 cu ft bags. π × 6² ÷ 4 × 1 = 28.27 ft³; 28.27 ÷ 2 = 14.14, so 15 bags.
Other questions people ask
How do I calculate how much soil I need?
Multiply the length by the width by the depth, all in the same unit. A bed 10 ft long and 4 ft wide filled 6 in (0.5 ft) deep needs 10 × 4 × 0.5 = 20 cubic feet. Divide by 27 for cubic yards: 0.74 yd³. Add about 10% for settling: 22 ft³, or 0.81 yd³.
How many bags of soil do I need for a raised bed?
Divide the soil volume by the volume on one bag and round up. The 22 ft³ above fills 22 ÷ 1.5 = 14.67 bags of 1.5 cu ft, so buy 15 bags. With 2 cu ft bags it is 11 bags.
How many cubic feet are in a cubic yard?
A cubic yard is 3 ft × 3 ft × 3 ft = 27 cubic feet, which is about 0.765 cubic metres or 765 litres. Bulk soil is sold by the cubic yard; bagged soil by the cubic foot, quart or litre.
How deep should soil be in a raised bed?
It depends on the plants. Many vegetables grow well in 6 to 12 in (15 to 30 cm) of soil; root crops and tomatoes do better with 12 in or more. Type the depth you plan to fill; the calculator does not pick one for you.
Why add extra soil for settling?
Loose soil from a bag or a truck settles as it is watered and packed down, and some is spilled. The calculator adds 10% by default. Set the extra to 0% to get the volume of the bed alone.
How do I calculate soil for a round bed?
Use the area of a circle: π × diameter² ÷ 4, then multiply by the depth. A round bed 6 ft across and 1 ft deep holds π × 36 ÷ 4 × 1 = 28.27 ft³ of soil.