How it works
Cubic feet = length in feet × width in feet × (depth in inches ÷ 12). In raised-bed mode, that volume is multiplied by the number of beds of the same size. Divide cubic feet by 27 for cubic yards.
Bags = ceil(cubic feet ÷ the bag's cubic feet − 1e-9). The calculator lists common retail bag sizes 0.75, 1, 1.25, 1.5, 2 cu ft. Confirm the volume printed on the bag you buy.
Settling allowance is optional and starts empty. Enter a percentage if you want extra soil.
Worked example
A 4 × 8 ft area filled 12 in deep: 4 × 8 × (12 ÷ 12) = 32 cu ft. 32 ÷ 27 = 1.19 cu yd.
With 1.5 cu ft bags: 32 ÷ 1.5 = 21.3 → 22 bags. No settling allowance is included.
Tips and common mistakes
- Measure the inside of a raised bed, not the outside of its frame.
- Depth is usually entered in inches while length and width are in feet. Above 24 in, the calculator asks you to check the unit.
- Loose soil can settle after it is placed. This calculator does not assume an amount; enter an allowance only if your supplier gives you one.
- Bagged soil sizes differ by product. Read the cubic feet on the bag rather than the bag weight.
- Buying in bulk by weight? Convert the cubic yards with Cubic Yards to Tons. Wet soil weighs more than dry soil.
Questions about this calculator
How do I calculate how much topsoil I need?
Multiply length × width in feet by the depth in feet (inches ÷ 12) to get cubic feet. Divide by 27 for cubic yards.
Example: a 4 × 8 ft raised bed filled 12 in deep is 32 cu ft, or 1.19 cu yd. That is 22 bags of 1.5 cu ft.
How much does a yard of topsoil weigh?
Dry topsoil is typically about 1.0–1.3 US tons (2,000–2,600 lb) per cubic yard. Wet soil weighs more. This is a typical range, not a standard, so ask your supplier.
How much will 1 ton of topsoil cover?
At 1.0–1.3 tons per cubic yard, 1 ton is about 0.77–1.0 cu yd, or 21–27 cu ft. That covers roughly 83–108 sq ft at 3 inches deep, or 125–162 sq ft at 2 inches.
Sources
Values marked with a link come from the linked source, which opens in a new tab. Unit conversions and our own defaults are listed separately. Every value the site uses is in the methodology source register.
Where the numbers come from 2
- Selectable topsoil bag sizes
- 0.75, 1, 1.25, 1.5, 2 cu ft/bag
- Common retail bag sizes (Texas A&M AgriLife Extension lists 0.75, 1, 1.25 and 2 cu ft; 1.5 cu ft is a common size for bagged garden soil). Check your bag. (opens in a new tab)travis-tx.tamu.edu
- Meters per international foot
- 0.3048 m/ft
- NIST, international foot conversion (opens in a new tab)nist.gov
Unit conversions and our defaults9
- Inches per foot
- 12 in/ft
- Unit definition: one foot contains twelve inches
- Cubic feet per cubic yard
- 27 cu ft/cu yd
- Geometry: 3 × 3 × 3 feet
- Centimeters per meter
- 100 cm/m
- Metric prefix definition: centi is one hundredth
- Percent denominator
- 100 %
- Definition of percent: parts per hundred
- Topsoil calculator starting dimensions
- 4, 8, 12 ft length, ft width, in depth
- Owner worked example; editable starting measurements, not a recommended soil depth
- Topsoil calculator starting bag size
- 1.5 cu ft/bag
- Owner worked example; editable selection
- Topsoil depth unit-check threshold
- 24 in
- Owner specified unit-check warning, not a recommended depth
- Count rounding tolerance
- 1e-9 unitless
- Owner specification: ceil(x − 1e-9)
- Volume and weight display precision
- 2 decimal places
- Owner specification: display volume and tons to two decimals