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Bags of Soil Calculator

Updated · Standard formula, shown below

Soil volume 16.00 cu ft
Soil volume
0.59 cu yd
Result
Bags needed
11 bags
Result
Soil volume
453 L
Result

This calculator works out how many bags of soil or compost you need to fill a bed. Enter the length and width in feet, the depth in inches and the bag size in cubic feet, and you get the volume and the number of bags.

Formula

Volume (cu ft) = length (ft) × width (ft) × depth (in) ÷ 12. Bags = volume ÷ bag size, rounded up. 1 cu yd = 27 cu ft; 1 cu ft = 28.3168 L.

  • l, w: bed length and width in feet
  • d: soil depth in inches
  • bag: volume of one bag in cubic feet (a 50 L bag is about 1.77 cu ft)

Worked Example

An 8 ft × 4 ft raised bed filled 6 in deep with 1.5 cu ft bags.

  1. 8 × 4 × 6 = 192; 192 ÷ 12 = 16.00 cu ft
  2. 16 ÷ 27 = 0.59 cu yd
  3. 16 ÷ 1.5 = 10.67, rounded up to 11 bags
  4. 16 × 28.3168 = 453 L

Limits and common mistakes

  • Bagged soil settles; many gardeners add about 10-20% for settling.
  • Depth is in inches but length and width are in feet: entering 0.5 for a 6 in depth gives a result twelve times too small.
  • For round beds use the circle area (π r²) instead of length × width.
Formula used
in l | Bed length | ft | 8 | 0
in w | Bed width | ft | 4 | 0
in d | Soil depth | in | 6 | 0
in bag | Bag size | cu ft | 1.5 | 0
out cf | Soil volume | cu ft | l * w * d / 12 | 2
out cy | Soil volume | cu yd | cf / 27 | 2
out bags | Bags needed | bags | ceil(cf / bag) | 0
out lit | Soil volume | L | cf * 28.316846592 | 0

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.