Soil Calculator
Work out how much soil a bed or planter needs — from the area and depth, in cubic yards and bags, with your own bag size.
Soil fills beds; mulch covers them. The maths is the same — area times depth — but the depth is different, and so is the bag. This calculator is the soil one: 6–12 in deep, bags or bulk.
For a raised bed with a set height, use the garden bed calculator.
Your results
Enter your measurements and press Calculate.
Quantities are rounded up to whole tiles, planks, boxes or bags, after the wastage allowance. Cost appears only when you enter a price.
Formula
All lengths are converted to a single unit before the calculation: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 ft² = 0.09290304 m², 1 yd² = 9 ft². Material quantities are rounded up — you cannot buy part of a tile, plank or bag.
How to use this calculator
- Choose the shape of the area (rectangle, circle, or a known area).
- Enter the depth — 6–12 in is normal for soil in beds.
- Enter the bag volume from the packaging.
- Add a price per bag if you want a cost estimate.
Worked example
| Bed | 10 ft × 10 ft |
|---|---|
| Area | 10 × 10 = 100 ft² |
| Volume (6 in deep) | 100 × 0.5 ft = 50 ft³ = 1.85 yd³ |
| With 10% wastage | 50 × 1.10 = 55 ft³ = 2.04 yd³ |
| Bags (40 L bags) | ⌈1.56 m³ ÷ 0.04 m³⌉ = 39 bags |
Check it by hand: every step above uses the formula in the box. If your numbers match the example inputs but the calculator gives a different answer, please report it via the contact page.
Frequently asked questions
How much soil do I need for a garden bed?
Multiply the bed area by the depth. A 10 × 10 ft bed filled 6 in deep needs 2.04 yd³ — 39 bags of 40 L. This calculator does the same maths for your bed.
How deep should soil be in a raised bed?
6–12 in (150–300 mm) for most vegetables and flowers. Root vegetables need 12 in or more. The garden bed calculator works from the bed's height directly.
Should I buy soil in bulk or in bags?
Bulk (by the cubic yard) is cheaper for large jobs — a cubic yard is about 27 bags of 2 ft³. Bags are easier for small jobs and exact amounts. This calculator gives you both the volume and the bag count.
What is the difference between soil and topsoil?
Topsoil is the upper layer of soil, usually screened and sold for levelling and filling. Soil (or garden soil) is a mix for planting. Use the topsoil calculator for levelling work.
Related calculators
Estimates only. Results are for planning. Measure twice, confirm box coverage and tile sizes on the packaging you buy, and follow the manufacturer's instructions. See the disclaimer.