Raised Bed Soil Calculator

Enter the size of your raised beds to see how much soil fills them, and how to split the mix.

H

Creator

Haali

Updated October 2026

Calculate your raised bed soil

Results update as you type

Units
Length
Width
Number of beds
Bed depth
Bed height
Bag size
Bag size
Price (optional)
Add 10% for settling

You need about

Area
Volume
Estimated cost

Suggested mix

Topsoil (60%)
Compost (30%)
Grit or perlite (10%)

Enter your measurements above to see how much raised bed soil to order.

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Related: Garden Soil Compost Topsoil Mulch

What soil goes in a raised bed?

Raised beds dry out faster than the ground, so they need soil that holds moisture but still drains. Plain garden soil packs down too hard. Potting compost on its own shrinks and runs out of food. A mix of topsoil, compost and something gritty works best.

A simple mix

60% screened topsoil for structure and minerals.
30% compost for food and moisture.
10% grit, perlite or fine bark to keep it open and free draining.

The calculator splits your total into these three parts so you know how much of each to buy.

How deep should a raised bed be?

Salad leaves and herbs 15 to 20 cm
Most vegetables 30 cm
Root crops like carrots and parsnips 30 to 45 cm
Beds on a hard surface 45 cm or more

How does the calculation work?

Litres = length (m) × width (m) × height (m) × 1,000

A bed 2.4 m by 1.2 m and 30 cm deep: 2.4 × 1.2 × 0.3 = 0.86 m³, or 864 litres. That is 18 bags of 50 L.

Filling tips

Fill the bottom third of a deep bed with logs, branches or upturned turf to save soil.
Fill to the top. Soil settles by about 10% in the first season.
Top up with 3 to 5 cm of compost every spring.
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