How many litres of soil does a raised bed hold?

Multiply length by width by depth in metres to get cubic metres, then multiply by 1000 for litres. A 2 m by 1 m bed filled 30 cm deep holds 0.6 cubic metres, which is 600 litres.

What mix should I fill a raised bed with?

A common vegetable mix is roughly 60 percent quality topsoil to 40 percent compost. The compost adds nutrients and structure while the topsoil gives body and holds moisture.

Should I overfill the bed?

Yes, slightly. Fresh soil and compost settle over the first few weeks, so filling to the brim leaves you at a good level once it beds in.

What is the Raised Bed Soil Calculator?

Calculate how much topsoil or compost a raised bed needs from its length, width and fill depth, across any number of beds. Shows cubic metres, litres and bags. Runs in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

Raised Bed Soil Calculator

Name: Raised Bed Soil Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Filling a raised bed is a straight volume calculation, but soil and compost are sold by the litre or cubic metre, so you need to convert your bed dimensions into those units. This calculator does it for one bed or many.

How it works

volume per bed = length × width × (depth in cm / 100)
total volume   = volume per bed × number of beds
litres         = total volume × 1000
bags           = ceil(litres / bag litres)

Working in litres makes it easy to compare bagged compost against a bulk delivery priced by the cubic metre.

Worked example

One 2 m × 1 m bed filled to 30 cm, using 50-litre bags:

Volume = 2 × 1 × 0.30 = 0.6 m³ = 600 litres
Bags = ceil(600 / 50) = 12 bags

What to watch

Settling. Fresh material drops over the first few weeks, so fill to the top and expect to top up a little later in the season.

Bulk is cheaper for big projects. Several beds quickly add up to a cubic metre or more, where a loose delivery usually beats the bag price. Use the cubic-metre figure to compare.