About the Topsoil Calculator
Whether you are making a new lawn, filling a raised bed or levelling a patch of garden, you need to know how much soil to order. This calculator takes the length and width of the area, the depth of soil and the size of the bags, and gives the volume in cubic metres, cubic yards and cubic feet, the approximate weight and the number of bags. Type the length, the width, the depth and the bag size and the topsoil appears at once, with a few related figures underneath, and you can copy the result with one tap. The sums run in your browser, so nothing you enter is uploaded.
Updated October 2026
How to use the Topsoil Calculator
- 1Enter the length, the width, the depth and the bag size.
- 2Pick the units or options from the menus if the topsoil tool offers them.
- 3Read the topsoil in the large result box.
- 4Look at the extra rows for related figures.
- 5Press Copy result to keep the answer.
When you need the topsoil
Gardeners use it to order topsoil by the load instead of buying many small bags, which is far cheaper. Landscapers use it to estimate cost and plan how many trips a truck must make.
A new lawn needs about 10 to 15 cm of topsoil, a flower bed 15 to 30 cm, and a vegetable bed or raised bed 20 to 30 cm. Settling means that the soil level will drop a little after you fill it, so add about 10 percent.
How the topsoil is worked out
Volume = length × width × depth. Weight is about 1.3 tonnes per cubic metre of loose topsoil. Bags = volume ÷ bag volume, rounded up. An area 5 m by 4 m covered to a depth of 10 cm needs 2 cubic metres of soil, which is 2.6 cubic yards, about 70.6 cubic feet and some 2.6 tonnes. In 40 litre bags that is 50 bags.
Every answer on this page comes from that one rule, so you can check any result by hand with a calculator. The figures shown underneath, such as other units, are conversions of the same answer.
- m³, yd³ and ft³
- Weight and bags
- Feet or metres, cm or inches
Mistakes to avoid with topsoil
Weights vary a lot with moisture: wet soil can weigh half as much again as dry. Treat the weight as a guide and ask your supplier for their figure. Bulk soil is usually sold by the cubic yard or cubic metre, not by weight.
On phone and computer
On a phone, type into the boxes one after another and read the topsoil underneath; Copy result puts it on the clipboard for a message or a note. On a computer the inputs sit on the left and the answer on the right, so you can change one figure and watch the topsoil move. The topsoil calculator works the same on both. Soil is only one material for the garden. Plan stones with the Gravel Calculator, bark with the Mulch Calculator, and a slab with the Concrete Calculator.
Features
- Add 10% for settling
- Wet soil is heavier
- Bulk is cheaper than bags
- Clear messages when the topsoil inputs make no sense
- Copy the result with one tap
- Private: nothing is uploaded
Frequently asked questions
How do I calculate topsoil?
Volume = length × width × depth. Weight is about 1.3 tonnes per cubic metre of loose topsoil. Bags = volume ÷ bag volume, rounded up. An area 5 m by 4 m covered to a depth of 10 cm needs 2 cubic metres of soil, which is 2.6 cubic yards, about 70.6 cubic feet and some 2.6 tonnes. In 40 litre bags that is 50 bags.
What is the formula for topsoil?
Volume = length × width × depth. Weight is about 1.3 tonnes per cubic metre of loose topsoil. Bags = volume ÷ bag volume, rounded up. The topsoil calculator applies it exactly and rounds only the displayed answer to six significant figures.
How deep should topsoil be?
About 10 to 15 cm (4 to 6 in) for lawns and 15 to 30 cm for beds.
How many bags is a cubic metre?
25 bags of 40 litres, or 50 bags of 20 litres.
Should I add extra for settling?
Yes, around 10 percent.
Is this topsoil calculator free and private?
Yes. It is free, needs no account and runs in your browser, so the numbers you type are not uploaded or stored.