Raised Bed Soil Calculator: How Much Soil, and Bulk or Bags?
Enter several raised beds and their depths. Get the soil volume, a topsoil, compost and aeration split, the bags needed, and a bulk versus bag cost comparison from your prices. Runs in your browser.
The amounts are worked out in this browser. Nothing is uploaded or sent to a server. Prices are only the numbers you type.
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Nothing is sent until you press Send. Your measurements are included only if you tick the box, and you can see the full report below first.
When to use this
- You are filling one or more raised garden beds and want the total soil volume.
- You want to know how much topsoil, compost and aeration material to buy for a mix.
- You want to compare buying bags with a bulk delivery using the prices near you.
How to use
- Type one bed per line as length, width and depth. Use the units shown.
- Check the settling percentage and the mix split, which must add up to 100.
- Type your bag size, and optionally a bag price, a bulk price, a delivery fee and the step bulk is sold in.
- Press Work out the soil. Copy the list or download the table.
Examples
- An 8 x 4 ft bed, 12 in deep: 8 x 4 x 1 ft is 32 ft³. With 10 percent for settling that is 35.2 ft³, or about 1.30 yd³. A 60/30/10 mix is 21.12 ft³ of topsoil, 10.56 ft³ of compost and 3.52 ft³ of aeration material.
- Bags versus bulk: With 1 ft³ bags that mix needs 22 + 11 + 4 = 37 bags. Bulk is ordered in steps, 1.30 yd³ rounds up to 1.5 yd³ with a 0.5 yd³ step.
Understanding the result
Each bed's volume is length times width times depth. The beds are added up and increased by the settling percentage. The total is split by the mix percentages, and each part is divided by the bag size and rounded up to whole bags. Bulk is the total rounded up to the step you enter, priced per unit plus delivery. The cost comparison uses only the prices you type.
Limitations
- The tool does not know soil prices or bag sizes where you live. Every price is a number you type.
- Sloped, round or tapered beds are not modelled. Split them into simple boxes or add some extra soil.
- Different composts and topsoils settle differently. Order a little extra if you want to top up later.
- A good mix depends on your plants and climate. Ask a local supplier if unsure.
FAQ
How do I calculate soil for a raised bed?
Multiply length by width by depth to get the volume. Convert to cubic feet or cubic yards, add a little for settling and order that much.
How many cubic feet are in a cubic yard?
There are 27 cubic feet in a cubic yard. This tool does the conversion for you.
What soil mix should I use in a raised bed?
A popular recipe is about 60 percent topsoil, 30 percent compost and 10 percent aeration material, but you can change the split. It is a rule of thumb, not a rule.
Is bulk soil cheaper than bags?
Often for larger beds, but it depends on local prices and delivery. Type your prices and the tool compares the two.
Is my data sent anywhere?
No. Everything is calculated in your browser. A share link keeps your numbers after the # sign, which is not sent to a server.
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