Raised Bed Soil Calculator
Planning a raised bed garden? Our free raised bed soil calculator turns your bed's length, width, and soil depth into cubic feet and cubic yards of soil, tells you how many bags to buy (with a 5% settling allowance), and estimates your total cost from the bag price.
Enter your numbers
Your results
| Total soil volume | — |
| Cubic yards | — |
| Estimated cost | — |
Estimates: bag counts include a 5% allowance for settling and waste, rounded up to whole bags. Soil settles 1–2 inches in the first season — plan to top up with compost each spring.
How to use this calculator
Measure the inside length and width of your raised bed in feet — the frame thickness eats a little space, so measuring the inside is more accurate. Enter your soil depth in inches (10–12 in suits most vegetables), how many identical beds you're filling, and the bag size your garden center sells (2 cu ft is most common). Your results update instantly.
Building more than one bed, or beds of different sizes? Set the number of beds for identical ones, or run the calculator once per size and add the bag counts together. Entering a price per bag adds an estimated total cost.
How it works
The soil volume of one bed is cubic feet = length (ft) × width (ft) × depth (in) ÷ 12, converting inches to feet. Multiplying by the number of beds gives the total cubic feet, and dividing by 27 gives cubic yards, the unit bulk soil is sold in.
Bag counts include a 5% allowance so you don't run short: bags = ceil(total cu ft × 1.05 ÷ bag size), rounded up to whole bags. The cost figure is a simple estimate — bags × price per bag — before tax or delivery.
Frequently asked questions
How deep should raised bed soil be?
10 to 12 inches of soil is the sweet spot for most raised beds — enough for the roots of tomatoes, peppers, and most vegetables. Shallow-rooted crops like lettuce and herbs get by with 6 to 8 inches, while carrots and other deep-rooted crops appreciate 12 to 16 inches or more.
How many bags of soil do I need for a 4x8 raised bed?
A standard 4-foot by 8-foot bed filled 12 inches deep holds 32 cubic feet of soil. With a 5% allowance for settling and waste, that's about 17 bags of 2-cubic-foot soil, 23 bags of 1.5-cubic-foot soil, or 34 bags of 1-cubic-foot soil. Try the calculator above for your exact dimensions.
Should I fill a raised bed with topsoil or compost?
A mix works best: roughly 60% topsoil or raised-bed soil blend plus 40% compost gives structure, drainage, and nutrients. Filling a bed with straight compost can hold too much water and shrink a lot as it breaks down, while pure topsoil is often low in organic matter.
Is it cheaper to buy raised bed soil in bulk or bags?
Bulk soil from a landscape yard is usually cheaper per cubic yard, especially for two or more beds — but yards often have minimums and charge delivery fees. Bagged soil costs more per cubic foot but has no minimum and is easier to transport. Enter your bag price above to see your estimated total.
Will raised bed soil settle? Do I need to top it up?
Yes — new raised bed soil typically settles 1 to 2 inches in the first season as it compacts and organic matter breaks down. That's why this calculator adds a 5% extra allowance, and most gardeners top up beds with a few inches of compost each spring before planting.