Raised bed soil calculator
Estimate soil volume, compost blend, and bags for raised garden beds from length, width, fill height, and bed count.
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Tool guide
Raised bed soil calculator: how it works
Practical information to understand the result and use this tool correctly.
About Raised bed soil calculator
Enter the inside length and width of the box, the soil fill height (not the wall height if you leave a lip), and how many identical beds you are filling. Order volume is length × width × fill height × bed count × (1 + waste). Bags are that volume divided by the bag you buy, rounded up.
A planning mix splits the order into compost and the rest as topsoil or potting mix. The default is 30% compost by volume, a common vegetable-bed starting point, not a soil test. Drop compost to 0% for a straight topsoil order, or raise it when the bag blend already includes less organic matter than you want.
Metric results show cubic meters and liters per bag. Foot results show cubic feet, cubic yards (cubic feet ÷ 27), and cubic-foot bags. Leftover is purchased bag volume minus the order volume. Optional price is bags times price per bag.
Nothing is uploaded. Zero, negative, and oversized boxes are rejected. This is a planter-box soil list. Open mulch, gravel, or topsoil spread by area and depth stays in the gravel calculator; seed weight stays in the grass seed calculator.
How to use it
- 1Choose meters or feet, then enter inside length, width, and fill height.
- 2Set the number of identical beds and a waste allowance for settling or spillage.
- 3Pick a compost share and the bag size you will buy.
- 4Review total volume, compost, topsoil, bags, leftover, and optional cost, then copy the order.
Frequently asked questions
- How is raised bed soil calculated?
- Volume is inside length × inside width × fill height × number of beds × (1 + waste). Compost is that volume times the compost share. Bags are order volume divided by one bag, rounded up. Cubic yards are cubic feet divided by 27.
- Should I use wall height or fill height?
- Use the soil depth you will actually fill. Leaving 2–5 cm (about an inch) below the rim avoids spill when you water. Do not use the outside wall height if the boards sit above the soil line.
- Does this replace the gravel calculator?
- No. Gravel, mulch, and open topsoil spreads use area and a thin depth. This tool is for boxed beds: bed count, fill height, and a compost versus topsoil split.
- Does the calculation leave the browser?
- No. Dimensions, mix, prices, and the order summary stay on your device.