Garden Soil Calculator: How Much Soil Do You Really Need?
Estimate garden soil volume with our free calculator. Compares bulk vs bagged costs. Works for raised beds, circles, and curved gardens. No email required.
✅ Free · No signup · No email required📊 Data from public industry sources🕐 Prices updated June 2026🔒 We never see your data🧑💻 Built by EarthWise · About us
Stop Guessing – Get the Right Amount of Soil
📊 Data sourced from publicly available industry standards. See our methodology page for formulas, sources, and limitations.
Ever bought too much soil and ended up with a muddy mountain in your driveway? Or worse, not enough and had to make another trip mid-planting? I've been there.
When I moved last year, I made this exact mistake with my raised beds. The math seemed simple – length times width times depth – but I forgot about soil settling. That bagged soil compacts about 15-20% after watering. So my beds ended up looking half-empty.
This calculator fixes that. It accounts for compaction, works with circles and curves, and even compares bulk vs bagged costs. Based on real data from Home Depot and Lowe's, you'll get an estimate that actually matches what you'll need.
Soil Coverage at a Glance
Here's how much ground a single cubic foot of soil covers at different depths. Use this as a quick reference, but the calculator above gives you the exact number.
Why Most Soil Calculators Get It Wrong
Honestly, this won't work if your walls are textured – wait, that's for paint. For soil, the biggest mistake is ignoring compaction. When you fill a bed, soil settles. Water it once and it drops an inch or two. Most calculators don't account for this. Ours adds a 15% buffer automatically. You can adjust it if you want, but it's already set based on what we've found works. Another issue? Most tools only handle rectangles. What if your garden is a circle or has curved edges? Our calculator handles that. Just pick the shape that matches your bed. No more fudging the numbers.
Bagged vs Bulk Soil: Which Saves You More?
Here's the real deal. Bagged soil is convenient – you can grab it at any garden center. But it costs more per cubic foot. Bulk soil is cheaper but you need a truck and a place to dump it. The calculator above shows both side by side. For a typical 4x8 raised bed at 6 inches deep, you'll need about 16 cubic feet. That's 16 bags at $7.99 each – roughly $128. Or one cubic yard of bulk soil at $35 – plus delivery fees. For small projects, bags win. For anything over 10 cubic feet, bulk is usually cheaper. But honestly, it depends on your local prices. The calculator uses national averages but you can adjust the numbers.
How to Measure Your Garden Bed Correctly
Grab a tape measure. For rectangles, measure length and width in feet. For circles, measure the diameter. For irregular shapes, break it into smaller rectangles and add them up. Depth is critical – most vegetables need 6-12 inches. Root crops like carrots need deeper soil. Leafy greens can get by with 4-6 inches. The calculator uses a recommended depth of 6 inches as default, but you can change it. Don't forget to measure the inside of your bed, not the outside. That extra inch or two of frame thickness adds up.
Frequently Asked Questions
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Frequently Asked Questions
- How much soil do I need for a 4x8 raised bed?
- Use the calculator above. For a 4x8 bed at 6 inches deep, you'll need about 16 cubic feet, or roughly 16 bags of 1-cubic-foot soil. That's with the compaction buffer included.
- Should I buy bagged or bulk soil?
- It depends on the size of your project. For small beds under 10 cubic feet, bagged is easier. For larger projects, bulk is cheaper per cubic yard. The calculator shows both costs so you can compare.
- Does soil really settle that much?
- Yes. Expect 10-20% settling after watering. That's why our calculator adds a 15% buffer. If you skip it, your bed will look half-empty after a few weeks.
- Can I use this calculator for circular beds?
- Absolutely. Just select 'circle' from the shape options in the calculator. Enter the diameter and depth. It works for circles, rectangles, and irregular shapes.
- What depth should I use for vegetables?
- Most vegetables need 6-12 inches. Carrots and potatoes need deeper soil – at least 10 inches. Lettuce and herbs can do with 4-6 inches. The calculator defaults to 6 inches.
- How many cubic feet are in a cubic yard?
- 27 cubic feet. That's 3 feet by 3 feet by 3 feet. A typical bulk delivery is 1 cubic yard, which covers about 54 square feet at 6 inches deep.
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