Garden Soil Calculator
Figure out exactly how much soil you need for raised beds, planters, or garden borders. Add every area you’re filling, and get a total volume, bag count, and cost before you shop.
Total: 100%
Best time to fill a new bed
Early spring, a few weeks before your last frost date, is the sweet spot — it gives soil time to settle before planting. Filling in fall works too, and lets the soil “rest” over winter, which many gardeners prefer for beds going into vegetables.
Measuring an odd-shaped bed
Don’t worry about being exact to the inch. Round an irregular bed to the nearest simple rectangle or circle that roughly contains it — slightly overestimating is safer than running short mid-fill.
Test before you commit
If this is a new growing space, a simple soil test (many local extension offices offer these cheaply) tells you your native soil’s pH and nutrients — useful before deciding your topsoil-to-compost ratio.
Expect it to settle
Fresh soil typically settles 10–15% within the first few weeks as it’s watered in. Many gardeners fill just short of the top, then top off once after the first good watering rather than overfilling upfront.
Seasonal reminder
Raised beds and containers lose organic matter every growing season. A light annual top-up of compost each spring keeps soil productive without a full refill.
Your Soil Estimate
Your Soil Mix Breakdown
Why Area Times Depth Gets You Volume
Think of your bed or pot as a swimming pool you’re filling with dirt instead of water. The floor of the pool is the area, the flat length and width of the space. How deep you fill it is the depth. Multiply the two together and you get volume, the actual amount of soil it takes to fill that space to the level you want. That’s the whole calculation, no matter how many beds or pots you’re working with.
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Details Worth Getting Right
A few small choices affect how well your plants actually grow, not just how much soil you buy. Based on what you entered above, here’s what’s worth a second look:
How to Fill It
Area by Area
Frequently Asked Questions
It comes down to the floor area of the bed multiplied by how deep you want to fill it. A common 4 by 8 foot bed filled 12 inches deep needs about 32 cubic feet, which is a little over 1 cubic yard. Enter your own dimensions above for an exact number, since bed sizes and fill depths vary a lot.
Topsoil is plain mineral soil, useful as a base layer but usually too dense to plant in on its own. Compost adds nutrients and improves drainage. Potting mix is lighter and soilless, designed for containers where drainage and airflow matter more than in an open bed. Most raised beds do best with a blend of all three rather than any single one alone.
Most vegetables need at least 12 inches for roots to spread freely. Flowers and shallow-rooted plants can get by with 8 inches. Succulents, herbs, and most container plants are fine at 6 inches. If you’re just top-dressing an existing bed or border, 2 to 3 inches is usually enough.
Bulk delivery is almost always cheaper per cubic yard once you need more than about a yard of soil total, roughly enough to fill two or three standard raised beds. Below that, bagged soil is usually more convenient and avoids a delivery minimum or leftover pile you don’t need.
Not quite. Leave about an inch of space below the rim so watering doesn’t wash soil over the sides. Soil also settles over the first season, so filling to about an inch under the top usually still leaves you close to full once it compacts.
Estimates are for general planning purposes. Soil volume varies by source and settles over time, so consider rounding up, especially on bulk orders.