What this soil calculator does — and its lane
This tool is for the soil family: topsoil, garden soil, raised-bed soil mix, screened loam, black dirt, fill dirt, compost, potting mix and peat. It turns a bed’s dimensions into cubic yards, cubic feet and cubic metres, a count of soil-sized bags, and bulk weight in tons and tonnes, with raised-bed and settling smarts that a plain volume calculator skips. It is not a mulch calculator (organic ground cover sold by the bag and bale), not a gravel calculator (mineral aggregate sold by the ton), and not a concrete calculator (poured volume) — those are linked above. For pure unit math, use the cubic-yards calculator.
How much soil do I need?
The honest friction this fixes: most people measure a bed in feet and inches, then have to juggle the divide-by-27 step, a bag size that differs from mulch, and the fact that soil settles. Get the volume first, in cubic feet, then convert.
cubic feet = lengthft × widthft × (depthin ÷ 12)
cubic yards = cubic feet ÷ 27 · cubic metres = cubic feet × 0.0283168
bags = cubic feet ÷ bag size (round up) · coverageft² = 324 ÷ depthin per yd³
A bed of 100 ft² filled 6″ deep is 50 ft³, about 1.85 cubic yards. The single most common mistake is dividing by 3 (that is linear) or by 9 (that is area) instead of 27 for volume — this calculator does the conversion for you and shows yards, feet, bags and tons together.
Topsoil, dirt and fill dirt by the cubic yard
Topsoil, top soil, garden dirt and fill dirt are all priced and delivered by the cubic yard once you pass a couple of yards, and by the bag below that. The difference that matters for ordering is weight, because some suppliers quote by the ton: a cubic yard of loose topsoil is roughly 1.0–1.35 tons, fill dirt a little heavier at about 1.25 tons, while airy compost and potting mix are far lighter. Pick the soil type below and a representative density loads, which you can edit to a supplier’s figure.
| Soil type | Typical density (tons/yd³) | Common use |
|---|---|---|
| Topsoil | 1.10 | General beds, lawns, grading |
| Garden / screened soil | 1.10 | Planting beds |
| Raised-bed soil mix | 0.80 | Raised beds, large planters |
| Screened loam | 1.20 | Lawns, fine grading |
| Black dirt | 1.15 | Beds, top-dressing |
| Fill dirt | 1.25 | Backfill, leveling, grading |
| Compost | 0.50 | Amendment, raised-bed blend |
| Potting / container mix | 0.40 | Pots, containers |
| Peat | 0.30 | Soilless amendment |
Typical published bulk densities; wet or compacted soil is heavier — confirm with your supplier and edit the density field.
Raised bed soil — and why beds need topping off
Use the Raised bed(s) mode for a garden bed or planter. Measure the inside length and width (the outside frame overstates the soil space), set the fill depth, and if you are filling several identical beds just raise the quantity; for mixed sizes, add another bed and the totals sum across all of them. Two extras matter here. First, you can choose to leave a gap below the rim — an inch or two stops soil washing over when you water — by entering the rim height and a smaller fill height. Second, fresh soil mix is full of air and settles 10–20% in the first season as it is watered in and organic matter breaks down, so a settling top-off allowance (15% is a safe middle) is added on top so the bed starts full and stays full. A common raised-bed mix is roughly ⅓ compost, ⅓ topsoil and ⅓ an aeration material; that is guidance, not a forced calculation.
Round beds, rings and irregular shapes
The Round / ring mode uses π × radius² × depth for a circular bed or planter, and for a ring or border bed it subtracts the inner circle from the outer. The Irregular mode lets you add several sub-areas — an L-shaped bed, a curved end, beds of different sizes — and sums them into one total.
Top-dressing and fill / grading
Top-dressing is a thin layer (about ¼–½″) of compost or soil spread over a lawn or bed; the mode keeps the depth small so the volume stays realistic. Fill / grading covers leveling and backfill with an average depth, and adds a compaction allowance (about 10–25%) because loose fill dirt loses volume once it is tamped down. For grading or structural fill close to a building, treat the result as an estimate only and verify the plan with local code or a professional.
Bags or bulk: which is cheaper?
Below roughly two cubic yards (about 54 ft³), bagged soil is usually the practical choice and many suppliers will not deliver bulk in small amounts. Past that, loose soil by the cubic yard is almost always cheaper per cubic foot. This calculator shows the bag count (at a soil-bag size you choose — 0.75, 1, 1.5 or 2 ft³, smaller than mulch bags) right next to the cubic-yard figure, and lets you enter an optional price by the yard, the ton or the bag so you can compare on your own numbers.
Soil weight: cubic yards to tons
To convert soil volume to weight, multiply cubic yards by the density in tons per cubic yard. The 1.85 cubic yards of topsoil from earlier, at 1.1 tons/yd³, is about 2.0 tons (or roughly 1.85 tonnes). Because moisture and compaction swing soil weight widely, the density here is editable; for a pure volume-to-tons conversion across any material, the cubic-yards calculator has a dedicated converter.