Estimate topsoil in cubic yards, bags, and tons for lawn topdressing, new lawn, raised beds, garden beds, and fill spots — with a 15% settlement allowance and optional raised-bed mix split.
Inches accept fractions: 12 5/8, 12-5/8, or 12.625
| Bag size | Coverage @ depth | Bags needed |
|---|---|---|
| 0.75 cu ft | 0.75 sqft | 50 |
| 1 cu ft | 1.0 sqft | 37 |
| 1.5 cu ft | 1.5 sqft | 25 |
| 2 cu ft | 2.0 sqft | 19 |
Raised-bed mix · split into topsoil / compost / amendment
The horticultural default is 60/30/10. Tweak below — the percentages must total 100.
Depth-by-use reference · sqft per yd³
| Depth | Use case | sqft per yd³ |
|---|---|---|
| 1/4″ | Light topdressing, established lawn refresh | 1296 |
| 1/2″ | Overseeding cover, thin-layer dressing | 648 |
| 1″ | Heavy topdressing, thatch repair | 324 |
| 2″ | Thin spot patching, lawn levelling | 162 |
| 4″ | New lawn over compacted subgrade | 81 |
| 6″ | Garden bed, perennial planting depth | 54 |
| 8″ | Annual / cut-flower / shallow vegetable | 40.5 |
| 12″ | Raised bed, deep-root vegetables | 27 |
Coverage = 27 ft³ per yd³ ÷ depth in feet. A 1 cu ft bag covers 4 sqft at 3″ depth, 12 sqft at 1″, 2 sqft at 6″.
Material guide · density & when to use
| Material | Density (lb/yd³) | When to use |
|---|---|---|
| Topsoil — screened | 2200 dry / 2700 moist | Lawn topdressing, garden beds, sod prep |
| Garden soil / planting mix | 1800 dry / 2400 moist | Bagged retail mix with fertiliser, ready for planting |
| Compost (mature) | 1100 dry / 1600 moist | Amendment, raised-bed component, mulch alternative |
| Fill dirt — unscreened | 2400 dry / 3000 moist | Grade work, low-spot fill, sub-base under topsoil |
| Sandy loam | 2500 dry / 3000 moist | Drainage-critical beds, root zones for turf |
Screened vs unscreened
Screened topsoil is run through a 3/4″ or 1/2″ mesh — rocks, roots, and clumps removed. Use it where the soil is the final surface (lawns, beds, sod). Unscreened or "fill dirt" is the cheap raw stuff — for sub-grade fill under a paver patio, behind a retaining wall, or under topsoil. Mixing the two saves money when you have depth: 6″ fill underneath, 4–6″ screened topsoil on top.
FAQ
Why add 15% settlement?
Loose topsoil straight off the truck contains a lot of air. Water it, walk it, or let a raised bed sit through one season and it compacts down 10–20%. A 12″ raised bed filled to the brim in spring will sit at 9.5–10.5″ by autumn — order 15% extra so you do not have to repeat the job.
Topsoil, garden soil, or compost — what's the difference?
Topsoil is mineral soil — sand/silt/clay with some organic matter. It is the bulk material for lawns and the lower half of a bed. Garden soil is bagged retail mix: topsoil plus fertiliser plus a peat or coir component, sold ready to plant. Compost is decomposed organic matter — too rich to use alone (plants get leggy), perfect as 20–30% of a mix. The raised-bed mix split in this calculator follows the 60/30/10 horticultural default.
Bagged or bulk?
The break-even sits around 2 yd³. Under 1 yd³, bagged from a big-box store wins on the delivery fee alone. Between 1 and 2 yd³, prices land within $10–20 — pick by labour preference (a pallet of 54 × 1 cu ft bags weighs ≈1.4 tons; not a fun afternoon). Above 2 yd³, bulk delivery beats bag pricing on $/yd³ and on time.
How much topsoil do I really need?
The math is short — depth × area / 27 — but the part most calculators skip is settlement. Loose topsoil contains 15–25% air; water it, walk it, or let a bed sit one season and that air leaves. A 12″ raised bed filled to the brim in spring reads 9.5–10.5″ by autumn. The 15% default settlement allowance prevents the “I’m 2″ short” callback to the supplier.
- Depth in feet:
depth_ft = depth_in / 12 - Base volume:
base_ft³ = area_sqft × depth_ft→base_yd³ = base_ft³ / 27 - With settlement:
order_yd³ = base_yd³ × 1.15 - Bag count rounds up:
bags = ceil(order_ft³ / bag_yield)
Worked example — 4×8 raised bed at 12″
- Area:
4 × 8 = 32 sqft; depth12/12 = 1 ft - Base:
32 × 1 = 32 ft³→32 / 27 = 1.19 yd³ - +15% settlement:
1.19 × 1.15 = 1.36 yd³(≈ 36.8 ft³) - At ≈ 2200 lb/yd³ dry topsoil:
≈ 1.5 tons - In bags:
37 × 1 cu ft, or19 × 2 cu ft
That 1.36 yd³ sits at the bag-vs-bulk crossover. A pallet of ≈ 54 × 1 cu ft is ≈ 2 yd³ at ≈ 3000 lb — feasible but not fun. A bulk delivery of 1.5 yd³ runs $40–60 vs $5–9/bag retail — pencil out the math before loading the trunk seven times.
Depth-by-use reference
| Depth | Use case | sqft per 1 yd³ |
|---|---|---|
| 1/4″ | Light topdressing, lawn refresh | 1296 |
| 1″ | Heavy topdressing, thatch repair | 324 |
| 4″ | New lawn over compacted subgrade, sod prep | 81 |
| 6″ | Garden bed, perennial planting depth | 54 |
| 12″ | Raised bed, deep-root vegetables | 27 |
Screened vs unscreened
Screened topsoil runs through a 1/2″ or 3/4″ mesh — rocks, roots, clumps removed. Use it where soil is the final surface: lawns, vegetable beds, perennials, under sod. Unscreened “fill dirt” is the cheap raw stuff — grade work, low-spot fill, behind retaining walls, sub-base under topsoil. Mixing saves money on depth: 6″ fill underneath, 4–6″ screened on top, only the top pays the screening premium. A 50/50 split on a 4×8 bed at 12″ saves ≈ $30–40 vs all-screened.
Raised-bed mix — 60/30/10
Topsoil alone in a raised bed is too dense — water runs off, roots stall. The horticultural default is 60% topsoil, 30% compost, 10% amendment (perlite for drainage, vermiculite for water retention, coarse sand for clay-heavy regions). On a 4×8 × 12″ bed: 0.82 yd³ topsoil + 0.41 yd³ compost + 0.14 yd³ amendment. Compost above 40% gets leggy greens; below 15% the bed compacts hard in a season.
Common questions
Topsoil, garden soil, or compost?
Topsoil is mineral soil (sand/silt/clay plus a few percent organic) — bulk material for lawns and the lower half of a deep bed. Garden soil in bag form is topsoil plus fertiliser plus peat or coir — ready to plant. Compost is decomposed organic matter, too rich to use alone, perfect as 20–30% of a mix.
Bagged or bulk?
Break-even sits around 2 yd³. Under 1 yd³, bagged from a big-box store wins on the delivery fee alone. Between 1 and 2 yd³, prices land within $10–20 — pick by labour (a pallet of 54 bags weighs ≈ 1.4 tons). Above 2 yd³, bulk wins on $/yd³ and time. For related materials see the mulch calculator, gravel calculator, or concrete calculator.
Estimator only. Soil density varies with moisture, screening, and source pit — tons are within ±15% of a load-cell weight. Confirm with the supplier; bulk yards are loose volume that settles in the bed.
