Topsoil Calculator

Topsoil depth for common jobs

The jobs differ by an order of magnitude. Top-dressing an existing lawn is a thin layer: about ¼ to ¾ inch of topsoil or compost can go on turf without smothering the crown⁹. Establishing a new lawn needs a minimum of 4 to 6 inches of good-quality topsoil, measured as a firmed or settled depth⁸. The calculator starts at 4 inches as an editable example.

Topsoil vs compost

Topsoil is the mineral growing layer; compost is organic matter mixed into it. They’re sold separately and have very different weights, so calculate each as its own area if you’re buying both. For a raised bed, where the blend matters as much as the quantity, see how to fill a raised garden bed.

Coverage and settling

Freshly spread soil settles, especially after watering, which is why Penn State specifies lawn topsoil as a firmed or settled depth and suggests rain or irrigation to firm it⁸. The FHWA table shows how large the difference can be: topsoil weighs 1,620 lb per loose cubic yard but 2,430 lb in place². The calculator doesn’t add a settling allowance; the finished depth can end up lower than the depth you spread.

Bulk vs bagged topsoil

Small jobs are easy with bags; larger ones are usually cheaper by the cubic yard with delivery, though delivery fees and minimum orders can erase the saving on a small area. Use “Estimate material cost” with your own prices to compare.

Frequently asked questions

Sources & assumptions

• Volume = area × depth. Circles use π × r²; triangles use ½ × base × height.
• 1 cubic yard = 27 cubic feet; 1 cubic foot = 28.3168 liters; 1 m³ = 1.30795 cu yd.
• Bags are rounded up to whole bags from the exact, unrounded volume.
• Weights are estimates from loose, dry unit weights in the FHWA 1988 design-manual table: gravel 1.37, sand 1.30, topsoil 0.81 tons per cu yd. Moisture and stone type change them; your supplier’s figure replaces ours. Mulch weight isn’t estimated.
• No allowance is added for compaction, settling or waste, and no order size is suggested.
• Prices are only what you enter. CalcBrite doesn’t store or estimate local prices.
• Example depths are editable starting points taken from extension guidance cited in the sections above, not recommendations for your site.
• Metric bag sizes are examples of retail sizes (40–80 L); aggregates in metric markets are often sold by weight, so use Custom with the liters printed on the bag.

Sources

1. Guide to the SI, Appendix B.8: cubic yard, cubic foot and short ton factors, NIST Special Publication 811.
2. Table 6-12, Shrink/Swell Factors for Common Materials (loose and in-situ unit weights), Federal Highway Administration, Federal Lands Highway Project Development and Design Manual, Chapter 6 (September 1988); reproduced in Ohio DOT Technical Memo GE-65, Earthwork Factors (2008) — loose weights in lb per cubic yard: gravel, dry, average gradation 2,730 (wet 3,290); sand, dry 2,590 (wet 3,230); topsoil 1,620 (in place 2,430); earth loam, damp 2,360. Table notes a ±5% variation.
3. Proper Mulching Techniques (Tree Care Basics infosheet), University of Illinois Extension; Sarah Vogel & Jenny Lee; modified March 2024 — recommended depth 2 to 4 inches; composted materials 2–3 in, coarse mulches 3–4 in; keep mulch at least 4 inches from the trunk; a 3-foot radius ring is the maximum for most trees.
4. Mulching Landscape Trees, Penn State Extension; David R. Jackson; updated April 12, 2018 — 2 to 4 inches on well-drained soils, less on poorly drained; fine or double-shredded mulch 1 to 2 inches; keep mulch away from the trunk so the root flare shows; pull back 3–5 in from young trees, 8–10 in from mature trees.
5. Planting and Mulching Trees and Shrubs (fact sheet), University of New Hampshire Extension; Cathy Neal — two to three inches deep, out to the drip line; pull the mulch back a few inches from the trunk; “volcano mulching” can kill the plant.
6. Gravel Pathways in the Garden, University of California Master Gardeners, Contra Costa County; Earlene Millier; August 4, 2011, reissued March 2, 2020 — two inches is a practical minimum depth; allow four inches if thick stones or pavers are incorporated; river-run gravel never packs down, angular gravel packs to a nearly solid surface.
7. 10-Step Guide to Installing Pavers, hosted by Oregon State University Extension Service (2011 document) — excavation depth = base (4 to 6 inches) + sand bedding (1 inch) + paver thickness; base of crushed rock such as ¾-minus, compacted in layers (retail or trade listing).
8. Lawn Establishment, Penn State Extension; updated September 19, 2025 — a minimum of 4 to 6 inches (firmed or settled depth) of good-quality topsoil for good turf; till at least 4 inches.
9. Improving a Struggling Lawn and Repairing Damage, University of Maryland Extension; updated March 16, 2026 — about ¼ to ¾ inch of topsoil or compost can usually be put on turf without smothering the crown.
10. Timberline 2 cu. ft. Pine Bark Mini Nuggets Bagged Mulch, The Home Depot (retail listing) — example of the 2 cu ft bag size used as the default (retail or trade listing).
11. Rindenmulch grob 0-40 mm, 60 l, Hornbach (retail listing, Germany) — example of a 60 L metric bag (retail or trade listing).
12. Decorative garden bark, 1 × 80 litre bag, B&Q (retail listing, UK) — example of an 80 L metric bag (retail or trade listing).

Last reviewed:

October 2026

Last updated:

October 11, 2026

Calculator version:

1.0