Topsoil & Mulch Calculator

Volume = area × depth. Cover a 200 sq ft (19 m²) bed with mulch 3 in deep and you need about 1.9 yd³ (1.4 m³) — roughly 26 bags at 2 cu ft each, which is why mulch is usually bought in bulk. Topsoil at 4 in over the same bed is about 2.5 yd³ (1.9 m³), roughly 2.5 US tons (2.3 t). The calculator converts between cubic yards, bags and tons for the material you pick.

2–3 in (50–75 mm) is the sweet spot: thick enough to suppress weeds and hold moisture, thin enough to let water and air through. Keep it clear of plant stems and tree trunks — piled mulch rots bark. Below 2 in (50 mm) weeds push through and the soil dries; much beyond 4 in (100 mm) starts suffocating roots.

About 4 in (100 mm) for a new lawn (6 in / 150 mm for poor ground), 8–12 in (200–300 mm) for planting beds, and 1–2 in (25–50 mm) as a top dressing over existing soil. Buy screened topsoil — the money saved on unscreened loads goes straight back into picking out stones and weeds.

A cubic yard is 27 cubic feet, so about 14 bags of 2 cu ft mulch or 27 bags of 1 cu ft topsoil. Bags win for small jobs and clean access; anything over about half a yard is cheaper loose or in bulk bags — and a standard pickup bed holds only about 1 cubic yard (0.7 m³) struck level.

Screened topsoil runs about 1 US ton per cubic yard (1.2 t/m³) dry and noticeably more when wet; compost about 0.5–0.6 US tons/yd³ (0.6–0.7 t/m³) and bark mulch only about 0.25 (0.3). Weight matters for delivery access and for what a trailer or pickup can legally carry — a full yard of wet soil overloads most single-axle trailers.