Topsoil Calculator
Work out how much topsoil to order for a new lawn, raised bed, or grading project, in cubic yards or bags.
How this calculator works
Volume = Area × Depth. Area is your length × width in square feet; depth is entered in inches and converted to feet (divided by 12) so the units match. The result in cubic feet is divided by 27 to get cubic yards, which is how bulk mulch, gravel, and topsoil are typically sold and delivered.
For bagged material, the same cubic-foot volume is divided by the coverage of one bag — a standard mulch bag covers 2 cubic feet, a gravel bag is often 0.5 cubic feet, and topsoil bags vary (this calculator lets you set the exact bag size).
Example calculation
Project: a 20 ft × 10 ft garden bed, 3 inches of mulch depth.
- Area = 20 × 10 = 200 ft²
- Volume = 200 × (3 ÷ 12) = 50 ft³
- Cubic yards = 50 ÷ 27 ≈ 1.85 yd³
- 2 ft³ bags needed = 50 ÷ 2 = 25 bags
At around $40 per cubic yard delivered in bulk, that’s roughly $74 — usually cheaper than buying 25 individual bags once you’re covering more than a couple hundred square feet.
Buying & material guidance
Mulch depth of 2–3 inches is standard for garden beds — more than 4 inches can suffocate roots and promote fungal growth. Gravel for pathways is usually 2 inches deep over landscape fabric; driveways need 4–6 inches in multiple compacted layers. Topsoil for new lawns or beds is typically 4–6 inches.
Bulk delivery is almost always cheaper than bags once you need more than about 1 cubic yard (roughly 13–14 bags of mulch), and saves you from hauling dozens of heavy bags yourself.
This tool uses the same calculation engine as our full Mulch & Gravel Calculator, with guidance tailored to this project type.
Frequently asked questions
How much topsoil do I need for a new lawn?+
Plan for 4–6 inches of topsoil depth for a new lawn — more if the existing grade is uneven or the subsoil is poor quality. Enter your lawn's area and that depth into the calculator above for an exact cubic yard figure.
How much mulch do I need for 200 square feet?+
At a standard 3-inch depth, 200 square feet needs about 1.85 cubic yards of mulch, or roughly 25 bags if using 2-cubic-foot bags.
How deep should mulch be?+
2 to 3 inches is the standard recommendation for garden beds. Going deeper than 4 inches can suffocate plant roots and encourage fungal problems.
Is it cheaper to buy mulch or gravel in bulk or bags?+
Bulk delivery is typically cheaper once you need more than about 1 cubic yard (roughly 13-14 standard bags). For smaller areas, bagged material is often more convenient despite the slightly higher per-yard cost.
How much does a yard of mulch or gravel cost?+
Bulk mulch typically costs $30–$50 per cubic yard delivered, while bulk gravel runs $40–$70 per cubic yard depending on the type (crushed stone, pea gravel, decorative stone cost more). Bagged material works out to roughly $3–$5 per cubic foot, noticeably more per yard than bulk delivery.
How many bags of mulch are in a cubic yard?+
A cubic yard is 27 cubic feet, and a standard mulch bag covers 2 cubic feet, so it takes about 13–14 bags to equal one cubic yard. Gravel bags are often smaller (around 0.5 cubic feet), so a cubic yard of gravel can take 50+ bags — bulk delivery is almost always more practical at that volume.
How much gravel do I need for a driveway?+
A gravel driveway typically needs 4–6 inches of depth in compacted layers. For a 12 ft × 50 ft driveway (600 ft²) at 5 inches deep, that works out to roughly 9.3 cubic yards — enter your exact dimensions above for a precise figure, since driveway length and width vary a lot.
How often should mulch be replaced or topped up?+
Organic mulch (bark, wood chips) breaks down over time and is typically topped up once a year, usually in spring — you often don't need a full fresh layer, just enough to restore the standard 2–3 inch depth where it has thinned or decomposed.