Topsoil Calculator

How much topsoil do I need?

The math is area × depth: a 40 × 25 ft plot under 4 inches needs 12.3 cubic yards - about 13.5 tons, or 445 bags if you made the mistake of buying bags. That bag number is the real lesson: bulk delivery costs $25–50/yard while bagged works out to $100–150/yard-equivalent, so anything beyond a small bed patch calls for a dump truck, not a cart.

Depth by job

Topdressing a lawn: ½–1" raked in (more smothers grass). Overseeding prep: ¼–½". New garden beds: 6–12" of quality soil. New lawn from bare grade: 4–6" minimum - grass roots stop at bad subsoil, and thin topsoil is why builder-grade lawns struggle for a decade.

Ordering: yards, tons, and settling

Suppliers quote either yards or tons - screened topsoil runs ~1.1 tons/yard dry, up to 1.3 wet. It also settles roughly 15% after watering, so order 5–10% over the math and slightly crown new beds. A single-axle dump truck carries 5–6 yards; tandem 10–14.

Topsoil vs. fill dirt vs. garden soil

These aren't interchangeable, and the price gap tells you why. Fill dirt is subsoil dug from below the topsoil layer, no organic matter, and it costs noticeably less per yard than screened topsoil because it's only good for grading and leveling, never for anything you intend to grow in. Garden soil is topsoil pre-blended with compost or aged manure, usually sold bagged rather than bulk, and costs more per yard since you're paying for the amendment along with the dirt. Topsoil, what this calculator sizes, sits between the two: the organic-rich upper layer of native ground, screened to strip rocks and roots. The costly mistake is ordering fill dirt to save money on a new lawn or bed - grass and vegetables root into fill dirt about as well as they root into a gravel driveway.

Raised beds need a blend, not straight topsoil

The area × depth figure this calculator returns is total fill volume, and for a raised bed that volume isn't pure topsoil. A standard raised-bed mix runs 50–60% topsoil with the rest compost; some gardeners follow the square-foot-gardening split of one-third topsoil, one-third compost, one-third coarse material like perlite. So a 4 × 8 ft bed at 12" deep needs 1.19 cubic yards of total fill (4×8×1÷27) - at a 60/40 blend that's about 0.71 yards of topsoil and 0.47 yards of compost, ordered as two separate line items, not one yard of plain topsoil.

Irregular lots, slopes, and moving it by hand

Split odd-shaped areas at their natural boundaries and sum the pieces: a triangular corner is base × height ÷ 2 × depth, a circular bed is π × radius² × depth. On sloped ground a single depth reading understates the low end and overstates the high end, so take 3–4 spot depths across the grade and average them, or split the site into a high zone and a low zone and run each through the calculator separately. If the truck can't reach the work area, a standard 3 cubic ft wheelbarrow holds roughly 1/9 yard - a 5-yard driveway dump is about 45 loaded wheelbarrow trips to the backyard, worth knowing before you order more soil than you can physically relocate in a weekend.

Where to have it dumped

A tandem truck carrying 10 to 14 yards is heavy, and getting it onto your property is its own planning problem, separate from the volume math above.

• Check clearance first. Most delivery trucks need about 10 to 12 feet of width and enough overhead room to clear low branches, power lines, and gate frames. A driver who cannot see a safe path will dump at the curb instead, and then you are moving the whole load by hand anyway.
• Know your driveway's limits. A loaded tandem truck can weigh over 25 tons. Older concrete, asphalt over a thin base, or anything already cracked can fail under that load. When in doubt, have the driver dump on the street or a gravel pad, not a driveway you are not sure about.
• Protect what is underneath. A tarp or sheet of plywood under the dump pile keeps topsoil from mixing into grass or gravel, and makes the last few inches of cleanup far faster.
• Plan the move if the truck cannot reach the bed. A standard wheelbarrow holds about 3 cubic feet, so a 12 cubic yard order is roughly 108 wheelbarrow trips. That is a full weekend of labor for one person, and worth pricing a second pair of hands against.

Testing before you plant food in it

This calculator sizes volume, not safety, and that matters most for vegetable beds. If the topsoil is going under food crops, especially on an older property or an urban lot, it is worth knowing what is already in the ground before you add more on top.

A basic soil test through your local extension office typically runs $15 to $30 and takes two to three weeks to come back. It checks pH and nutrients, and a lead or heavy metal screen can usually be added for a modest extra fee. This matters most near older homes with lead paint history, along busy roads, or on former industrial lots. A new-build lawn on undisturbed grade rarely needs it. Test the native soil before you till new topsoil into it, since mixing does not remove contamination, it just spreads it through a larger volume.

Related tools

Finishing the yard? The sod calculator and grass seed calculator pick up where soil ends, and mulch tops the beds. Hardscape base needs the gravel calculator instead. Landscapers: price the load-in via the job costing calculator.