This topsoil calculator converts an area and a depth into soil: cubic yards for bulk delivery, cubic feet, and the number of bags if you are hauling it from the garden center instead.
Soil settles and compacts roughly 15–20% after watering-in — for a finished depth that must be exact, order about 20% extra (bulk yards are cheap; a second delivery is not).
The Only Formula Soil Ever Needs
Volume = length × width × depth, depth converted to feet (inches ÷ 12); 27 cubic feet make a cubic yard. Bagged soil is sold by the cubic foot (1, 1.5 or 2 ft³ bags), bulk by the yard — this calculator speaks both dialects, and its sister tool, our Mulch Calculator, runs the identical math for the layer that goes on top. Part of our Construction Calculators collection.
Worked Example (Verified)
10 × 10 ft bed at 3 inches deep:
- Volume: 100 sq ft × 0.25 ft = 25 cubic feet
- Bulk: 25 ÷ 27 = 0.93 cubic yards — order 1 yard (the minimum delivery usually is 1 anyway)
- Bags: 25 ÷ 1.5 = 17 bags — the moment bulk delivery starts looking very wise (a yard of topsoil weighs roughly a ton; your car’s suspension has opinions)
How Deep, and Other Judgment Calls
- New lawn: 4–6″ of topsoil over scarified subsoil. Topdressing an existing lawn: ¼–½″ only — the calculator scales down happily.
- Raised vegetable beds: 8–12″ of soil (often a topsoil/compost blend; pure bagged “garden soil” counts the same by volume).
- Filling holes and low spots: measure the average depth honestly — dips lie. Slightly over-order: soil settles 15–20%.
- Bulk vs bags crossover: past ~15–20 bags (≈ 1 yd³), delivery almost always wins on price and your back.
Related Tools
- Mulch Calculator — same math, top layer
- Construction Calculators — the full collection
Frequently Asked Questions
How much topsoil do I need for 100 square feet?
At 3 inches deep: 25 cubic feet = 0.93 cubic yards, or 17 bags of 1.5 cu ft. At 6 inches, double it: about 1.85 yards.
How many bags of topsoil are in a cubic yard?
27 cubic feet per yard ÷ bag size: eighteen 1.5 ft³ bags, or 27 one-foot bags, or about fourteen 2 ft³ bags. The calculator does your exact size.
How much does a cubic yard of topsoil weigh?
Roughly 2,000–2,700 lb (about a ton to a ton and a third) depending on moisture and composition — which is why bulk soil arrives in a dump truck, not a hatchback.
How deep should topsoil be for grass?
4–6 inches under new sod or seed for roots to establish; a thin ¼–½ inch for topdressing an existing lawn. Below 3″, new lawns struggle in poor subsoil.
Should I order extra for settling?
Yes — soil compacts roughly 15–20% once spread and watered. If the finished level matters (against edging, patios, paths), add ~20% to the calculated volume.
Is this topsoil calculator free?
Yes — free, instant, no sign-up.