Topsoil calculator
Topdressing a lawn, filling a raised bed, or leveling low spots? Enter the area and how deep you want the soil, and this topsoil calculator gives you cubic yards — plus cubic feet and 40 lb bag count for small jobs.
How the topsoil calculation works
Soil is sold by volume. Area (length × width) times depth gives cubic feet; dividing by 27 converts to cubic yards, the unit bulk suppliers use. A 40 lb bag holds about 0.75 cubic feet, so 36 bags make one cubic yard.
Loose soil settles 10–20% after rain and watering, so the default 10% waste isn’t really waste — it’s the soil compacting into place.
cu yd = (L × W × depth_in ÷ 12) ÷ 27 × (1 + waste%)
Topsoil calculator FAQ
How much topsoil do I need for a 10×10 ft area, 3 inches deep?
100 sq ft × 0.25 ft = 25 cubic feet = 0.93 cubic yards, plus 10% = about 1.02 cubic yards — order 1 yard, or 37 forty-pound bags.
How deep should topsoil be for a new lawn?
3–6 inches for new lawns; 1–2 inches when topdressing an existing lawn.
How many 40 lb bags make a cubic yard?
A 40 lb bag holds about 0.75 cubic feet, and a cubic yard is 27 cubic feet — so 36 bags.
Bulk or bags — which is cheaper?
Bulk wins past about one cubic yard; bags make sense for small patches where delivery fees would dominate.
Will the soil settle?
Yes, expect 10–20% settling. The calculator’s waste allowance covers it — that’s why the default is 10%.
Topsoil vs garden soil — what’s the difference?
Topsoil is for grading and lawns; garden soil is amended with compost for planting beds.