Topsoil Calculator

Topsoil Volume Formula:

Volume (cu ft) = Length (ft) × Width (ft) × Depth (in) / 12

Volume (cu yd) = Volume (cu ft) / 27

What each variable means:

• Length and Width, the dimensions of your area in feet. For metric users, 1 meter = 3.28 feet.
• Depth, how thick the soil layer should be, entered in inches. Divide by 12 to convert to feet for the volume calculation.

When to use this calculator: Use it any time you need to buy topsoil for landscaping, gardening, or construction. Knowing the exact volume prevents over-buying (wasting money) or under-buying (making extra trips).

Practical example: You have a raised garden bed that is 10 ft long, 4 ft wide, and you want 6 inches of topsoil.
Volume = 10 × 4 × 6 / 12 = 20 cubic feet, which is 20 / 27 = 0.74 cubic yards.
At 1.1 tons per cubic yard, that weighs about 0.81 tons (1,630 lbs).
Bagged, that is 27 of the small 0.75 cu ft bags or 14 of the 1.5 cu ft ones.

Recommended depths:

• New lawn: 4 to 6 inches (10 to 15 cm)
• Over-seeding existing lawn: 1 to 2 inches (2.5 to 5 cm)
• Raised garden bed: 6 to 12 inches (15 to 30 cm)
• Flower beds: 3 to 4 inches (7.5 to 10 cm)
• Topdressing: 0.5 to 1 inch (1 to 2.5 cm)

Weight estimates: 1 cubic yard of bulk topsoil weighs roughly 1.0 to 1.3 tons (2,000 to 2,600 lbs, or 900 to 1,180 kg). This page uses 1.1 tons per cubic yard, the same figure as the Cubic Yards to Tons converter. Moisture is what moves that number, and it moves it a lot. Soil that has sat under a week of rain can run 20% heavier than the same pile in August.

Why the bags do not add up to the bulk weight

This catches people out. Bulk topsoil at 1.1 tons a yard works out to about 81 lbs per cubic foot, but a 0.75 cu ft bag from the garden centre weighs around 40 lbs, which is only 53 lbs per cubic foot. The bagged product is screened, partly dried and often cut with compost or peat, so it is genuinely lighter and fluffier than what comes off a truck. Do the conversion by volume, never by weight, or you will order half of what you need.

The two common bag sizes are 0.75 cu ft (about 40 lbs / 18 kg) and 1.5 cu ft (about 75 lbs / 34 kg).

Tips: Order 10% extra for settling, uneven ground and spillage. Bulk delivery beats bags on price once you are past about two cubic yards, but bags win on anything you have to carry through a house or down a side passage.