Topsoil calculator

How to use the topsoil calculator

Estimate how much topsoil you need for a lawn, bed or top-dressing project. Enter the area, depth, bag size and waste allowance to see cubic yards, bags and estimated weight.

1. Choose Feet / inches or Metres / cm.
2. Enter Length and Width, or enter Or a known area to override them.
3. Enter the soil Depth and choose the bag volume printed on the bag.
4. Set the waste percentage, then review the topsoil volume, bags and estimated weight.

What to enter

Unit system

Choose Feet / inches for US customary measurements or Metres / cm for metric measurements.

Length

Enter the area length in feet or metres. The default is 20 feet or metres, depending on the selected unit system.

plus inches

Add a remaining length in inches or centimetres. The default is 0.

Width

Enter the area width in feet or metres. The default is 10 feet or metres.

plus inches

Add a remaining width in inches or centimetres. The default is 0.

Or a known area

Enter a known area in square feet or square metres. This overrides Length × Width when provided.

Depth (4–6 in new lawn, 2–3 in top-dressing, 6–12 in raised bed)

Enter the topsoil depth in inches or centimetres. The default is 4 inches.

Bag volume in cubic feet as printed on the bag (0.75, 1, 1.5, 2 or 3 cu ft; 1 cu ft ≈ 28.3 L)

Choose the bag size printed on the product. The default is 0.75 cu ft.

Extra material for cuts, breakage and settling, in % (0–50). Trade default 5%

Enter an allowance from 0% to 50%. The default is 5% for settling.

Example: 200 square feet at 4 inches deep

For a 20 ft × 10 ft area at 4 in deep, the area is 20 × 10 = 200 sq ft. Net volume is 200 × 4 ÷ 12 = 66.67 cu ft, using the calculator's rounded display. With 5% waste, 66.6667 × 1.05 = 70 cu ft. That equals 70 ÷ 27 = 2.59 cu yd, rounded to two decimals. Using 0.75 cu ft bags, 70 ÷ 0.75 = 93.33 bags, so the calculator rounds up to 94 bags. Estimated weight is 2.592592 × 1.1 = 2.85 tons, rounded to two decimals.

How the topsoil estimate is calculated

The calculator converts the entered dimensions to square feet and inches internally. Net volume in cubic feet = area × depth ÷ 12. The ordered volume = net volume × (1 + waste percentage ÷ 100). Cubic yards = ordered cubic feet ÷ 27. Bags = ordered cubic feet ÷ selected bag size, rounded up to a whole bag. Estimated weight = cubic yards × 1.1 US tons per cubic yard. In metric mode, the displayed volume, area, depth and weight are converted to metric units; bag sizes remain the cubic-foot sizes printed in the input.

Reading the results

Use Topsoil to order as the volume to buy. It includes the selected waste allowance and is shown in cubic yards in imperial mode or cubic metres in metric mode. The bags result is always rounded up to a whole bag. Estimated weight is shown in US tons for imperial mode or metric tonnes for metric mode.

Limitations and common mistakes

• The calculator assumes a rectangular area when using Length and Width. Use Or a known area for an irregular area that you have already measured.
• The default 5% allowance is a tool setting for settling, not a guarantee of the final grade.
• Topsoil weight is estimated at 1.1 US tons per cubic yard. Moisture can change the actual weight; the tool notes a possible variation of about ±10%.
• Waste percentage must be between 0% and 50%, and bag size must be 0.75, 1, 1.5, 2 or 3 cu ft.

Frequently asked questions