Garden & landscaping calculators
Topsoil Calculator
Calculate how much topsoil, garden soil or fill dirt you need to fill or top up an area. Estimate cubic yards, whole bags and optional weight and cost.
- Fill or top up
- Bags in cu ft or liters
- Imperial & metric
Coverage
How much area does one cubic yard of topsoil cover?
One cubic yard is 27 cubic feet. Spread evenly, the area it covers depends only on the depth.
| Depth | Area covered by 1 yd³ |
|---|---|
| 1 in (25 mm) | 324 sq ft |
| 2 in (51 mm) | 162 sq ft |
| 3 in (76 mm) | 108 sq ft |
| 4 in (102 mm) | 81 sq ft |
| 6 in (152 mm) | 54 sq ft |
Geometric coverage before any allowance or settling. These are measurement examples, not recommended depths for any plant.
Measuring
Measure the space you still need to fill
A common mistake is using the full height of a bed instead of the empty depth that remains.
Filling an empty space
Use the inside length and width and the empty depth. Leave out space already taken by gravel, drainage layers or existing soil at the bottom.
Topping up an existing area
Use only the thickness of the new layer. If you know the target and existing depths, measure both from the same reference level and let the calculator subtract them.
Worked example
How the topsoil calculation works
18 ft × 12 ft at 2 in, with an optional 5% allowance and 1 ft³ bags.
- Step 1 Plan area 18 ft × 12 ft = 216 sq ft
- Step 2 Depth to feet 2 in ÷ 12 = 0.1667 ft
- Step 3 Cubic feet 216 × 0.1667 = 36.00 ft³
- Step 4 Cubic yards 36.00 ÷ 27 = 1.333 yd³
- Step 5 Optional 5% allowance 36.00 × 1.05 = 37.80 ft³ (1.40 yd³)
- Step 6 Whole 1 ft³ bags 37.80 ÷ 1 → 38 bags 38 bags supply 38.00 ft³, 0.20 ft³ more than needed.
Shortcut formula
Cubic yards = Area (sq ft) × Depth (in) ÷ 324
Buying
Check the product as well as the quantity
- 1 Confirm the product suits the jobTopsoil, garden blends and lawn top-dressing are different products. Ask the supplier what theirs is intended for.
- 2 Check whether it is sold by volume or weightIf it is sold by weight, ask for the density so you can convert.
- 3 Confirm bag volumes or bulk minimumsBag sizes vary. Bulk suppliers may have a minimum order and sell in steps.
- 4 Ask about settlingAsk how loose delivered soil relates to the finished depth you need.
- 5 Plan the deliveryWhere can the truck tip, and how will you protect the surface and move the soil?
This calculator estimates geometric volume only. It does not assess soil quality, fertility or suitability for your plants.
Next steps
Related tools and measurement guides
Calculators
Questions
Topsoil quantity and ordering questions
How do I calculate how much topsoil I need?
Multiply length × width in feet for the area, multiply by the depth in inches and divide by 324. For an 18 ft × 12 ft area at 2 in: 18 × 12 × 2 ÷ 324 = 1.33 cubic yards before any allowance.
How do I calculate a top-up over existing soil?
Choose Top up — target minus existing. Measure the target and existing depths from the same reference, such as the top of a raised-bed wall. If the target is 8 in and there is 6 in of soil, the calculator uses 2 in. If the existing depth already meets the target, the result is zero.
How many bags of topsoil make one cubic yard?
One cubic yard is 27 cubic feet: 27 bags of 1 ft³, 18 bags of 1.5 ft³, or 13.5 bags of 2 ft³ (buy 14). Use the volume on the bag, not its weight.
Can I use bags measured in liters?
Yes. One cubic yard is about 764.6 liters, so 40 L bags need 19.11 bags per cubic yard — 20 whole bags. Choose 40 L or enter another liter size under Other size.
How much does a cubic yard of topsoil weigh?
It varies a lot with the soil mix and how wet it is, so the calculator does not assume a weight. Ask your supplier for the bulk density of their product and enter it under Estimate weight.
Should I add extra for settling?
Loose soil can settle after it is spread and watered. How much depends on the product and conditions, so the calculator does not add an automatic settling factor. If you need a particular finished depth, ask your supplier how their delivered soil relates to the finished volume, and use the optional allowance if you decide to order extra.
Can I use this for a raised bed?
Yes. Measure the inside length and width of the bed, and the empty depth still to fill. Exclude space already taken by gravel, drainage layers or existing soil.