Topsoil Calculator: How Much Topsoil Do I Need?
Enter the size of the bed and how deep you want the soil. You will get the volume in cubic yards, the equivalent in common bag sizes, and an optional cost — soil is one of the few materials where bags and bulk both make sense at the same scale.
Bed measurements
Use dimensions or enter the total area if you already measured it.
Purchase quantities include a 5% allowance. Soil settles after watering, so a new bed will usually sit a little lower than the depth you ordered.
How much topsoil do I need?
Multiply the bed area by the depth you want, then convert to cubic yards. The depth is the finished, levelled layer — not the depth of the hole, and not the height of the pile before you rake it out.
Soil settles once it is watered in. If the finished level matters — against a path, a patio or a lawn edge — order the depth you want and expect to top it up rather than trying to over-order for settlement.
How deep should the soil be?
| Depth | Typical use |
|---|---|
| 2 inches | Levelling and top dressing an existing lawn |
| 4 inches | Topping up a planting bed |
| 6 inches | A new bed or a raised bed |
Raised beds are the exception: fill the whole box rather than a nominal depth, so measure the internal height and use that.
Bags or bulk?
A cubic yard is 27 cubic feet, so it is 27 of the small bags or 18 of the large ones. Bulk is cheaper per yard and arrives in one drop; bags are easier when you cannot get a truck near the bed, or when the job is small enough that a delivery fee dominates the price.
Bagged soil is also usually screened and consistent, whereas bulk topsoil varies by supplier. For a bed you are planting into, that difference can matter more than the price.
How to measure a bed
For a curved bed, take the average width rather than the widest.
Add each as its own area. Areas are summed before rounding, so splitting never changes the order.
If you are topping up, measure the gap you are filling.
Common mistakes
- Ordering the excavated depth instead of the finished depth.
- Forgetting that a raised bed needs its full internal height filled.
- Buying bags for a job where a bulk drop would be cheaper, or the reverse.
- Entering the depth in inches into a field expecting feet.
Mulching over the top?
Work out the mulch layer once the soil is in and levelled.
Open the Mulch Calculator →