From measured space to purchasable material
A topsoil order depends on the depth of new material, not the full depth of soil already in the garden. This calculator converts a rectangular area and added depth into placed volume, then applies an entered settlement allowance for ordering. Bag quantities use the labeled cubic-foot volume, while the bulk estimate uses cubic yards. The allowance is not a universal property of topsoil; its usefulness depends on the blend, moisture and handling. Soil suitability, contamination, fertility and drainage must be assessed separately from the quantity estimate.
Measure, select yield and round the order
- Measure the area that needs additional soil.
- Enter only the new layer depth.
- Adjust the loose-material allowance and compare bulk volume with bag count.
Net requirement and purchase calculation
A worked example
A 20 × 10 ft area with 4 in of new soil needs 66.67 ft³ placed. Adding 15% yields 76.67 ft³, about 2.84 yd³ or 77 one-cubic-foot bags.
Soil: what changes the result?
Compare the layer or product assumptions behind the material order. The comparisons below are calculated from this page’s default example. Each row changes only the named input; all other inputs stay at their displayed example values. These are mathematical scenarios, not measurements from a completed project.
| Changed assumption | Default input | Comparison input | Result: default → comparison |
|---|---|---|---|
| Area length | 20 ft | 24 ft | Target placed soil volume: 66.6667 → 80 cu ft Loose order including allowance: 76.6667 → 92 cu ft |
| Area width | 10 ft | 12 ft | Target placed soil volume: 66.6667 → 80 cu ft Loose order including allowance: 76.6667 → 92 cu ft |
| Added soil depth | 4 in | 4.8 in | Target placed soil volume: 66.6667 → 80 cu ft Loose order including allowance: 76.6667 → 92 cu ft |
| Additional loose soil allowance | 15 % | 18 % | Loose order including allowance: 76.6667 → 78.6667 cu ft Bulk cubic yards: 2.8395 → 2.9136 yd³ |
Displayed values are rounded. Whole-pack results change in steps; continuous quantities may change before a new pack is needed. To compare your actual project, enter your dimensions above, save a scenario, then change one assumption.
Coverage, allowance and purchasing limits
- Do not substitute topsoil for a potting mix without checking plant and container needs.
- A measured uneven grade may require several depth zones.
- Bagged soil sold by weight cannot be converted accurately without its volume or density.
Frequently asked questions
How much topsoil for 200 square feet at 4 inches?
The placed volume is 66.67 ft³. With the example 15% ordering allowance it becomes 76.67 ft³, or 2.84 yd³.
Does bag weight equal soil volume?
No. Moisture and material composition affect weight. Use the labeled volume whenever possible.
Should I use the existing soil depth?
Enter the depth of new material being added, not the entire soil profile.
Read the project guides
- Mulch and Topsoil: Compare Bulk Yards with Bags
Convert bed area and depth into bulk cubic yards and whole bags, then compare complete material and delivery costs without mixing weight and volume.
- How Much Soil and Compost Does a Raised Bed Need?
Measure internal raised-bed volume, subtract headspace and excluded layers, split a chosen blend into component volumes and round bag quantities accurately.
Calculation method: JICWH methodology. Examples are planning assumptions, not product recommendations.