Topsoil & Raised Bed Soil Calculator

How to use the Topsoil & Raised Bed Soil Calculator

1. Select Measurement system.
2. Enter Inside area length (ft or m).
3. Enter Inside area width (ft or m).
4. Enter Soil fill depth (in or cm). Enter only the depth still needing soil, not necessarily the full bed height.
5. Enter Number of identical beds or areas. For different sizes, calculate each separately and add the volumes before buying bags.
6. Enter Extra allowance (%). Choose an allowance to suit the project and supplier; no settling percentage is assumed.
7. Enter Volume per bag (selected bag unit). Use the volume printed on the bag, not its weight.
8. Select Bag volume unit.
9. Enter Price per bag (currency) if applicable. Optional. Cost uses whole bags rounded up.
10. Enter Bulk price per cubic yard (currency/yd³) if applicable. Optional. Use the same currency as the bag price. Delivery and tax are excluded.
11. Enter Bulk density (lb/ft³) if applicable. Optional. Enter a representative supplier density in pounds per cubic foot, including when dimensions are metric.
12. Keep every value in the unit shown beside its field.
13. Select Calculate and review each result and assumption.
14. Verify important decisions with local records, labels, extension guidance, or a qualified adviser.

Formula and method

Use the inside rectangular footprint and the remaining fill depth. The same soil volume calculator works for garden topsoil, raised-bed mixes and compost layers; it calculates quantity rather than selecting a soil recipe. Changing measurement systems converts the dimensions already entered. Bag counts are pooled across identical beds and rounded up once. Cost comparison uses the rounded bag count versus exact bulk volume, before delivery, tax and supplier minimums.

Worked example

A 4 ft × 8 ft raised bed needing 12 inches of fill requires 32 ft³, about 1.185 yd³ or 906.14 L before allowance: sixteen 2 ft³ bags. Two identical beds require 64 ft³ and thirty-two 2 ft³ bags.

Garden soil, raised beds and bags

This garden soil calculator estimates rectangular fill volume. Use the remaining soil depth for topping up an existing raised bed. For different bed dimensions, calculate each separately and combine the volumes before rounding the final bag count. Bag shortcuts are examples of package volumes, not supplier recommendations.

For round or tapered containers, use the potting soil calculator. Read our raised-bed planning guide and guide to choosing finished compost for material-selection context.

Understanding the result

Treat the calculated values as a planning estimate. Compare them with your field records, product information, local conditions and operational capacity before acting.

Frequently asked questions