Quick start
- Enter the bed, planter, or lawn patch area in square feet. For odd shapes, calculate each area first and add them together.
- Enter only the soil depth you want to add in inches. A top-off depth is different from the full height of a raised bed.
- Add extra percent for settling, uneven beds, moisture or fill differences, spreading loss, or a safer order.
Best uses
Use this guide when you need a planning number for raised beds, garden top-offs, lawn topdress, planters, or comparing bulk topsoil with bagged soil.
- Estimate soil for raised beds or garden top-offs.
- Convert square feet and inches deep into cubic yards.
- Estimate 1.5-cubic-foot and 2-cubic-foot bag counts.
- Add extra percent for settling or uneven beds.
What this calculator is solving
The Soil Calculator estimates garden soil, raised bed top-offs, topsoil, and potting soil volume. It reports bulk cubic yards, cubic feet, and common retail bag counts.
Match each input label on the calculator to the bed area in square feet, the added soil depth in inches, and the extra percent for settling or uneven spreading.
The formula in plain language
In plain language: Cubic feet = square feet x depth inches / 12 x (1 + extra percent / 100). Cubic yards = cubic feet / 27. Bag counts round up cubic feet divided by 1.5 and 2 cubic feet. The examples on the page are there so you can compare your inputs with a worked example before copying the answer.
The calculator turns inches into feet, multiplies by square feet, adds extra percent, converts cubic feet to cubic yards, then rounds up 1.5-cubic-foot and 2-cubic-foot bag counts.
How to read the answer
Read cubic yards as the bulk-order number. Read cubic feet and bag counts when you are comparing retail bags, because bag sizes and fill can vary by product.
- A 120 ft2 raised-bed top-off at 4 inches deep is 40 cubic feet before extra.
- With 10% extra, the estimate becomes 44 cubic feet.
- 44 cubic feet is about 1.63 cubic yards.
- The same example rounds up to 30 bags at 1.5 cubic feet each or 22 bags at 2 cubic feet each.
Common mistakes to avoid
The big mistake is using the full raised-bed height when the bed is already partly filled. Existing soil, compost, drainage layers, moisture, settling, and the exact bag label can all move the final buy.
- Do not enter the full raised-bed height when you only need to top off the bed.
- Do not forget that loose soil can settle after watering and spreading.
- Do not mix compost, potting mix, fill material, and topsoil assumptions without checking the actual product.
- Do not treat bag counts as exact. Retail bag volume, moisture, fill, and product mix can vary.
- Check delivery minimums, plant needs, drainage, and existing soil before using the number as a final order.
Quick Raised Bed Example
Say the area is 120 square feet and you want to add 4 inches of soil. Four inches is one-third of a foot, so the raw volume is 120 x 0.333, or 40 cubic feet.
Add 10% extra for settling and uneven spreading. That gives 44 cubic feet, which is about 1.63 cubic yards.
If you buy 2-cubic-foot bags, round 44 divided by 2 up to 22 bags. If the bags are 1.5 cubic feet, round 44 divided by 1.5 up to 30 bags.
Raised Beds, Topsoil, And Potting Soil
The volume math is the same for topsoil, garden soil, and potting soil, but the product choice is not. A vegetable bed, planter, lawn low spot, and deep raised bed may need different mixes.
If the bed is partly full, use only the missing depth. If you are building layers, calculate each layer separately instead of pretending one soil number covers compost, fill, drainage, and planting mix.
Bags Versus Bulk Delivery
Cubic yards are usually easier for bulk topsoil delivery. Cubic feet are easier when you are standing in front of bag labels.
Before buying, compare the calculator result with the exact bag volume, delivery minimum, return policy, moisture level, and how much extra you can store or use elsewhere.
Research and references
These references back up the volume math, competitor intent, cubic-yard conversion, and helpful-content review behind the calculator.
Worked examples for Soil Calculator
44 ft3, 1.63 yd3, and 22 two-ft3 bags
25.2 ft3, 0.93 yd3, and 13 two-ft3 bags
25 ft3, 0.93 yd3, and 13 two-ft3 bags
35.2 ft3, 1.3 yd3, and 18 two-ft3 bags
FAQ in plain language
When should I use the Soil Calculator?
Use it when your task matches one of these common needs: Estimate soil for raised beds or garden top-offs. Convert square feet and inches deep into cubic yards. It works best when you already know the measurements, amounts, units, or options the page asks for.
What is the Soil Calculator doing with my inputs?
In plain language: Cubic feet = square feet x depth inches / 12 x (1 + extra percent / 100). Cubic yards = cubic feet / 27. Bag counts round up cubic feet divided by 1.5 and 2 cubic feet. The examples on the page are there so you can compare your inputs with a worked example before copying the answer.
What do the main Soil Calculator inputs mean?
Bed area: the final square footage of the garden bed, raised bed, planter, or lawn patch. Add separate shapes together before entering the number. Soil depth: the added soil depth in inches, not the full bed height if part of the bed is already filled. Extra percent: extra soil for settling, uneven beds, spreading loss, moisture differences, and a small ordering cushion.
How should I read the Soil Calculator answer?
Read the headline estimate first, then check the material, waste, coverage, and unit lines. For project tools, the supporting lines are often the difference between a rough idea and a list you can actually shop from.
What should I double-check before trusting the answer?
Soil settles and bag fill varies. Existing bed depth, compost or potting mix, moisture, raised-bed shape, drainage, plant needs, delivery minimums, and product labels can change the amount to buy. Also check the unit, scale, mode, and result limit because small input changes can change the answer.
How do I calculate how much soil I need?
Measure the area in square feet, choose the added soil depth in inches, then multiply square feet by depth divided by 12. Add any extra percent for settling, then divide cubic feet by 27 for cubic yards.
How much soil do I need for a raised bed?
Enter the raised bed square footage and only the depth you still need to fill. A bed that is already partly filled should use the top-off depth, not the full bed height.
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Keep exploring
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Privacy and copying results
Recent answers stay visible only while you work in the current browser tab. They are not sent to a server.
Use Copy answer when you want to save the inputs and result in notes, homework, a message, or a project list. Check the units, labels, and limits before copying.