Quick answer
Soil Calculator: what it calculates
Soil Calculator calculates soil needed from area, depth and waste percent. The core method is Cubic feet = area x depth in feet x (1 + waste percent); bags = cubic feet / bag size.
Everyday Calculators
Soil Calculator
Use this soil calculator to estimate how many bags of soil, compost, or topsoil to buy for beds and garden projects.
Reviewed May 25, 2026EstimateFormula shown
ResultSoil needed
InputsArea, Depth, Waste percent, Bag size, Price per bag
FormulaSoil formula
Live calculator
Soil
Soil volume35 cu ft
1.3 cubic yards.
Bags needed24
Rounded up using 1.5 cu ft bags.
Estimated bag cost$192.00
Bags rounded up multiplied by price per bag.
Formula
Soil formula
Cubic feet = area x depth in feet x (1 + waste percent); bags = cubic feet / bag sizeDepth entered in inches is converted to feet before volume is calculated.
How to use
Steps
- Enter bed or garden area in square feet.
- Enter desired soil depth in inches.
- Add a small extra percent for settling and uneven areas.
- Enter bag size and price per bag to estimate quantity and cost.
Example
Sample calculation
Area100 sq ft
Depth4 in
With 5% extra35 cu ft
1.5 cu ft bags24 bags
Calculator use
Best for
- Quick soil needed from area, depth and waste percent.
- Quick everyday math with the result and formula in one place.
- Shopping, date, time, unit, school, or household comparisons.
- A fast check before moving the numbers into a spreadsheet.
Before relying on it
Check first
- Entering area, depth and waste percent from different time periods or scenarios.
- Mixing units, dates, or original values across the same calculation.
- Rounding early and then using the rounded number in another step.
- Copying a result without checking whether the inputs match the real-world question.
Details
What to know before using the result
These notes make the assumptions explicit, especially where the same search query can mean slightly different things.
DepthInches to feet
A 4-inch layer is one-third of a foot deep, so area and depth convert into cubic feet.
Bag roundingWhole bags
The calculator rounds up because bagged soil is sold in full bags.
SettlingMay need more
Loose soil and compost can settle after watering, mixing, and planting.
Source notes
References used for this calculator
Benchmarks
How to read the result
The calculator is a decision aid, not a fixed rule. Use the output to compare scenarios and document your assumptions.
1 - 2 inTop-dressing
A light layer for refreshing existing soil or lawns.
4 - 6 inGarden bed layer
Often used for amending or filling shallower beds.
Raised bedDeeper fill
Use the actual bed depth and consider settling after watering.
Calculator accuracy
Methodology and assumptions
The formula, inputs, example, and limitations are shown so the result is checkable, not just a number in a box.
Formula
Cubic feet = area x depth in feet x (1 + waste percent); bags = cubic feet / bag size
Inputs used
Area, Depth, Waste percent, Bag size, Price per bag
Limitations
Results are estimates for quick planning and should be checked before important financial, legal, tax, health, or business decisions.
Last reviewed
May 25, 2026
Cite this page
Toolkit Shelf. Soil Calculator. Retrieved May 25, 2026, from https://toolkitshelf.com/tools/soil-calculator
FAQ
Common questions
How do I calculate soil for a garden bed?
Multiply the bed area by soil depth in feet to get cubic feet, then divide by the bag size or by 27 for cubic yards.
How many bags of soil do I need?
Divide total cubic feet by the cubic feet in each bag and round up to a whole bag.
Should I add extra soil?
A small buffer can help with settling, uneven beds, and mixing compost or amendments.