How the irregular area calculator works
Free form beds and yards with curves are easier to handle when you find the total area first, then multiply by an average depth.
Use this cubic yard calculator for a irregular area to get cubic yards, cubic feet, cubic meters, and a cost estimate in one step.
The calculator multiplies out the volume in cubic feet, then divides by 27, because a cubic yard is a cube that is 3 feet on each side. For this shape the formula is shown below in words and symbols.
In plain words: total area times average depth, then divide by 27 if your answer is in cubic feet. Mixed units are fine. Pick feet, inches, yards, meters, or centimeters next to each box and the tool converts them for you.
Worked example for a irregular area
Take a irregular area with total area 400 sq ft, average depth 3 in. The volume works out to 100.00 cubic feet. Divide by 27 and you get 3.70 cubic yards. With 10 percent extra for waste, order about 4.07 cubic yards.
Measuring a irregular area
Break the shape into rectangles, triangles, and circles, add up the areas, and enter the total in square feet. Or paste in an area from a property map.
Common uses for the irregular area calculator
- Curved garden beds
- Natural shaped lawn areas
- Whole yard topsoil or mulch
- Land clearing and grading estimates
Irregular Area volume at different sizes
The table scales the example above so you can see how fast volume grows. Doubling the depth doubles the volume. Doubling every length quadruples the area, and with the same depth the volume quadruples too.
| Size | Cubic feet | Cubic yards | With 10 percent extra |
|---|---|---|---|
| 200 sq ft by 3 in | 50.00 | 1.85 | 2.04 |
| 400 sq ft by 3 in | 100.00 | 3.70 | 4.07 |
| 600 sq ft by 3 in | 150.00 | 5.56 | 6.11 |
| 800 sq ft by 3 in | 200.00 | 7.41 | 8.15 |
| 1,200 sq ft by 3 in | 300.00 | 11.11 | 12.22 |
| 400 sq ft by 6 in | 200.00 | 7.41 | 8.15 |
| 800 sq ft by 6 in | 400.00 | 14.81 | 16.30 |
What the 3.70 cubic yard example weighs
Volume is only half of the story when a truck is hauling the load. The table shows planning weights for the example volume in several materials.
| Material | US tons | Pounds |
|---|---|---|
| Topsoil | 4.07 | 8,148 |
| Mulch | 1.30 | 2,593 |
| Gravel | 5.19 | 10,370 |
| Sand | 5.00 | 10,000 |
| Concrete | 7.50 | 15,000 |
| Compost | 1.85 | 3,704 |
These figures are planning estimates. Real material varies in moisture, size, and compaction, so confirm weights and order quantities with your supplier.
Frequently asked questions
How do I calculate cubic yards for a irregular area?
Find the volume in cubic feet, then divide by 27. For this shape: total area times average depth. Convert inches to feet first by dividing by 12.
How many cubic yards is the example irregular area?
Total area 400 sq ft, average depth 3 in comes to 3.70 cubic yards, or 100.00 cubic feet.
How much extra should I order?
Most people add 5 to 10 percent for waste, and 10 to 15 percent for rough ground or loose material.
Can I use metric units?
Yes. Choose meters or centimeters next to any length. The result still shows cubic yards, and the cubic meter figure sits beside it.
Why does the answer change with the material?
The volume does not change, but weight and bag counts do, because each material has a different density.