How to calculate a dumpster size
Dumpsters are sized in cubic yards, and renting the right size saves a second trip.
- Estimate the volume of debris, for example by measuring the pile.
- Compare it with the dumpster classes, which are commonly 10, 20, 30, and 40 cubic yards.
- Allow for air gaps, since debris does not pack perfectly.
- Check the weight limit, because heavy debris can exceed it.
Worked example
For a typical dumpster size with length 12 ft, width 8 ft, depth 3 ft, the volume is 288.00 cubic feet. Divide by 27 for 10.67 cubic yards. With a 10 percent allowance, plan for 11.73 cubic yards.
Dumpster Size sizes and quantities
These common sizes are calculated with the same formula as the tool above, so you can find your number quickly.
| Size | Cubic feet | Cubic yards | With 10 percent extra |
|---|---|---|---|
| 10 yard class: 12 by 8 by 3 ft | 288.00 | 10.67 | 11.73 |
| 20 yard class: 22 by 8 by 4 ft | 704.00 | 26.07 | 28.68 |
| 30 yard class: 22 by 8 by 5.5 ft | 968.00 | 35.85 | 39.44 |
| 40 yard class: 22 by 8 by 7.5 ft | 1,320.00 | 48.89 | 53.78 |
Tips
- Concrete, soil, and roofing are heavy, and often have special dumpster rules.
- Break down bulky items to use space well.
- Ask what happens when you go over the weight limit.
Common mistakes to avoid
- Choosing by pile volume without allowing for air gaps.
- Ignoring weight limits for heavy debris.
- Overfilling above the sides.
Frequently asked questions
How many cubic yards do I need for a dumpster size?
Multiply the dimensions in feet and divide by 27. The example above, length 12 ft, width 8 ft, depth 3 ft, needs 10.67 cubic yards before waste.
How much extra should I order?
Add 5 to 10 percent for waste. Add more if the ground is uneven or the material is loose.
Can I enter inches and feet together?
Yes. Each box has its own unit selector, so you can mix feet and inches.
Related calculators
Rectangle Cubic Yard CalculatorFind cubic yards for a rectangle shaped area.Dump Truck Load CalculatorA truck bed has a size and a weight limit, and both matter.Pickup Truck Load CalculatorA pickup bed often has room for 1 to 2 cubic yards by volume, but payload limits usually stop you first.Trailer Load CalculatorUtility and dump trailers carry larger loads than pickups, and the weight rating decides what you can haul.Concrete Slab CalculatorSlabs for patios, sheds, garage floors, and pads are the most common ready mix order, and the thickness matters as much as the footprint.Driveway CalculatorA driveway needs concrete or asphalt on top and compacted stone below, so plan both volumes.