Trash Can Sizes: Gallons to Dimensions
Enter the can capacity in gallons or litres and one dimension to get the other inside dimensions of a round or rectangular trash can.
This trash can sizes calculator works out the inside size a trash can needs to hold a given capacity, entered in US gallons or litres. You can choose a round or rectangular can, then solve for the height or the diameter to get exact inside measurements. It runs free in your browser with no sign-up, and nothing you enter is uploaded.
Use it when you are buying a can, checking a label, or deciding whether a bin will fit a space. Preset chips cover common sizes such as 13 gallon, 30 gallon and 32 gallon, and a chart shows 4 to 55 gallons in litres and cubic feet. The result is the inside size of an ideal straight-sided can, so check your real can before buying liners or lids.
How to use the Trash can size calculator
- Enter the Can capacity as a number, then pick gal or L.
- Choose the Shape of the can: Round or Rectangular.
- For a round can, choose Work out: Height, from the diameter, or Diameter, from the height. This option is only available for round cans.
- Enter the inside measurement you know: Inside diameter, or Inside width and Inside depth, or Inside height, depending on the shape and what you are solving for.
- Read the result panel. It shows the Inside diameter or Inside footprint, the Inside height, the Shape (height as a multiple of the diameter for round cans), and the Capacity in other units (US gal, litres, cubic feet).
- Scroll to the two tables for the same capacity at diameters from 10 to 22 in, and the 4 to 55 gallon chart.
To start faster, click a preset chip. The chips load 13 gal with a 12 in round can, 30 gal with an 18 in round can, 32 gal with an 18 × 15 in rectangular footprint, and 50 L with a 30 cm round can. Use Copy result to copy the result lines with a link, Copy link to save every input in the address so you can return to the same setup, or Print / save result to print or save the result.
How big is a 13 gallon trash can?
A 13 gallon trash can holds 13 US gallons, which is 3,003 cubic inches, since 1 US gallon equals exactly 231 cubic inches. For a round can, the volume formula is volume = π × diameter² × height ÷ 4. Rearranged to solve for height, it becomes height = 4 × volume ÷ (π × diameter²).
With a 12 inch inside diameter, the inside height is 4 × 3,003 ÷ (π × 144), which gives 26.55 in (67.44 cm). If the can is only 24 inches tall instead, the calculator solves for the diameter and gives 12.62 in (32.06 cm).
How many liters is a 13 gallon trash can?
A 13 gallon trash can holds 49.21 litres. One US gallon is 3.785411784 litres, so 13 × 3.785411784 = 49.21 L. The same capacity is 1.738 cubic feet.
Rectangular cans use a different formula, volume = width × depth × height. The calculator rearranges this to height = volume ÷ (width × depth). A 32 gallon can with an 18 × 15 in footprint has volume 32 × 231 = 7,392 cubic inches, so its inside height is 7,392 ÷ 270 = 27.38 in (69.54 cm).
The calculator does not guess. It takes the capacity, converts it to cubic inches, and solves for the one unknown dimension. That is why the same 13 gallons can be a tall, narrow can or a short, wide one: the table of diameters from 10 to 22 inches shows how the inside height changes as the diameter grows, and the volume stays the same. Real cans taper and have walls and rims, so treat the result as a starting size.
To size the bag for a can, you work from the can’s dimensions to the bag’s flat width and length, which the Trash bag size chart does. This page goes the other way, from capacity to dimensions.
Sources
Checked October 2026:
- Wikipedia, Gallon: 1 US gallon = 231 cubic inches = 3.785411784 litres
- Wikipedia, Drum (container): the 200-litre / 55-gallon drum and its dimensions
Worked examples
| Input | Result |
|---|---|
| 13 gal | 12 in (30.48 cm) × 26.55 in (67.44 cm) |
| 30 gal | 18 in (45.72 cm) × 27.23 in (69.17 cm) |
| 50 L | 11.81 in (30 cm) × 27.85 in (70.74 cm) |
| 32 gal | 18 in (45.72 cm) × 15 in (38.1 cm) × 27.38 in (69.54 cm) |
| 13 gal | 12.62 in (32.06 cm) × 24 in (60.96 cm) |
Calculated by the tool above with these values.
Frequently asked questions
What are the dimensions of a 30 gallon trash can?
A 30 gallon round can with an 18 inch inside diameter needs an inside height of about 27.2 in (about 69 cm). Makers vary in taper, wall thickness and fill-line placement, so the outside and printed sizes of a real can may differ from this.
How many gallons is a 55 gallon drum in litres?
A 55 US gallon drum holds 208.2 litres. The 200-litre drum is also called the 55-gallon drum in the United States, but the two figures are not identical: 200 litres is about 52.8 US gallons, so a 55 US gallon drum is a slightly larger nominal size.
How do I find the size of my trash can?
Measure the inside, from the base to the rim. For a round can, measure the inside diameter across the top. For a rectangular can, measure the inside width and depth. Enter these in the calculator and compare the result with the capacity on the label.
Why does my trash can hold a different amount than the calculator shows?
The calculator gives the inside size of an ideal straight-sided can. Real cans taper, have wall thickness and a rim, and makers draw the fill line differently. Measure your can before buying liners or a lid.
Can the calculator handle very tall or very flat cans?
It can, but the page warns that very tall or very flat shapes give results that are harder to match to real cans. Check those results against your can before you buy.
Related tools
- Trash bag size chart: use it after sizing a can to find the bag width and length that fit it.
- Plastic weight calculator: use it to estimate how much a plastic item weighs.
- Plastic density chart: use it to compare the density of different plastics.
- Recycling symbols chart: use it to identify the recycling codes printed on plastic containers.
- Mil thickness chart: use it to compare plastic film thickness in mil.
- O-ring size chart: use it to look up standard O-ring sizes.