Trash can sizes and bag fit

Because "13 gallon" is a marketing number on both the can and the bag, and neither one is a dimension.

A trash can's stated capacity is the volume of the void inside it, rounded. A trash bag's stated capacity is the volume it will hold when filled to a level the manufacturer considers sensible, also rounded — and cut deliberately oversized so one bag fits a wide range of cans. Two products both labeled 13 gallon can therefore differ by four or five inches of circumference and six inches of height, and both labels are accurate.

The consequence is the thing everyone lives with: the bag hangs over the rim, looks untidy, and slides down the inside of the can as it fills until the trash is sitting against bare plastic. It is not your can and it is not your bag. It is that the category never agreed on a dimensional standard, and no manufacturer has an incentive to publish one. The full explanation is here, and here is what actually fits what.

Across every spec sheet we pulled for this category, three brands publish usable internal dimensions and the rest do not. That gap is the reason this hub exists. Where a manufacturer states a figure we cite it; where they do not, we say so, because "the manufacturer does not publish this" is itself useful information when you are trying to work out whether a liner will fit.

• The trash can size chart — gallons, liters, quarts, typical use and the matching bag size, in one table
• 13-gallon can dimensions — the most-searched size in the category, by can style
• What size bag fits a 13-gallon can — the fit matrix, with overhang
• Trash bag sizes explained — the ladder, and what comes after 13 gallons
• Liners versus trash bags — they are not the same thing and the difference costs money
• Bathroom can sizes — the small end, where the labeling is worst

If your can is not in any chart — and plenty are not — measure it yourself. You need three numbers and a tape.

1. Rim circumference. Run the tape around the outside of the rim where the bag folds over. This is the number that decides whether a bag stays on.
2. Internal height. Floor of the can to the underside of the rim. A bag needs this plus roughly six to eight inches to fold over properly.
3. Internal width at the base. Narrower than the rim on most cans, which is why a bag that fits the rim can still bunch at the bottom.

Bag sizing is quoted as flat width by length. As a working rule, a bag needs a flat width of a little over half the can's rim circumference to wrap without stretching, and a length equal to the internal height plus about eight inches for the fold. That arithmetic is shown rather than asserted on the bag-fit page so you can check it against your own can.

Outdoor cans follow the same logic at a bigger scale, and the stakes are higher because contractor bags cost more. Outdoor can sizes are here.

Below 13 gallons the documentation gets noticeably worse: gauge is rarely printed, dimensions almost never are, and the boxes are small enough that the cost per bag doubles. The best 8 gallon trash bags is our attempt to fix that for the size most bathroom, bedroom and office bins actually take - seven bags compared on measured width, published mil and real cost per bag.

Above 13 gallons the problem changes shape rather than going away: the same shelf label covers a tall kitchen drawstring bag and a 30-by-36-inch commercial can liner, and they fit completely different cans. The best 20 gallon trash bags separates the two families, compares seven bags on published gauge and flat size, and says which one your can actually takes.

Three additions to this hub cover the questions the charts above raise: Glad vs Hefty if you are choosing between the two big bag brands, trash can liters to gallons when the can is rated in liters and the bag in gallons, and what size bags fit a 64 or 96 gallon cart for anyone lining a wheeled cart.