Garbage Bag Size Calculator — Find the Right Liner for Your Can
Enter your trash can's dimensions to find the right garbage bag gallon size and liner dimensions. Works for round (cylindrical) and rectangular cans.
Can shape
in
in
Typical liner: 24" wide × 27" long (flat)
10.3 gal
Can volume- 1
Radius (in)
11 ÷ 2 = 5.5 - 2
Base area (in²)
π × 5.5² = 95.03 - 3
Can volume (in³)
95.03 × 25 = 2,375.8 - 4
Can volume (gal)
2,375.8 ÷ 231 = 10.28231 cubic inches = 1 US gallon. Matches the "Can volume" stat.
How does this calculator work?
For a round can: volume (gal) = π(D/2)²H ÷ 231; min flat width = πD/2 + 2 in. For a rectangular can: volume = W×D×H ÷ 231; min flat width = (W+D) + 2 in. Pick the smallest standard liner size (13, 30, 33, 55 gal…) whose gallon rating and flat width both exceed your can's minimums by ~5%.
Formula
How this is calculated
A garbage bag liner has two key measurements: the flat width (half the bag's circumference when laid flat and folded) and the length (depth of the bag). For a round can, the bag must fit around the circular rim: the minimum flat width equals half the can's circumference (π × diameter / 2), plus a couple of inches of slack so the bag opens without catching. For a rectangular can, the flat width needs to equal the sum of one width and one depth (half the perimeter), again plus slack.
The bag length must be long enough to hang about 3–4 inches over the rim, so you can tie it off, plus a margin based on the can height. An extra 5–10% overhang is also common. The calculator uses the formula: min length = can height + 3 in + max(4, 7% of height).
Once the minimum flat width and can volume (in US gallons: cubic inches ÷ 231) are calculated, the calculator looks up the smallest standard liner size (4, 8, 13, 20, 30, 33, 39, 55, 65 or 95 gallon) whose rated volume and flat width both meet the minimums with a 5% volume margin. Standard dimensions shown are typical US retail liner sizes — actual bags vary slightly by brand.
Frequently asked questions
For a round can: measure the inside diameter across the opening. For a rectangular can: measure the inside width and depth. Then measure the inside height from the bottom to the rim. Use the inside dimensions so the bag fits inside — outside measurements will give a bag that is too large.
A garbage bag, when laid flat and folded in half, has a width equal to half the bag's total circumference. When you open the bag, this flat width determines how large a rim it can fit around. You need the bag's flat width to be at least half the can's perimeter.
Yes — always choose a bag rated at least 5–10% larger than the calculated can volume. Garbage is not uniformly packed, and compressible waste may bulk up above the rim before the bag is full. Larger bags also hang deeper into the can and stay put better during use.
Also known as
TG we-Calculate Editorial Team. (2026). Garbage Bag Size Calculator — Find the Right Liner for Your Can [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/garbage-bag-size-calculator
TG we-Calculate Editorial Team. "Garbage Bag Size Calculator — Find the Right Liner for Your Can." TG we-Calculate. 2026. https://we-calculate.com/calculator/garbage-bag-size-calculator.
TG we-Calculate Editorial Team, "Garbage Bag Size Calculator — Find the Right Liner for Your Can," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/garbage-bag-size-calculator
@misc{wecalculate_garbage_bag_size_calculator, title = {Garbage Bag Size Calculator — Find the Right Liner for Your Can}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/garbage-bag-size-calculator}}, year = {2026}, note = {TG we-Calculate} }
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