Garbage Bag Size Calculator

How to Use This Calculator

The calculator requires three pieces of information: your trash can's shape, its dimensions, and your preferred overhang length.

• Can shape: Select from circular, square, or rectangular. Each shape uses different measurement points—diameter for circles, uniform width for squares, and both length and width for rectangles.
• Overhang: This is the extra bag material that drapes over the rim, typically 3 to 6 inches (8–15 cm). A proper overhang prevents the bag from slipping into the can during disposal.
• Can dimensions: Measure height from the bottom to the rim. For squares, measure one side. For rectangles, measure the longer and shorter sides. For circles, measure straight across the top.

Once you enter these values, the tool computes the width and height your garbage bag should be to fit snugly without excess material.

Real-World Example

Consider a circular trash can with a 22-inch diameter and 30-inch height. If you want a 4-inch overhang:

• Bag width = (22 × π) ÷ 2 ≈ 35 inches
• Bag height = 30 + 4 + (22 ÷ 2) = 45 inches

You would need a 35 × 45 inch garbage bag. This provides enough circumference to wrap around the can's opening and sufficient length to cover the height with room to spare at the top.

Garbage Bag Sizing Formulas

The calculations vary by can shape. For rectangular and square cans, the width combines the can's dimensions, whilst the height accounts for depth and overhang. For circular cans, the width is derived from the circumference.

• Bag Width — The width of the garbage bag, measured in inches or centimetres
• Bag Height — The height of the garbage bag, measured in inches or centimetres
• Length — The longer dimension of a rectangular trash can
• Width — The shorter dimension of a rectangular or square trash can
• Diameter — The distance across a circular trash can's opening
• Height — The vertical distance from the can's base to its rim
• Overhang — The length of bag material that folds over the can's edge, typically 3–6 inches

Standard Garbage Bag Sizes

Bags are commercially produced in fixed dimensions. Matching your calculated size to the nearest standard option saves money and reduces waste.

• Small (kitchen & office): 9×12, 13×16, 16×18, 17×20, 19×25 inches
• Medium (general household): 20×22, 22×20, 24×22, 24×24, 26×36, 28×40, 30×38, 35×47 inches
• Large (renovation & commercial): 36×50, 40×46, 40×50, 42×48, 43×48, 50×48, 50×60, 61×68 inches

When your calculated dimensions fall between sizes, choose the next size up to ensure adequate coverage. Bags that are too small will tear under stress; bags that are marginally larger still contain waste effectively without significant cost penalty.

Key Considerations When Choosing Garbage Bags

Bag sizing is only part of the equation—material thickness, can placement, and load type all affect performance.

1. Account for Material Thickness — Everyday kitchen bags typically range from 0.5 to 0.9 mil (thousandths of an inch). Heavy-duty bags for renovation debris run 2.0 to 3.0 mil. Thicker bags provide puncture resistance but cost more. Match the mil rating to your waste type to avoid premature tears.
2. Measure Your Can Accurately — Use a rigid measuring tape, not a soft one, to avoid sag. Measure the interior dimensions if possible—exterior measurements may be misleading if the can has thick walls. For circular cans, measure diameter at the rim opening, not at the widest point of the body.
3. Allow Adequate Overhang — An overhang shorter than 3 inches may slip during waste placement. Longer than 6 inches creates excess material that's wasteful and awkward to tie. The 4-inch default suits most household cans, but adjust based on your can's rim smoothness and how aggressively you load waste.
4. Test Before Bulk Buying — Purchase a single box of your calculated size and test fit before ordering cases. Slight variations in can shape or bag elasticity between manufacturers can affect how snugly a bag sits. A test run costs little but prevents wasting money on poorly fitting bulk stock.