Choosing the right liner bag for a large urban trash can is simpler than you think. The key is accurate measurement. First, grab a tape measure. You need the height (from the bottom inside to the top rim), the diameter (width across the top if it's round), or the length and width (if it's rectangular). Don't forget to note the depth if the can tapers.
With these numbers, look for bags labeled with gallon capacity (like 55-gallon) and dimensions. The bag's listed height should be taller than your can's height—this gives you extra material to fold over the rim for a secure fit. For width, a bag's flat width (when laid flat) should be wider than your can's circumference divided by two. A bag that's too small will slip in; one that's too large is wasteful and clumsy.
Consider your trash type. Heavy, wet waste? Opt for a thicker, high-density bag. Lighter recyclables? A standard-duty bag may suffice. A well-fitted bag prevents tears, contains odors, and makes removal clean. Take two minutes to measure—it saves you from mess and money wasted on the wrong size.