That's a great and very practical question! It really depends on the specific "standard" trash can, as they come in many sizes. However, a very common size for public spaces like parks and sidewalks is a 50-gallon (about 190-liter) barrel.
So, focusing on that 50-gallon model: it's not just about raw volume. You have to consider how the litter is placed. Neatly bagged waste allows for more, while loose, bulky items like coffee cups and food containers create air pockets and fill it up much faster. Typically, such a can might hold roughly 8-10 standard-sized, well-compacted trash bags before it becomes visually full and starts to overflow.
But "overflow" often happens *before* it's physically full to the brim. Once the litter reaches the opening or piles up around the top, it's considered a public nuisance and a pest attractant. Factors like wind can blow loose litter out, and rain can make the contents heavier and cause sagging.
The key takeaway? Regular emptying is crucial. Municipalities often schedule pickups based on estimated usage to prevent overflow. If you see a bin getting full, using the next available one is the best practice to help keep our shared spaces clean.