Cooler capacity ratings are usually optimistic.

Yes, you should measure it yourself if you need real numbers for packing.

Manufacturers measure internal volume like a box — straight lines, no curves. But coolers have rounded corners, thick insulation walls, and sometimes odd shapes. That “50-quart” cooler might only hold 42 quarts of actual cans once you account for the ice and the fact that cans don’t nest into corners.

The easiest way: Line the empty cooler with a big trash bag. Fill it with water using a measured container (like 1-gallon jugs or a 2-quart pitcher). Count how many gallons or quarts you pour in until it’s full. That’s your real internal capacity. (Don’t soak the insulation — just fill to the normal load line.)

The second best way: Use 12-oz cans. A standard can is about 13.9 fluid ounces with the air gap, but roughly 12 cans fit per gallon. Fill the cooler with cans, count them, divide by 12 for gallons, multiply by 4 for quarts. It’s not perfectly precise, but it tells you what matters: how many beers fit.

Don’t trust the label. Trust your test.

*Trusting the label is how you end up six cans short on a