How Many Ounces Are in a Water Bottle?

Because the bottle is a metric size. Poland Spring describes its 16.9 fl oz bottle as a 500 ml bottle, and 500 ml works out to 16.91 fl oz. The label rounds that to one decimal place.

Other brands use the same size. Dasani lists a 16.9 fl oz bottle too, and Aquafina sells its 16.9 fl oz bottles in multipacks.

The single bottles these brands list run from 8 fl oz to 1.5 liters, and Poland Spring also lists a three-liter bottle. The table above shows which brand sells which size.

Not every size is a round number. Poland Spring's 23.7 fl oz bottle holds about 701 ml, and FIJI Water lists its sizes in metric, from 330 ml up to 1.5 liters.

When two bottles look alike, compare the milliliters on the labels. The milliliters to ounces converter turns any metric size into US fluid ounces.

A 16.9 fl oz bottle is 0.132 of a US gallon, so it takes 7.6 of them to make one gallon. If you track water in cups, each of those bottles counts as 2.11 cups.

A one-liter bottle goes further. It holds 4.23 cups, and 3.8 of them fill a gallon. For the full breakdown of a gallon, see how many cups are in a gallon of water.

Look for the size on the label or on the bottom of the bottle. It may be printed in fl oz, in ml or in both.

If a reusable bottle shows no size, fill it from a measuring cup and count the cups. Each US cup is 8 fl oz, or about 237 ml.

A kitchen scale is quicker. Weigh the bottle empty and then full of water: every gram of water is about one milliliter, since a liter of water weighs 1,000 grams.