Enter your daily water target and your bottle size. You get the exact number of bottles and how many full bottles to drink.
This calculator converts a target into bottles — it does not decide what your target should be. Don't know yours? Calculate your daily water intake first.
Bottle sizes: 500 ml / 16.9 fl oz, 20 fl oz, 24 fl oz, 32 fl oz, 40 fl oz, 1 L, or a custom size in ml, L or fl oz.
One US gallon is 128 fl oz (3.79 L). With standard 16.9 fl oz (500 ml) bottles that is about 7.6 bottles — so 8 full bottles to reach a gallon.
| Bottle size | Bottles per gallon | Full bottles |
|---|---|---|
| 500 ml / 16.9 fl oz | 7.57 | 8 |
| 20 fl oz | 6.4 | 7 |
| 24 fl oz | 5.33 | 6 |
| 32 fl oz | 4 | 4 |
| 40 fl oz | 3.2 | 4 |
| 1 L | 3.79 | 4 |
US gallon only (the UK imperial gallon is 4.55 L). A gallon is a conversion example, not a recommended daily amount.
| Daily target | 500 ml / 16.9 fl oz | 20 fl oz | 24 fl oz | 32 fl oz | 40 fl oz |
|---|---|---|---|---|---|
| 2 L (67.6 fl oz) | 4 | 3.4 | 2.8 | 2.1 | 1.7 |
| 64 fl oz (1.89 L) | 3.8 | 3.2 | 2.7 | 2 | 1.6 |
| 2.5 L (84.5 fl oz) | 5 | 4.2 | 3.5 | 2.6 | 2.1 |
| 80 fl oz (2.37 L) | 4.7 | 4 | 3.3 | 2.5 | 2 |
| 3 L (101.4 fl oz) | 6 | 5.1 | 4.2 | 3.2 | 2.5 |
| 100 fl oz (2.96 L) | 5.9 | 5 | 4.2 | 3.1 | 2.5 |
| 1 gallon (128 fl oz, 3.79 L) | 7.6 | 6.4 | 5.3 | 4 | 3.2 |
2 L ÷ 500 ml = 4 bottles (4 full bottles).
3 L ÷ 500 ml = 6 bottles (6 full bottles).
80 fl oz ÷ 16.9 fl oz = 4.73 bottles (5 full bottles).
128 fl oz ÷ 16.9 fl oz = 7.57 bottles (8 full bottles).
64 fl oz ÷ 16.9 fl oz = 3.79 bottles (4 full bottles).
Bottles = daily target ÷ bottle size. Both values are converted to milliliters first. One US fluid ounce is 29.57 ml. The full-bottle number rounds up so it meets or slightly exceeds your target.
There is no single number of bottles that suits everyone. Adult reference values for total water from drinks and food are about 3.7 L (men) and 2.7 L (women) in the US (National Academies), and 2.5 / 2.0 L in Europe (EFSA). Use the Water Intake Calculator, the daily water intake chart by weight, our methodology and the Beverage Hydration Index.