Cup sizes by standard
| Standard | Volume | Note |
|---|---|---|
| US customary cup (8 US fl oz) | about 237 ml | 1 US fl oz = 29.57 ml |
| US nutrition label cup | 240 ml | Rounded value used for food labels |
| Metric cup (Australia and others) | 250 ml | |
| Korean measuring cup | 200 ml | Common in Korean recipes |
| UK fluid ounce | about 28.4 ml | Smaller than the US fluid ounce |
When a source says "oz", check which country’s ounce it means.
Measuring your own glass
- Put the empty glass on a kitchen scale and zero it.
- Fill it to the level you normally drink, not to the brim.
- The grams shown are your milliliters: 1 ml of water weighs about 1 g.
No scale? Pour a bottle of known size (say 500 ml) into the glass and count the pours.
Logging tips
- Measuring the two or three glasses you use every day is enough.
- For a tumbler, count refills finished; half a tumbler counts as half.
- A drink packed with ice holds less liquid than its size suggests.
Adding your glass to the app
Set quick-add buttons to your glasses
In Water Tracker, go to Settings > Edit quick-add buttons to change each button’s amount and drink type or add more (up to six). For example: office mug 300 ml, kitchen glass 250 ml, tumbler 500 ml.
Undo or edit
The undo button next to quick add removes your last entry, and tapping an entry lets you change its amount, type or time.
Switch between ml and fl oz
Change the Display unit in Settings between ml and fl oz (US). Data is stored in ml, so switching units never changes your log.
FAQ
I can never tell if I finished the bottle.
Use the size printed on the bottle and enter the share you drank. Logging the same way every day matters more than precision.
How many ml is "8 glasses"?
About 1.9 L in US cups, 2 L in metric cups. For where the number came from, see the 8 glasses rule.
Sources: US FDA labeling rules, 21 CFR 101.9
Water Tracker: Drink Reminder
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