Hydration Reminder Calculator
Calculate how often you should drink water throughout the day to meet your daily hydration goal.
Enter your values and click Calculate
Most people know they should drink more water but struggle to actually do it consistently throughout the day. The problem isn't motivation — it's that drinking water requires active remembering, and without a clear schedule, hydration is easily neglected during busy work or study sessions. This calculator turns your daily water goal into a concrete drinking schedule: enter your daily ounce target, your waking hours, and your glass or bottle size, and it tells you exactly how many glasses to drink and how many minutes to wait between each drink. The result is a practical reminder interval — for example, drink one glass every 90 minutes — that you can set as a phone alarm or calendar event to build a consistent hydration habit.
How It Works
Total glasses per day = Daily goal (oz) ÷ Glass size (oz). Oz per hour = Daily goal ÷ Waking hours. Minutes between drinks = (Waking hours × 60) ÷ Total glasses. The minute interval distributes your total glasses evenly across every waking minute of the day, producing the most regular possible hydration schedule. For example, 8 glasses over 16 waking hours gives 960 waking minutes ÷ 8 = one drink every 120 minutes. If you miss a reminder, the schedule resumes at the next interval — the goal is consistency over precision. Adjusting the glass size to match your actual bottle or cup gives a more realistic count that matches how you actually drink.