Intermittent Fasting Calculator
Intermittent Fasting Calculator
Explore a daily eating window, see your fasting and eating times on a 24-hour clock, and save a schedule that fits your routine. A practical planner — not a promise of weight loss.
← Explore all free toolsCreate your daily schedule
Choose a window you’re comfortable with. Shorter eating windows are not automatically healthier or more effective.
Choose a fasting / eating rhythmAll times use your own local clock. A window may cross midnight; the schedule will label the following day.
Your daily window
This is a recurring clock-based schedule, not a countdown you must obey. Adjust it as needed.
Your 24-hour clock
Clock positions use local time: midnight is at the top, noon at the bottom.
Example daily rhythm
The suggested meal point is optional, not a rule. You don’t need to eat at every marker.
How to use an intermittent fasting calculator
Choose your preferred fasting duration, then enter when you want to start or finish eating. The calculator works out the other end of the eating window, when the fast begins, and when your next eating window opens. For example, a 16:8 schedule with a first meal at noon has an eating window from noon to 8 PM and a fasting window from 8 PM until noon the following day.
There’s no need to force 16:8 if 12:12 or 14:10 fits your life better. Even if you use a fasting routine, the quality and adequacy of your meals still matter. For more context, read our beginner’s intermittent fasting guide and how to build healthy eating habits.
Educational schedule planner for adults. Times are based on the browser’s local clock and assume a normal repeating 24-hour day. Daylight-saving transitions may shift elapsed hours on the changeover day. This tool cannot determine whether fasting is medically appropriate for you. Personal schedules are saved only to your browser when you choose to save them.