OMAD calculator
Enter when you finished your meal. The calculator shows your 23-hour fast and when your next one-hour eating window opens.
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How an OMAD schedule works
OMAD stands for one meal a day. Timed as a schedule, that is a fast of about 23 hours and an eating window of about 1 hour, so the meal falls at the same time each day.
The fast is counted from when the meal ends. Finish at 7:00 PM and the next window opens at 6:00 PM the following day and closes at 7:00 PM. If your meal takes longer than an hour, the 20:4 calculator may describe your day better.
Questions
Is OMAD a 24-hour fast?
Not quite. If the meal is at the same time each day and takes about an hour, the gap between meals is about 23 hours. That is the pattern this calculator uses.
Can I move my meal to a different time of day?
Yes. Enter the new time as your last meal and the schedule follows from there. In the tracker you can change your plan's start time at any point, and fasts you have already recorded are kept.
What happens when the clocks change?
A fast is measured in real hours. On the night the clocks go back, a 16-hour fast that starts at 8:00 PM ends at 11:00 AM by the clock, not at noon. The calculator and the tracker both count real hours, and the calculator marks any fast that has a clock change inside it.
Is this medical advice?
No. The calculator does arithmetic on times. It knows nothing about your health and cannot tell you whether fasting, or a fast of this length, is suitable for you. Talk to a healthcare professional before you start, and read the safety information.