A 16:8 intermittent fasting schedule divides a twenty-four-hour day into sixteen hours of fasting and an eight-hour eating window. The numbers describe a timetable. They do not specify food quantities, nutrition targets or suitability for your health.
An example 16:8 fasting timetable
If your last meal ends at 8:00 PM, adding sixteen hours brings you to noon the next day. The example eating window then runs from noon until 8:00 PM. That is one possible arrangement, not the only way to write a 16:8 schedule.
| Last meal ends | Next eating window starts | Example window ends |
|---|---|---|
| 6:00 PM | 10:00 AM next day | 6:00 PM |
| 7:00 PM | 11:00 AM next day | 7:00 PM |
| 8:00 PM | Noon next day | 8:00 PM |
Does sleep count toward the sixteen hours?
Yes, when you are not eating during sleep, those hours are part of the elapsed time. In the 8:00 PM-to-noon example, the timer runs through the night. The sixteen-hour period is not sixteen waking hours.
Why the final meal time matters
The example start time is calculated from when the previous meal finishes. If a meal ends later than planned, the calculated next-window time changes too. A log that records the actual time is more informative than one that keeps an unchanged target.
The calculator uses local clock times and shows an illustrative repeating daily schedule. Travel, time-zone changes and daylight-saving changes can make elapsed time differ from a simple clock calculation. An actual fasting timer should use elapsed time when precision matters.
Comparing 16:8 with 14:10 and 12:12
With the same 8:00 PM final meal, a 12:12 example reaches its next eating window at 8:00 AM, 14:10 reaches 10:00 AM, and 16:8 reaches noon. The difference is the amount of time assigned to each window.
Seeing the examples side by side can clarify the notation. It does not establish which one is appropriate for you. A clinician can help assess that question using your health, medications and needs.
What to record in a fasting tracker
- The time the last meal actually ended.
- The fasting duration selected for the example.
- The time eating resumed.
- Any notes that explain a difference between the plan and the recorded day.
Records can help you understand consistency. They should not be treated as a measure of personal success or a reason to ignore symptoms. If a routine causes concern, seek professional advice.
Discuss changes with a clinician. Johns Hopkins advises against fasting for under-18s, people who are pregnant or breastfeeding, people with eating-disorder histories, and people with type 1 diabetes who use insulin. This tool cannot assess medical suitability.
Try the schedule calculator
Enter a last-meal time in the fasting schedule calculator and compare 12:12, 14:10 and 16:8. For more context, read the beginner’s guide to intermittent fasting.
Health information source: Johns Hopkins Medicine’s intermittent fasting overview. This page is educational and is not personalized medical advice. Published October 13, 2026 by the Fasting+ team.