Fasting · Tool 1 of 5
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Intermittent Fasting Window Planner
Most fasting calculators tell you one thing: when your eating window opens. That is the easy part. The hard part is what happens when your only free time to train is 7 a.m. and your window does not open until noon.
Tell me about your day
Reading the plan above
The planner works backwards from the time your window opens: the length of the fast and the hours you have to eat follow from that, and your session time is flagged as inside the window, just before it, or deep in the fast. Where training lands matters more than the exact ratio. For how to handle each case, see fasting around training.
What this planner does not decide
It does not set your calories or your protein. Fasting is a schedule, not a diet — it changes when you eat, and that only produces fat loss if it also changes how much you eat over the week.
Related calculators
- TDEE CalculatorMaintenance calories and a calorie target, in kg or lb.
- Protein Intake CalculatorDaily protein by training type, from your bodyweight.
- Weight Loss Timeline CalculatorA week-by-week plan with the diet breaks already scheduled.
- One Rep Max CalculatorEstimate a 1RM and get working weights for the session.
Common questions
Does black coffee break the fast?
For the purposes of fat loss, no. Plain water, black coffee and unsweetened tea contain effectively no energy. What matters is calories.
Should I train fasted to burn more fat?
Training fasted shifts which fuel you use during the session, but total fat loss over weeks is driven by total energy balance. Choose fasted or fed based on which one lets you train harder and show up more often.
Is a longer fast better?
A longer fast is not automatically better, and it is usually harder to keep up. Pick the longest fast you can hold for three months, not the longest you can hold for three days.
Can women use the same windows as men?
Many can, but the common advice is to start at 14:10 or 16:8 rather than jumping to 18:6 or OMAD, and to shorten the fast if menstrual changes, persistent fatigue or sleep disruption appear.
Do I need to enter my weight here?
No. This planner only needs times and a session type — bodyweight does not change when the window opens or closes. The optional field switches between kilograms and pounds and exists only so you can carry the same number straight into the TDEE calculator without doing the conversion yourself.
Read next
- How to Fit a Fasting Window Around Your Training Your training hour is usually fixed, while your eating window can move. Timetables for early, lunchtime, evening, twice-a-day and shift-work trainers.
- Train Fasted or Fed? Choose by Session Type Fasted training changes the fuel mix, not the fat-loss maths. Here is which sessions it suits, which it can hurt, and how to test it for yourself.
- How to Break a Fast Without Undoing the Day Most fasting plans fall apart in the two hours after the window opens. What to put in the first meal, how big to make it, and when to ease in.