Health & Fitness
Fasting Window Calculator
Plan intermittent fasting windows (e.g. 16:8) and see your eating window end time.
Preparing your result…
What this calculator does
Calculates Fasting Window Calculator using the formula verified against the cited source.
What your result means
An estimate from the inputs you enter, within the scope stated below — not advice.
Formula
Eating window end = last meal start + eating window hours
The step-by-step working for your own numbers appears with the result above and in the PDF report.
Frequently asked questions
Symbols and assumptions
- Inputs
- The values entered in the fields above
- • For a repeating 24-hour schedule: eating-window duration=24−fasting hours; end time=(first-meal start hour+eating duration) mod 24. Track day offset when the result crosses midnight.
Sources and review
Reviewed 2026-10-18 · Next review 2027-04-18
- • Derived clock arithmetic, not a clinical recommendation for a fasting duration. Source discusses time-restricted eating, not validation of a particular schedule. Original wording uses last-meal start incorrectly; supplied input is first-meal hour. Require 0≤fasting≤24 and first-meal hour in [0,24); define boundary behavior at 0/24.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
Quick reference
| Scenario | Fasting hours (hours) | First meal hour (24h) (h) | Eating window closes |
|---|---|---|---|
| Worked example | 16 | 12 | 20:00 |
| Half the amounts | 8 | 6 | 22:00 |
| Double the amounts | 32 | 23 | 23:00 |
Need the full picture? Get the detailed PDF report with charts, tables, formulas and working steps.
Reviewed 2026-10-18 · Next review 2027-04-18
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