Intermittent Fasting Calculator
Plan your eating and fasting windows for 14:10, 16:8, 18:6, 20:4 or one-meal-a-day schedules. Example: a 16:8 plan with your first meal at 12:00 PM means eating until 8:00 PM and fasting until noon the next day.
Show steps
How to use the Intermittent Fasting Calculator
- Enter the values in the fields.
- Press Calculate to see the result with the steps shown.
Formula and method
Eating window length = 24 – fasting hours. Window end = first meal time + eating hours.
Intermittent fasting schedules
| Plan | Fast | Eat | Example |
|---|---|---|---|
| 14:10 | 14 h | 10 h | 8 AM to 6 PM |
| 16:8 | 16 h | 8 h | 12 PM to 8 PM |
| 18:6 | 18 h | 6 h | 12 PM to 6 PM |
| 20:4 | 20 h | 4 h | 2 PM to 6 PM |
| OMAD | 23 h | 1 h | One meal a day |
What the evidence says
Randomized trials find that intermittent fasting helps weight loss about as much as ordinary calorie restriction; it works for some people mainly because it makes eating less easier.
What breaks a fast
Calories break a fast. Water, plain tea and black coffee do not. Medicines and supplements should follow your clinician’s advice.
Cautions
This calculator gives estimates for education and planning, not medical advice. Check with your doctor before major changes to diet, exercise or medicines, especially if you have a medical condition.
Frequently asked questions
What is 16:8 intermittent fasting?
Fasting 16 hours and eating in an 8 hour window.
When does the fat-burning phase begin?
Roughly 12 or more hours into a fast, though it is gradual.
Can I drink coffee while fasting?
Black coffee is fine.
How much weight can I lose?
Similar to regular calorie restriction.
Who should not fast?
Pregnant women, people with eating disorders and some with diabetes.
Can I exercise while fasting?
Yes, if you feel well.
Sources
- Trepanowski et al., JAMA Intern Med 2017: Alternate-day fasting vs daily calorie restriction
- Harvard Health: Intermittent fasting
Related calculators
Related to This Article
More math articles
- 7th Grade Georgia Milestones Assessment System Math Worksheets: FREE & Printable
- Adding and Subtracting Matrices: Examples and Free Practice
- How to Find Absolute Values and Opposites of Rational Numbers
- BI Incubation, Implant Quarantine, and Early Release
- The Ultimate 6th Grade IAR Math Course (+FREE Worksheets)
- How Hard Is the ALEKS Math Test?
- Graphing Histograms
- Math Solver
- The Ultimate CLEP College Math Formula Cheat Sheet
- PSAT/NMSQT Math Practice Test PDF with Answers
What people say about "Intermittent Fasting Calculator: Eating Window for 16:8, 18:6 & More"?
No one replied yet.