Intermittent Fasting Macro Calculator
Estimate daily macros for your goal and organize them into satisfying meals during a time-restricted eating window such as 14:10 or 16:8.
Calculate IF Macros
Medical Disclaimer: This is for informational purposes only—not medical advice. Consult a healthcare professional.
How this is calculated
Formula: Goal-based daily calorie and macro target distributed across an eating window
The calculation estimates total daily calorie needs from your resting metabolism and activity, then adjusts the total according to your goal.
Protein, carbohydrate, and fat are calculated for the full day. Fasting changes meal timing, not the basic calories contained in each gram of a macronutrient.
You can divide the daily targets among two or three meals inside your window. The preset emphasizes protein and balanced meals to make a shorter schedule more practical.
Common time-restricted schedules
| Schedule | Eating window | Practical use |
|---|---|---|
| 12:12 | 12 hours | Gentle overnight structure |
| 14:10 | 10 hours | Room for three meals |
| 16:8 | 8 hours | Often two meals plus a snack |
| 18:6 | 6 hours | More restrictive and harder to fuel well |
Fit complete nutrition into the window
An eating window is a schedule, not permission to ignore diet quality. Each meal should make a meaningful contribution to protein, produce, fluids, and total energy.
Example 16:8 day, noon to 8 p.m.
- •12:00 p.m.: eggs or tofu, whole-grain toast, fruit, and yogurt
- •3:30 p.m.: protein smoothie with milk or soy milk, oats, and berries
- •7:00 p.m.: chicken, fish, or tempeh with rice and mixed vegetables
- •Before 8:00 p.m.: nuts or cottage cheese if needed to meet targets
- •During the fast: water; unsweetened drinks if appropriate for you
Meal anchors
- Eggs, fish, poultry, or tofu
- Greek or soy yogurt
- Beans and lentils
- Whole grains and starchy vegetables
Nutrient density
- Colorful vegetables
- Whole fruit
- Nuts and seeds
- Dairy or fortified alternatives
Hydration choices
- Water
- Sparkling water
- Unsweetened tea
- Plain coffee if well tolerated
Tips
- •Start with a wider window before trying a more restrictive schedule.
- •Plan protein across at least two substantial meals.
- •Place the eating window where it supports sleep, work, and training.
- •Stop fasting and seek advice if you experience persistent dizziness, weakness, or problematic food preoccupation.
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Frequently asked questions
Not inherently. Your daily calorie and nutrient needs remain based on your body and goal; fasting mainly changes when you consume them.
This tool provides general estimates for education and is not medical advice. Consult a doctor or registered dietitian before fasting if you take medication, have diabetes or another medical condition, are pregnant or breastfeeding, are under 18, or have a current or past eating disorder.
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