IIFYM Macro CalculatorEat what you love. Hit your macros.
Find a realistic daily calorie and macro target built around your body, lifestyle, and goals—in less than a minute.
- Built around your body and routine
- Adjusts for fat loss, maintenance, or gain
- Free, instant, and no sign-up required
Example daily plan
2,140 calories
30%
Protein
45%
Carbs
25%
Fats
Your personalized plan
Calculate your macros
Enter your details below. You can update anything and recalculate whenever your routine or goal changes.
Your plan will appear here.
Fill in the calculator and we’ll estimate the daily calories, protein, carbs, and fats that fit your goal.
This calculator provides estimates, not medical advice. Results use the Mifflin–St Jeor equation, an activity factor, a starting goal adjustment, and a protein assumption. If you are pregnant, breastfeeding, under 18, managing a medical condition, or unsure whether the target is appropriate, consult a qualified clinician or registered dietitian.
How it works
A useful target, not another diet rule.
IIFYM means “If It Fits Your Macros.” It gives you a flexible structure for eating—so individual foods do not have to be labeled good or bad.
- 01
Tell us about you
Add a few basics about your body, activity, and current goal.
- 02
Get your daily targets
See a practical calorie target with protein, carb, and fat goals.
- 03
Put the plan to work
Use your targets as a flexible guide—not a list of forbidden foods.
The method
How the IIFYM calculator works
Your targets come from four steps. Nothing is hidden—you can check the math yourself.
- Step 1
Estimate BMR
Mifflin–St Jeor
10 × weight (kg) + 6.25 × height (cm) − 5 × age, then +5 for men or −161 for women.
- Step 2
Multiply by activity
TDEE = BMR × 1.2–1.9
Sedentary 1.2, light 1.375, moderate 1.55, active 1.725, very active 1.9.
- Step 3
Apply your goal
−20% / 0 / +20%
Fat loss uses 80% of TDEE, maintenance uses 100%, and muscle gain uses 120%.
- Step 4
Split into macros
Protein → fat → carbs
Protein is set at up to 2 g per kg, fat at about 25% of calories, and carbs fill what is left.
Worked example
A 30-year-old man, 80 kg and 180 cm, moderately active: BMR is 10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 1,780 calories. Multiplied by 1.55 for moderate activity, his TDEE is about 2,759 calories.
| Goal | Calories | Protein | Fat | Carbs |
|---|---|---|---|---|
| Maintenance | 2,759 | 160 g | 77 g | 357 g |
| Fat loss (−20%) | 2,207 | 160 g | 61 g | 255 g |
FAQ
IIFYM calculator questions
What does IIFYM mean?
IIFYM stands for “If It Fits Your Macros.” It is a flexible dieting approach where you hit daily targets for calories, protein, carbs, and fat instead of following a list of allowed and banned foods.
How does an IIFYM calculator work?
It estimates your basal metabolic rate with the Mifflin–St Jeor equation, multiplies it by an activity factor to get TDEE (total daily energy expenditure), adjusts for your goal, then splits the calories into protein, fat, and carbs.
Is an IIFYM calculator the same as a TDEE or calorie calculator?
It starts the same way—TDEE is the calorie step—but goes one step further by turning that calorie target into gram targets for protein, carbs, and fat that you can log against.
How accurate are IIFYM macro targets?
Treat them as a starting estimate. Equations can be off by a few hundred calories for an individual, so track your weight trend for two to three weeks and adjust calories by about 5–10% if you are not moving toward your goal.
Does this calculator use kg or pounds?
It uses kilograms and centimeters. To convert, divide pounds by 2.205 for kg and multiply inches by 2.54 for cm.
Can I use an IIFYM calculator while pregnant or breastfeeding?
Not on its own. Pregnancy and breastfeeding change energy needs in ways these equations do not model, so set targets with a doctor or registered dietitian.
Keep learning
From a target to a routine.
Get a starting number here, then learn how to use it consistently in real meals and adjust it as your trend gives you better data.
How to track macros
Set a target, weigh portions, log easy-to-miss additions, and review your weekly trend.
Read the step-by-step guide →Understand the estimateHow IIFYM targets are calculated
See what the activity, goal, calorie, and macro assumptions mean before you adjust your plan.
Read the IIFYM explainer →Check your baselineHow to calculate maintenance calories
Estimate the intake that holds your weight steady, then test it against your real trend before cutting or bulking.
Read the maintenance guide →Set your proteinHow much protein per day
See the grams-per-kilogram ranges behind the protein target and how to split it across meals.
Read the protein guide →Keep the momentum going
Turn your targets into everyday habits.
Log meals, scan foods, and keep an eye on your daily macros with Lilbite’s simple food tracker on iOS and Android.
