Macro Calculator
Calculate your daily macronutrient targets based on your body stats, activity level, and fitness goal.
Results
Visualization
How It Works
The macro calculator estimates your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation and then splits your calorie target into protein, carbohydrate, and fat grams. Different fitness goals shift the macro ratios to optimize body composition outcomes.
The Formula
Variables
- BMR — Basal Metabolic Rate - calories burned at complete rest
- TDEE — Total Daily Energy Expenditure - total calories burned including activity
- weight_kg — Body weight in kilograms
- height_cm — Height in centimeters
- activity_multiplier — Ranges from 1.2 (sedentary) to 1.9 (very active)
- calories_per_gram — Protein=4, Carbs=4, Fat=9 calories per gram
Worked Example
A 30-year-old male, 70 kg, 170 cm, moderately active: BMR = 10(70) + 6.25(170) - 5(30) + 5 = 1,618 kcal. TDEE = 1,618 * 1.55 = 2,508 kcal. For fat loss (2,008 kcal): Protein = 2,008 * 0.40 / 4 = 201 g, Carbs = 2,008 * 0.30 / 4 = 151 g, Fat = 2,008 * 0.30 / 9 = 67 g.
Practical Tips
- Weigh yourself at the same time each day (morning, after bathroom) and use the weekly average for accuracy.
- Protein is the most important macro to hit consistently - it preserves muscle during fat loss and supports growth during surplus.
- Adjust calories by 100-200 kcal every 2-3 weeks if progress stalls rather than making large jumps.
- Activity level is the most commonly overestimated input - when in doubt, choose one level lower.
- Track macros for at least 2 weeks before adjusting, as water weight fluctuations can mask real progress.
Frequently Asked Questions
How accurate is the Mifflin-St Jeor equation?
It is the most validated BMR equation for the general population, accurate within about 10% for most people. However, it may underestimate for very muscular individuals and overestimate for those with higher body fat percentages.
Should I eat the same macros on rest days?
For simplicity, keeping macros consistent daily works well. Advanced athletes may benefit from carb cycling (more carbs on training days, fewer on rest days) but this is not necessary for most people.
What if I cannot hit my protein target?
Prioritize whole food sources like chicken, fish, eggs, and legumes. A whey or plant protein supplement can help fill gaps. Spreading protein across 3-5 meals improves absorption and satiety.
How do I know if my macros are working?
Track body weight weekly averages, progress photos every 2-4 weeks, and strength in the gym. If weight trends match your goal direction and energy levels are stable, your macros are on target.
Is a 500-calorie deficit safe?
A 500 kcal daily deficit produces roughly 1 pound of fat loss per week, which is widely considered a safe and sustainable rate. Larger deficits can lead to muscle loss, fatigue, and metabolic adaptation.