CodeKitHubWhat Is This Tool?
Macronutrients ('macros') are the three nutrient categories that provide calories: protein (4 kcal/g), carbohydrates (4 kcal/g) and fat (9 kcal/g). While a plain calorie target tells you how much to eat, a macro split tells you what to eat it as — which matters for muscle retention, satiety and training performance, not just the number on the scale.
This calculator starts from your TDEE (the same Mifflin-St Jeor-based estimate used in calorie calculators), then applies a gram split tuned to your goal: higher protein and a moderate deficit for cutting, balanced macros at maintenance, and a modest surplus with enough protein for bulking. The result is three gram targets you can track with any food-logging app.
Why Use It?
- Converts your TDEE directly into protein, carb and fat grams — not just a single calorie number.
- Three goal presets — cut, maintain, bulk — each with a sensible, evidence-informed macro split.
- Uses the same Mifflin-St Jeor formula as trusted calorie and BMR calculators for consistency.
- Supports metric (cm, kg) and imperial (feet/inches, pounds) units.
- Free and instant, with nothing uploaded — the calculation runs entirely in your browser.
How to Use
- Select your sex, enter your age, height and weight.
- Choose your activity level and your goal — cut, maintain or bulk.
- Press calculate to see your daily calories, plus protein, carbs and fat in grams.
- Log your intake against these targets for a few weeks and adjust if your results don't match your goal.
Example
Input
Female, 28 years, 165 cm, 60 kg, moderately active, goal: cutOutput
≈1,860 kcal/day — Protein 140g, Carbs 140g, Fat 62gTDEE is estimated at around 2,070 kcal with Mifflin-St Jeor and a 1.55 activity multiplier, then reduced by about 500 kcal for a cutting deficit. Protein is set relatively high to protect muscle during the deficit, with carbs and fat filling the rest.
Typical macro splits by goal
| Goal | Calories vs TDEE | Protein | Typical split (P/C/F) |
|---|---|---|---|
| Cut (fat loss) | About -500 kcal | Higher (≈2.0-2.2 g/kg) | 35% / 35% / 30% |
| Maintain | At TDEE | Moderate (≈1.6-1.8 g/kg) | 30% / 40% / 30% |
| Bulk (muscle gain) | About +300-500 kcal | Moderate-high (≈1.8-2.0 g/kg) | 30% / 45% / 25% |
Related health calculators
Macros are built on top of your TDEE — for the resting-metabolism baseline or other body-composition figures, these calculators pair well with the macro calculator.
→ Calorie Calculator · BMR Calculator · Ideal Weight Calculator
Frequently Asked Questions
What are macronutrients?
Macronutrients ('macros') are the three categories of nutrients that provide energy: protein and carbohydrates each supply about 4 calories per gram, while fat supplies about 9 calories per gram. Together they make up your total calorie intake — tracking them in grams, not just total calories, lets you control body composition and energy levels more precisely.
What's the difference between cutting, maintaining and bulking macros?
Cutting uses a calorie deficit with a higher protein percentage to preserve muscle while losing fat. Maintaining keeps calories at your TDEE with a balanced, moderate split. Bulking uses a modest calorie surplus with enough protein to support muscle growth, while carbs and fat fuel training and recovery. The calorie target changes the most between goals; the protein-per-kg target changes less.
How much protein should I eat per day?
A common range for active adults is roughly 1.6-2.2 g of protein per kg of body weight per day, higher during a cutting phase to protect lean mass and lower toward maintenance. For someone who weighs 70 kg, that's about 112-154 g per day. Very high intakes beyond this range rarely add extra benefit.
Do carbs or fat matter as much as protein?
They matter for different reasons. Carbohydrates are the body's preferred fuel for higher-intensity exercise and help maintain training performance; fat supports hormone production and the absorption of fat-soluble vitamins. Neither should be cut extremely low for extended periods — the split shown here keeps both at levels that support training and general health.
Is this medical or nutrition advice?
No. This calculator provides general estimates for informational purposes only, based on standard formulas and common macro-split guidelines. It is not a substitute for professional advice — athletes, people with medical conditions, pregnant or breastfeeding women, and anyone with specific dietary needs should consult a doctor or registered dietitian.
Is my data stored anywhere?
No. The calculation runs entirely in your browser with JavaScript; nothing you enter is sent to a server, stored or logged.