Macro Calculator
Calories decide whether you lose or gain weight — but macronutrients decide what that weight is made of. Protein, carbohydrates and fat are the three macros that make up every calorie you eat, and the split between them shapes your hunger, energy, muscle retention and training performance far more than most people realize. This free macro calculator turns your calorie target into clear daily gram targets for each macro.
Start by estimating your TDEE with the built-in Mifflin-St Jeor calculator — or switch to “I know my TDEE” and type it in directly. Choose your goal: a 20% deficit for fat loss, maintenance, or a 10% surplus for muscle gain. Then pick a diet preset that matches how you like to eat — Balanced, Low Carb, High Protein or Keto — or use the custom sliders to dial in your own protein/carb/fat percentages. You’ll instantly see your daily calories, grams and calories per macro, a visual split bar, and your protein intake per pound of body weight. Grams use the standard conversion factors: protein and carbs at 4 kcal per gram, fat at 9 kcal per gram. Recalculate whenever your weight, training or goal changes.
How to Use This Macro Calculator
- Estimate your TDEE with the built-in stats form (Mifflin-St Jeor equation), or switch to “I know my TDEE” and enter it directly.
- Choose your goal — Lose (20% deficit), Maintain, or Gain (10% surplus).
- Pick a diet preset, or choose Custom and drag the sliders to your own percentages.
- Read your daily calories plus protein, carb and fat targets in grams — results update instantly as you change any input.
Formulas & Assumptions
- Goal adjustments: Lose = TDEE × 0.80 · Maintain = TDEE × 1.00 · Gain = TDEE × 1.10
- Energy conversion (Atwater factors): protein 4 kcal/g · carbohydrates 4 kcal/g · fat 9 kcal/g
- TDEE engine: Mifflin-St Jeor BMR (men: 10×kg + 6.25×cm − 5×age + 5; women: −161) multiplied by an activity factor from 1.2 to 1.9 — the same method as our TDEE calculator. Source: Mifflin MD, St Jeor ST, et al., Am J Clin Nutr, 1990;51(2):241–247.
- Protein per pound: for active people aiming to build or retain muscle, research supports roughly 0.7–1.0 g per lb of body weight per day (≈1.6–2.2 g/kg; Morton et al., Br J Sports Med, 2018). Use the readout to sanity-check any preset.
- Custom percentages are normalized to 100% if the sliders don’t sum to exactly 100.
| Diet Preset | Protein | Carbs | Fat | Best For |
|---|---|---|---|---|
| Balanced | 30% | 35% | 35% | Everyday eating, general fitness |
| Low Carb | 40% | 20% | 40% | Fat loss with fewer blood-sugar swings |
| High Protein | 40% | 30% | 30% | Muscle retention while cutting |
| Keto | 35% | 5% | 60% | Ketogenic diets (≈25 g carbs at 2,000 kcal) |
FAQ
What are macronutrients?
Macronutrients are the three nutrient families that provide calories: protein and carbohydrates at 4 kcal per gram, fat at 9 kcal per gram. (Alcohol, where relevant, provides 7 kcal per gram.) Your macro split influences hunger, energy, muscle retention and training performance.
How much protein do I need per day?
For active people aiming to build or keep muscle, research supports roughly 0.7–1.0 g per pound of body weight (about 1.6–2.2 g/kg). A 2018 meta-analysis by Morton et al. in the British Journal of Sports Medicine found benefits plateaued near 1.6 g/kg/day. Check the per-pound readout under your results.
What do the diet presets mean?
Each preset sets protein, carbs and fat as a percentage of your daily calories: Balanced 30/35/35, Low Carb 40/20/40, High Protein 40/30/30, Keto 35/5/60. Choose Custom to set your own percentages with the sliders.
Is 5% carbs enough for keto?
At 2,000 kcal, 5% is 25 g of carbs per day — within the classic ketogenic range of 20–50 g. On higher-calorie targets, 5% can exceed 50 g; use the custom sliders to cap carbs at your preferred gram level.
Do I need to hit my macros exactly?
No — being within 5–10 g on each macro is fine for almost everyone. Consistency across weeks matters far more than any single day. Prioritize hitting your calorie and protein targets; let carbs and fat flex around them.