Macro Calculator
Split your daily calories into protein, carbs and fat and get exact gram targets for maintaining, losing or gaining weight.
Macro Calculator — input your values
What does this health calculator do?
This macro calculator splits your daily calorie target into protein, carbohydrates and fat using a balanced 30/40/30 split, then converts each percentage into grams using the energy content of each nutrient — 4 kcal per gram for protein and carbs, 9 kcal per gram for fat.
It adjusts your entered calorie target for your goal: calories are reduced by 20% for weight loss, kept the same for maintenance, or increased by 10% for weight gain. You get the grams for every macronutrient, a calorie table and a visual split.
Macro splits are a starting framework, not a prescription. The 30/40/30 ratio suits many people, but protein needs vary with training and goals, and individual responses differ. Consult a dietitian for personalized guidance.
Formula and variables
Goal adjustment: weight loss uses 80% of the entered calories, maintenance 100%, weight gain 110%.
| Symbol | Meaning |
|---|---|
| Protein | 30% of calories ÷ 4 (4 kcal per gram) |
| Carbs | 40% of calories ÷ 4 (4 kcal per gram) |
| Fat | 30% of calories ÷ 9 (9 kcal per gram) |
Worked example
A 2,000 kcal target for maintenance at a body weight of 70 kg.
- Calories stay at 2,000 kcal.
- Protein = 30% × 2,000 = 600 kcal ÷ 4 = 150 g.
- Carbs = 40% × 2,000 = 800 kcal ÷ 4 = 200 g.
- Fat = 30% × 2,000 = 600 kcal ÷ 9 = 66.7 g.
- Protein per kg: 150 ÷ 70 = 2.1 g/kg, within the recommended 1.6–2.2 g range.
Answer: 150 g protein, 200 g carbs, ~67 g fat per day.
Tips and common mistakes
Tips
- Prioritize protein at every meal to preserve muscle, especially while losing weight.
- Use a food scale to measure portions — gram targets are only useful if you log accurately.
- Adjust the split over time; if you feel low on energy during training, shift some fat calories to carbs.
- Hit your weekly average rather than obsessing over each individual day.
Common mistakes to avoid
- Forgetting that fat has more than double the calories per gram of protein or carbs.
- Chasing gram targets with junk food — food quality still matters.
- Setting protein far above 2.2 g/kg while neglecting carbs, which fuel training.
Macro Calculator — frequently asked questions
What are macros?
Macronutrients are the three nutrients that supply calories: protein and carbohydrates at 4 kcal per gram, and fat at 9 kcal per gram. Their split determines how those calories are used.
How many grams of protein do I need?
Most research supports 1.6 to 2.2 g per kilogram of body weight per day for active adults, which is higher than the minimum for general health.
Why is the calculator reducing my calories for weight loss?
A 20% reduction below maintenance is a common, sustainable deficit for weight loss. You can adjust the starting calorie number if you prefer a different deficit.
Does it matter where my calories come from?
Yes — macro splits influence muscle retention, energy levels and satiety. A balanced split like 30/40/30 is a sensible default for most people.
Can I customize the percentages?
This calculator uses a fixed 30/40/30 split, but you can recalculate with a different calorie target to simulate other ratios.
Should I track macros forever?
No — many people track for a few weeks to learn portion sizes, then rely on that knowledge. Long-term tracking is a personal choice.