About the Macro calculator
Macronutrients, or macros, are the three nutrients that supply calories: protein, carbohydrate and fat. This calculator estimates your daily calorie target from your body details, activity and goal, then splits it into grams of each macro.
Choose from five diet styles, from balanced to keto. You also see your protein per pound or kilogram of body weight and a chart of where your calories come from. It's a planning aid that you can adjust to your own tastes and needs.
How to use it
- Choose Units, select your Sex and enter your Age, height and Weight.
- Pick your Activity level for a typical week.
- Choose a Goal: maintain, lose slowly, lose, or build muscle.
- Choose a Diet style, then read your daily grams of protein, carbs and fat.
The formula
First the calorie target, then the split into grams.
Calories = Mifflin–St Jeor BMR × activity factor + goal adjustmentProtein g = calories × protein% ÷ 4 Carbs g = calories × carb% ÷ 4 Fat g = calories × fat% ÷ 9
- Goal adjustments: 0 (maintain), −250 kcal (lose slowly), −500 kcal (lose) or +300 kcal (build muscle).
- The calorie target is never set below 1,200 kcal for women or 1,500 kcal for men.
- Protein and carbohydrate provide about 4 kcal per gram; fat about 9 kcal per gram.
| Diet style | Protein | Carbs | Fat |
|---|---|---|---|
| Balanced | 30% | 40% | 30% |
| High protein | 40% | 35% | 25% |
| Low carb | 40% | 20% | 40% |
| Keto | 25% | 5% | 70% |
| Low fat | 25% | 55% | 20% |
Worked example
A 35-year-old woman, 5 feet 6 inches and 160 lb, with moderate activity, has an estimated TDEE of about 2,228 kcal. With the lose goal (−500 kcal), her target is about 1,728 kcal.
On the balanced split, protein is 1,728 × 30% ÷ 4 ≈ 130 g, carbs are 1,728 × 40% ÷ 4 ≈ 173 g and fat is 1,728 × 30% ÷ 9 ≈ 58 g. That's about 0.81 g of protein per pound of body weight.
Choosing a diet style
Research generally finds that, for weight change, total calories matter more than the exact macro split. The best split is usually the one you can enjoy and keep up. Still, the mix affects how full you feel, your training and your food choices.
Balanced suits most people and leaves room for a wide range of foods. High protein can help with fullness and with keeping muscle while losing weight, especially alongside strength training. Low carb and keto shift energy toward fat. Keto at 5% carbs is very restrictive and can affect people on some medications, including diabetes and blood pressure drugs, so check with a doctor before starting it. Low fat keeps fat at 20% while giving more carbohydrate, which some endurance athletes prefer.
Whatever the split, quality matters: plenty of vegetables, fruit, whole grains, legumes and unsaturated fats. If you have kidney disease, are managing a medical condition, or need tailored advice, a registered dietitian is the best guide. To see the calorie side in more detail, use the calorie calculator.
Frequently asked questions
How much protein do I need a day?
Needs vary with body size, age and activity. Active people and those trying to keep muscle while losing weight often aim higher than the general minimum, and the protein-per-weight row helps you compare.
Why are fat grams so much lower than carb grams?
Fat has about 9 kcal per gram, more than twice the 4 kcal of protein or carbs. The same share of calories from fat therefore weighs less.
What happens if my calorie target is very low?
The calculator won't set a target below 1,200 kcal for women or 1,500 kcal for men. If the math would go lower, it uses that minimum instead.
Is keto safe?
Many healthy adults follow it without problems, but it is very restrictive. If you take medication for diabetes or blood pressure, or have kidney or liver issues, speak to a doctor first.
Do I have to hit my macros exactly?
No. Being within roughly 5 to 10 grams most days is plenty for most goals. Consistency over weeks matters more than precision on any single day.
Last updated October 24, 2026. Results are estimates for education and planning — see our disclaimer.