Calculator Inputs
Formula Used
1) Basal Metabolic Rate: The calculator uses the Mifflin-St Jeor equation.
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
2) Total Daily Energy Expenditure: TDEE = BMR × activity multiplier
3) Goal Calories: For muscle gain, calories increase by the selected percentage. For fat loss, calories decrease by that percentage.
4) Protein: Protein = body weight in kg × selected grams per kilogram, or 30% of total calories ÷ 4
5) Fat: Fat = body weight in kg × selected grams per kilogram
6) Carbohydrates: Carbs = remaining calories after protein and fat ÷ 4
How to Use This Calculator
- Choose whether your goal is muscle gain or fat loss.
- Enter sex, age, height, and weight using your preferred units.
- Select your normal activity level for a realistic energy estimate.
- Set protein and fat targets based on your preferred intake style.
- Choose the calorie adjustment percentage for bulk or cut intensity.
- Enter meals per day to get a practical meal-by-meal breakdown.
- Click the calculate button to show results above the form.
- Review the chart, table, and export options for planning.
Example Data Table
| Profile | Goal | Weight | Activity | Calories | Protein | Fat | Carbs |
|---|---|---|---|---|---|---|---|
| Person A | Muscle Gain | 70 kg | Moderate | 2710 kcal | 140 g | 56 g | 389 g |
| Person B | Fat Loss | 82 kg | Light | 2085 kcal | 164 g | 57 g | 200 g |
| Person C | Muscle Gain | 60 kg | Active | 2528 kcal | 120 g | 48 g | 376 g |
Frequently Asked Questions
1. Can this calculator help both bulking and cutting?
Yes. Select muscle gain for a calorie surplus or fat loss for a calorie deficit. The calculator then adjusts your calories and macro targets automatically.
2. Which BMR equation is used here?
It uses the Mifflin-St Jeor equation. This method is widely used for estimating resting calorie needs from age, sex, height, and weight.
3. Why is protein set by body weight?
Protein needs scale well with body size. Using grams per kilogram helps support muscle retention during fat loss and muscle growth during gaining phases.
4. What happens if my fat target is high?
A higher fat target uses more calories, leaving fewer calories available for carbohydrates. The tool automatically recalculates carb grams after protein and fat are set.
5. Should I choose a large calorie adjustment?
Usually no. Moderate surpluses and deficits are easier to sustain. Very aggressive changes may reduce adherence, training performance, or recovery quality.
6. Are meal targets necessary?
Not strictly. Daily totals matter most. Meal targets simply make the plan easier to distribute across breakfast, lunch, dinner, and snacks.
7. Does this calculator account for medical conditions?
No. It provides general planning estimates. People with diabetes, kidney disease, digestive issues, or other conditions should seek personalized guidance.
8. How often should I update my macros?
Review every two to four weeks, or sooner if body weight, activity, training volume, or progress changes meaningfully.