Calculator Inputs
Example Data Table
| Input | Example Value | Output |
|---|---|---|
| Sex, age | Male, 28 years | Katch-McArdle selected because body fat is provided |
| Weight, height | 78 kg, 178 cm | BMR ≈ 1,802 kcal/day |
| Body fat, activity | 15%, 1.55 | TDEE ≈ 2,793 kcal/day |
| Weekly gain target | 0.25 kg/week | Daily surplus ≈ 275 kcal/day |
| Protein, fat | 2.0 g/kg, 0.9 g/kg | Protein ≈ 156 g, fat ≈ 70.2 g |
| Total calorie target | Calculated result | Calories ≈ 3,068 kcal/day |
| Carbohydrates | Calculated from remaining calories | Carbs ≈ 453.1 g/day |
| Meals per day | 5 meals | Per meal ≈ 613 kcal, 31.2 g protein |
Formula Used
Lean Body Mass = Weight × (1 − Body Fat % ÷ 100)
Katch-McArdle BMR = 370 + (21.6 × Lean Body Mass in kg)
Male: BMR = 10W + 6.25H − 5A + 5
Female: BMR = 10W + 6.25H − 5A − 161
TDEE = BMR × Activity Factor
Daily Surplus = (Weekly Gain in kg × 7700) ÷ 7
Target Calories = TDEE + Daily Surplus
Protein = Body Weight in kg × Protein g/kg
Fat = Body Weight in kg × Fat g/kg
Carbs = (Target Calories − 4×Protein − 9×Fat) ÷ 4
This setup prioritizes protein and fat first, then assigns remaining calories to carbohydrates. That usually works well for muscle gain, training performance, and meal planning.
How to Use This Calculator
- Choose metric or imperial units.
- Enter sex, age, body weight, and height.
- Add body fat percentage for a more personalized BMR estimate.
- Select your activity factor based on your real weekly movement.
- Set training days, weekly gain target, protein target, and fat target.
- Choose how many meals you want per day.
- Press the calculate button to show your result above the form.
- Review calories, macro grams, meal split, and training versus rest day suggestions.
- Use the CSV or PDF button to save your plan.
- Update calories every two to three weeks using actual bodyweight changes.
Frequently Asked Questions
1) What is a bulking macro calculator?
It estimates calorie intake and daily protein, fat, and carbohydrate targets for gaining body weight with a muscle-building focus. It uses body data, activity, and a chosen weekly gain pace.
2) Why does body fat percentage improve the estimate?
Body fat allows the calculator to estimate lean body mass and use the Katch-McArdle equation. That often gives a more tailored BMR estimate than formulas based only on body weight, height, age, and sex.
3) What weekly gain target is reasonable for most people?
A moderate pace such as 0.15 to 0.35 kg per week is common for a controlled bulk. Faster rates can work, but they usually raise the chance of gaining more body fat.
4) Why are carbs calculated last?
Protein supports muscle repair and growth, while fat supports hormones and general health. After those needs are covered, the remaining calories usually go to carbohydrates for training energy and recovery.
5) Should training and rest day calories be different?
They can be. This calculator gives a simple split by slightly increasing training day calories and balancing rest days across the week. Many people find that higher training day carbs help performance and appetite management.
6) How often should I adjust my bulking calories?
Review bodyweight averages, gym performance, and waist changes every two to three weeks. If you are not gaining at the planned rate, increase calories modestly. If fat gain is too fast, reduce them slightly.
7) What if my carb result becomes zero?
That means your chosen protein and fat targets already use all available calories. Lower one of those settings or increase total calories. Otherwise, the plan may be hard to sustain during demanding training.
8) Is this calculator suitable for medical nutrition planning?
No. It is a general educational tool for fitness nutrition planning. Anyone with diabetes, kidney disease, digestive disorders, or physician-directed diet needs should use professional guidance before making large intake changes.