Bulking calculator
Work out how many calories to eat to build muscle. Choose how fast you want to gain, and get a daily target with a protein-first macro split.
- BMR & TDEE
Worked out from your age, size and training, or enter your own.
- Meal-by-meal split
Your daily target divided across meals, snacks and workout fuel.
- Macro estimate
Protein, carbs and fat based on your bodyweight.
How many calories do you need to bulk?
To build muscle efficiently you need a calorie surplus: eating more than your TDEE. CalBudge offers three paces: mild (10% above your TDEE), moderate (20% above) and aggressive (25% above).
A mild surplus, often called a lean bulk, keeps fat gain to a minimum. A bigger surplus can help if you struggle to gain weight, at the cost of more fat.
Protein and macros for bulking
Your results include a macro estimate: protein at 1.8 g per kg of bodyweight, fat at 25% of your calories, and carbohydrates filling the rest to fuel your training. The meal split includes pre- and post-workout meals.
How it works
- 01Tell us about you
Age, height, weight, sex and how often you train. Already know your TDEE? Skip straight to your goal.
- 02Pick a goal and pace
Cutting, bulking or maintaining, at a mild, moderate or aggressive pace.
- 03Get your budget
A daily calorie target split across your meals, with a macro estimate. Save it or copy it into your tracker.
How CalBudge calculates your calories
No black box. These are the exact formulas and numbers the calculator uses, so you can check the working.
1. Basal metabolic rate (BMR)
By default, BMR comes from the Mifflin-St Jeor equation, one of the most widely used formulas for estimating resting energy needs:
Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161If you enter your body fat percentage, CalBudge switches to the Katch-McArdle equation, which works from lean mass and tends to be more accurate for people who know their body composition:
370 + 21.6 × lean body mass (kg)2. Total daily energy expenditure (TDEE)
Your BMR is multiplied by an activity factor between 1.2 (sedentary) and 1.9 (very active), based on your gym and cardio sessions per week. If you add your average daily steps, the factor is nudged up or down slightly to match how much you move outside the gym.
3. Your daily target
To lose or gain weight, your TDEE is adjusted by the pace you choose:
| Pace | Cutting | Bulking |
|---|---|---|
| Mild | −10% | +10% |
| Moderate | −20% | +20% |
| Aggressive | −27.5% | +25% |
For safety, a cut never goes below 1.2 × your BMR, and no target ever goes below 1,200 calories a day. If your chosen pace would cross that line, CalBudge raises your target and tells you.
4. Macros
If you give your bodyweight, CalBudge estimates a macro split: protein at 1.8 g per kg of bodyweight, fat at 25% of your calories, and carbohydrates making up the rest.
5. Meal-by-meal split
Your daily target is divided across six eating occasions:
| Breakfast | ≈18% |
| Lunch | 25% |
| Dinner | 25% |
| Snack, pre-workout, post-workout | ≈11% each |
Skip a meal you don't eat and its calories are spread across the others in proportion to their size.
6. Time to your target weight
If you set a target weight, CalBudge estimates the timeline using roughly 7,700 calories per kilogram of body weight. Real progress varies with water weight, adherence and metabolic adaptation, so treat it as a rough guide.
Frequently asked questions
What is TDEE?
TDEE (total daily energy expenditure) is the number of calories you burn in a day, including exercise and everyday movement. Eating at your TDEE maintains your weight; eating below it loses weight, and above it gains weight.
What's the difference between BMR and TDEE?
BMR (basal metabolic rate) is what your body burns at complete rest. TDEE is your BMR multiplied by an activity factor that accounts for training and daily movement, so it is always higher.
How accurate is a calorie calculator?
Any formula is an estimate. Treat your number as a starting point: track your weight for two to three weeks, then adjust up or down by 100 to 200 calories if you are not moving in the direction you expect.
Can I use my own TDEE or BMR?
Yes. If you already know your TDEE, choose "Yes, I know my TDEE" at the start. If you know your BMR from a lab test or smart scale, enter it in the optional step and CalBudge will use it instead of a formula.
Can I use CalBudge with MyFitnessPal, MacroFactor or Cal AI?
Yes. On the results screen, choose "Export to app" to copy your calorie and macro targets in a format ready to paste into those apps. You can also download your budget as an image or PDF.
Do I need an account?
No. CalBudge is free and there is no signup. The calculation runs in your browser and your answers are not saved anywhere.
Ready to find your number?
It takes about a minute. Free, no signup.