Weight Gain Calorie Calculator
Calculate the daily calories you need to gain weight. Estimates your maintenance (TDEE) and adds a lean surplus, with a protein target for healthy gains.
By Jonas Lindemann · Updated · How we build our calculators
2955kcal/day
TDEE 2605 kcal + 350 kcal surplus
1681
BMR
127g
protein
427g
carbs
82g
fat
Note: A modest surplus of 250-500 kcal favors lean mass over fat. Protein is anchored near 1.8 g/kg. Weigh yourself weekly and adjust calories if you aren't gaining about 0.25-0.5% of body weight per week.
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Calculation Method
Gaining weight cleanly is the same arithmetic as losing it, run in reverse: you must eat more energy than you burn. This calculator first estimates your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation, then adds a modest calorie surplus sized to favor lean mass over fat. It also sets a protein target so the extra calories build muscle rather than padding.
The Formula
Mifflin-St Jeor estimates your Basal Metabolic Rate (BMR), the calories you burn at rest. Multiplying by an activity factor gives TDEE; adding a surplus gives your gaining target.
BMR (women) = 10×kg + 6.25×cm − 5×age − 161
TDEE = BMR × activity factor
Target = TDEE + surplus (250–500 kcal)
- Conservative (+250): slowest, leanest gaining for experienced lifters.
- Standard (+350): a balanced default for most people.
- Faster (+500): quicker scale gains with more fat to manage.
Worked Example
A 28-year-old man, 178 cm, 70 kg, training 3–5 days a week (factor 1.55):
- BMR = 10×70 + 6.25×178 − 5×28 + 5 = 1,677 kcal
- TDEE = 1,677 × 1.55 = 2,600 kcal
- Target (standard +350) = 2,950 kcal/day
- Protein at 1.8 g/kg = 70 × 1.8 = 126 g/day
Expected Gaining Rate
| Surplus | Weekly gain | Best for |
|---|---|---|
| +250 kcal | ~0.2 kg | Advanced lifters |
| +350 kcal | ~0.3 kg | Most people |
| +500 kcal | ~0.45 kg | Hard gainers |
Making the Calories Count
A surplus only builds muscle if you train. Pair these calories with progressive resistance training, hit your protein target spread across the day, and prioritize nutrient-dense foods. Track your weekly average body weight and nudge calories up if the scale stalls for two weeks.
Note: This is an educational estimate, not medical or dietary advice. Calorie needs vary between individuals. Consult a registered dietitian or healthcare professional before making major changes to your diet.
Frequently Asked Questions
Eat above your maintenance (TDEE). A surplus of about 300-500 calories per day supports roughly 0.25-0.5 kg of gain per week while limiting fat gain. Larger surpluses add weight faster but more of it is fat.
For lean gains, aim for about 0.25-0.5% of body weight per week. Faster gains increase the fat share. Pair the surplus with resistance training and adequate protein to favor muscle.
Around 1.6-2.2 g of protein per kg of body weight per day supports muscle growth. The calculator includes a protein target alongside your calorie goal.