TDEE Calculator · Practical guide
How Many Calories Should I Eat to Gain Muscle?
A modest surplus above your TDEE builds muscle without piling on fat — here are the numbers.
At a glance
The Short Answer
To gain muscle, eat 250-500 calories above your TDEE — about a 10-20% surplus — and pair it with resistance training. That supports weight gain of roughly 0.5-1 lb per week at most; gaining faster mostly adds fat, not muscle.
Interactive tool
TDEE Calculator
Enter your own values, then compare the result with the examples below.
Activity Breakdown
| Activity Level | Multiplier | TDEE (calories/day) |
|---|---|---|
| Sedentary | 1.2 | -- |
| Lightly active | 1.375 | -- |
| Moderately active | 1.55 | -- |
| Very active | 1.725 | -- |
| Super active | 1.9 | -- |
Worked Example
A 30-year-old woman at 5'5" (165 cm) and 143 lb (65 kg), training 3-5 days per week, has a TDEE of about 2,124 kcal/day. Her muscle-gain targets:
| Approach | Daily Calories | Expected Gain |
|---|---|---|
| Maintenance (her TDEE) | 2,124 kcal | Weight stable |
| Lean bulk (+250 kcal) | 2,374 kcal | ~0.5 lb/week |
| Standard bulk (+500 kcal) | 2,624 kcal | ~1 lb/week |
| 20% surplus | 2,549 kcal | ~0.85 lb/week |
Why Small Surpluses Win
Muscle growth is slow — even beginners with great training add only about 1-2 lb of actual muscle per month. The body cannot use a huge calorie surplus to build muscle faster, so anything beyond what growth requires gets stored as fat. A 250-500 kcal surplus covers the energy cost of building new tissue with minimal spillover.
Making the Surplus Count
- Lift progressively: without a training stimulus, a surplus just becomes fat.
- Eat enough protein: roughly 0.7-1 g per pound of body weight per day supports muscle repair.
- Recalculate as you grow: every 10 lb gained raises your TDEE, so update the calculator and your target together.
Run your own stats above to get your exact surplus range.
Frequently Asked Questions
Can I gain muscle without a calorie surplus?
Beginners and people returning to training can build some muscle at maintenance or even in a small deficit, especially with high protein. Beyond that stage, a modest surplus of 250-500 kcal is far more reliable.
How do I know if I am gaining muscle or fat?
Watch the rate: gaining faster than about 1 lb per week is mostly fat. Strength trending up in the gym while your waist stays roughly stable is the sign of a lean bulk.
Should I eat more on workout days only?
It is not necessary. Muscle is built during recovery over the whole week, so a steady daily surplus works just as well and is simpler to track. Consistency matters more than timing.
How long should a bulk last?
Commonly 8-16 weeks, or until you have gained 5-10 lb. Longer bulks tend to add disproportionate fat, after which many people switch to a small deficit to trim down.