How the muscle gain calculator works
We estimate your TDEE, then add 10% for a modest surplus. Protein is set at 1.6 g per kg of bodyweight (about 0.7 g per lb), the point where a large meta-analysis found extra protein stopped adding measurable muscle for most lifters. Fat is 25% of calories and carbs fill the rest, which leaves plenty of fuel for training. See the methodology for every formula.
Lean bulk vs. dirty bulk
Muscle grows slowly, so a large surplus mostly adds fat. A lean bulk uses a small surplus and accepts a slower scale so that more of the weight you gain is muscle and the cut that follows is shorter.
| Lean bulk | Aggressive bulk | |
|---|---|---|
| Surplus | About 5–10% above TDEE | 15–20%+ above TDEE |
| Weekly gain | About 0.25–0.5% of bodyweight | Often 0.75%+ of bodyweight |
| Best for | Most people who already train | Very lean beginners who struggle to eat enough |
How fast should you gain weight?
For most people a pace of roughly 0.25–0.5% of bodyweight per week is a sensible starting point: about 0.4–0.8 lb (0.2–0.4 kg) a week at 160 lb (73 kg). Beginners can usually gain toward the top of that range; experienced lifters closer to the bottom. Weigh yourself several mornings a week and compare weekly averages.
Adjusting your bulk
- Not gaining after 2–3 weeks? Add about 100–200 calories a day, mostly from carbs.
- Gaining much faster than planned? Remove 100–200 calories a day.
- Strength stalling? Check sleep and your training program before eating more.
- Recalculate after every 3–4 kg (7–9 lb) gained, because a heavier body burns more.
When to stop bulking
Many lifters end a bulk when their waist measurement has grown noticeably, when they feel their training is no longer improving, or after a set period of a few months. Then they hold maintenance for a few weeks or switch to a cut. There is no single correct body-fat cut-off.
Muscle Gain Macro Calculator FAQ
How do I calculate macros for muscle gain?
Estimate TDEE, add 5–10%, set protein at 1.6–2.2 g/kg (0.7–1 g/lb), set fat at 20–35% of calories and give the remainder to carbs.
What is a good macro split for bulking?
Roughly 20–25% protein, 50–60% carbs and 20–25% fat is common, but set protein in grams first and let the percentages follow. See the macro breakdown by goal.
Do I need more protein to build muscle?
More than the 0.8 g/kg minimum, yes, but not unlimited. Around 1.6 g/kg covers most people; the protein calculator shows your range.
Can I build muscle without a surplus?
Yes, especially beginners, people returning to training and people with more body fat. That approach is called body recomposition; the body recomp calculator sets it up with a small deficit and high protein.
Should I eat more on training days?
You can, but it is optional. Weekly totals matter more than daily precision, and the same target every day is easiest to follow.
Sources
- Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 2018.
- Jäger R, et al. International Society of Sports Nutrition position stand: protein and exercise. Journal of the ISSN, 2017.
- Iraki J, et al. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports, 2019.
General information only, not medical advice. Talk to a qualified healthcare professional before changing your diet, especially if you are under 18 or managing a medical condition.