Weight Gain Calculator
Building up? Pick a goal weight and pace and see when you'll hit it — plus the daily calorie surplus to aim for.
Your results
Fuel your bulkHow long will it take to gain the weight?
This weight gain calculator projects the date you'll hit your goal weight from your chosen weekly pace, and the daily calorie surplus that pace requires. For anyone bulking, the pace decision is the whole game: it determines how much of what you gain is muscle versus fat.
How it works
Using the same energy arithmetic as weight loss (~7,700 kcal per kg), your weekly gain target converts to a daily surplus — 0.25 kg per week ≈ 275 kcal per day above maintenance. The calculator divides your total goal by the pace to give a finish date.
What's a realistic rate of muscle gain?
Slower than most people want to hear. Reviews of resistance-training research suggest beginners can gain roughly 0.25–0.5 kg of actual muscle per week in their first months, intermediates about half that, and advanced lifters a fraction more per month. Gaining faster than ~0.5 kg per week almost guarantees the extra is fat. That's why the "Lean" pace exists — a modest surplus with hard training is the highest muscle-to-fat ratio you can buy.
Frequently asked questions
Why am I not gaining even though I "eat a lot"?
Appetite is unreliable. Hardgainers almost always overestimate intake — a few high-calorie days followed by unconscious under-eating. Track for two weeks; the surplus is either there or it isn't. Liquid calories (shakes, milk, oats blended in) fix most stalls.
Do I need a dirty bulk?
No. Past the surplus your body can turn into muscle, extra calories are stored as fat you'll have to diet off later. The evidence favours a lean bulk: ~10% over maintenance, high protein, progressive overload.
References
- Iraki J, Fitschen P, Espinar S, Helms E. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports (Basel). 2019;7(7):154.
- Garthe I, Raastad T, Refsnes PE, Sundgot-Borgen J. Effect of nutritional intervention on body composition and performance in elite athletes. Eur J Sport Sci. 2013;13(3):295–303.
Related
These results are estimates for healthy adults and are not medical advice. Consult a health professional before making major changes to your diet or training.
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