Lean Bulk Rate Calculator
Find a lean-bulk weight-gain rate for your experience level and the daily calorie surplus it takes.
How it works
weekly gain = body weight × rate% · daily surplus ≈ weekly gain × 500 kcal · intake = TDEE + surplus
A lean bulk aims to gain muscle while adding as little fat as possible, which means a modest calorie surplus and a slow, controlled rate of weight gain. Because your body can only build muscle so fast, beginners can gain quicker (around 0.5% of body weight a week) while advanced lifters should go slower (about 0.25%) to avoid piling on fat. This tool turns your rate into a weekly target and the daily surplus needed to hit it, using the approximation that a 500 kcal daily surplus adds roughly a pound a week.
Worked example
A 160 lb intermediate lifter targeting 0.375% a week aims for 0.6 lb per week. That needs about a 300 kcal daily surplus, so on a 2,500 kcal maintenance the target intake is roughly 2,800 kcal.
Frequently asked questions
How fast should I gain on a lean bulk?
Roughly 0.25–0.5% of body weight per week, faster for beginners and slower for advanced lifters. Gaining much quicker means a larger share of the weight is fat rather than muscle.
Why not just eat a huge surplus to grow faster?
Muscle-building has a speed limit set by training and recovery. Calories beyond a modest surplus mostly add fat, which you then have to diet off later.
Should I recalculate as I gain weight?
Yes. Both your target rate (a percentage of body weight) and maintenance calories rise as you get heavier, so revisit the numbers every few weeks and adjust intake to actual scale trends.
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This is a general educational estimate, not medical or dietary advice. Weight, body composition and energy needs respond differently for everyone — for a plan tailored to you, talk to a doctor or registered dietitian.