Work out calorie surplus for weight gain instantly with clear inputs, formula shown and shareable results.
Gaining tissue requires energy above maintenance, roughly 7700 kcal per kilogram. Adding 5 kg over 20 weeks means 0.25 kg a week, needing a 275 kcal daily surplus on top of a 2600 kcal maintenance - about 10.6% above maintenance. Larger surpluses accelerate gain but shift the ratio towards fat rather than muscle.
Weekly gain
weekly = target gain / weeks
Daily surplus
surplus = weekly gain x 7700 / 7 kcal
These figures are population-average estimates, not a medical assessment or diagnosis. Body composition equations carry errors of several percentage points, and healthy ranges vary with age, ethnicity, muscularity and medical history. Discuss weight or body composition goals with a qualified clinician or dietitian.
For muscle gain, 10-20% above maintenance, or roughly 0.25-0.5% of body weight per week. Bigger surpluses mostly add fat.
Not exactly - lean tissue holds more water and stores fewer calories per kilogram, so gaining muscle needs somewhat less energy per kilogram than losing fat releases.