Weight Gain Calculator

Gaining weight on purpose is the same arithmetic as losing it run the other way: find what holds your weight steady, then eat a measured amount above it. Enter sex, age, height, weight and activity level along with the rate you want to gain at, and it returns a daily calorie target and the surplus inside that target. A second mode turns a goal weight and a daily surplus into the weeks it should take. Both lean on the 3,500 calories per pound rule of thumb and on population-average formulas, so the numbers are a starting point rather than dietary advice.