How many calories do I need per day?
Estimate daily calorie needs from resting energy and activity, then adjust the result using your real weight trend.
There is no single calorie target that fits everyone. Daily needs vary with age, sex, height, weight, body composition, movement, training and life stage.
Most calculators first estimate resting energy expenditure, then apply an activity factor:
TDEE = resting energy estimate x activity factorTDEE is a useful starting estimate for maintenance. Eating below it tends to support weight loss over time; eating above it tends to support weight gain. The size of that gap and the quality of the diet matter, and extreme changes can be unsafe.
Activity selection is a common source of error. Base it on a normal week and do not count the same workout twice. Also avoid treating the output as an exact daily ceiling: energy expenditure varies from day to day.
Use the TDEE calculator with current measurements. Hold a consistent approach for two or three weeks, compare weekly average weights and make a small adjustment only if the trend differs from your goal.
Pregnancy, adolescence, eating disorders, significant illness and some medications require more individualized guidance than a general calculator can provide.