General estimate
TDEE Calculator
Estimates daily energy use by applying an activity factor to BMR.
How this estimate is calculated
Mifflin–St Jeor resting energy multiplied by an activity factor between 1.2 and 1.725.
How to use the result
Treat it as a starting point to compare against how you actually feel and what you actually eat. Estimates are most useful for spotting a large gap, not for chasing a precise number.
What this cannot tell you
Activity factors are coarse bands. Two people who pick the same band can differ by several hundred calories a day.
Estimates, not measurements: this tool runs a population equation, so it describes a typical person with your inputs rather than measuring you. Where a number drives a decision about a diagnosed condition or medication, have a dietitian or clinician sanity-check it against your history.