BodyCalTDEE, in plain English
TDEE stands for Total Daily Energy Expenditure — the total number of calories your body burns in a full day. It's the number that decides whether you gain, lose, or maintain weight: eat below it and you lose, eat above it and you gain, eat at it and you stay the same. If you only learn one number for managing your body, make it this one.
Your TDEE isn't a single fixed figure. It rises on days you move more and falls as you lose weight, which is why it's worth recalculating every few weeks rather than treating it as set in stone.
The parts that add up to your TDEE
TDEE is built from four components. The biggest is your basal metabolic rate (BMR) — the 60–70% of calories you burn just staying alive. Next is physical activity, both exercise and everyday movement. Then there's the thermic effect of food, the energy used to digest what you eat (about 10%), and finally small involuntary movements like fidgeting.
For practical purposes, we estimate BMR with a validated formula and multiply by an activity factor to capture the rest. It's an estimate, but a good one.
How TDEE is calculated
The standard method starts with the Mifflin–St Jeor equation, which predicts your BMR from your age, sex, height, and weight. That BMR is then multiplied by an activity multiplier — 1.2 for sedentary up to 1.9 for very active — to give your TDEE.
For example, a woman with a BMR of 1,450 calories who is lightly active (×1.375) has a TDEE of roughly 1,994 calories. Our TDEE calculator does this instantly and even shows your number at every activity level so you can see how much movement is worth.
Turning TDEE into a plan
Once you know your maintenance calories, the rest is arithmetic. Subtract about 500 calories a day for steady fat loss of roughly a pound a week; eat at maintenance to hold your weight; add a small surplus to build muscle. From there, split those calories into protein, carbs, and fat to shape how you look and feel.
The most common mistake is overestimating activity, which inflates your TDEE and quietly stalls progress. Be honest about how active you really are, track your weight for a few weeks, and adjust based on what the scale actually does.