TDEE calculator
Your total daily energy expenditure is roughly what you burn in a day, everything included. It is the number every calorie target is built from: eat under it to lose, over it to gain. This estimates it, then shows both targets.
Enter a body fat percentage and the calculation switches to Katch-McArdle, which works from lean mass instead of total weight and is the better fit for lifters.
- At complete rest (BMR)
- 1,768 kcal
- Fat loss target
- 2,240 kcal
- Lean gain target
- 3,040 kcal
An estimate from a published formula, not a measurement. Use it as a consistent yardstick for tracking change.
What the number is made of
Four things stack up into it. Your basal rate is the largest slice, roughly 60 to 70% of the total, and it is what your body spends staying alive. Digestion takes another 10% or so. Deliberate exercise, for most people, is smaller than they expect: an hour of hard lifting is a few hundred kilocalories, not a thousand.
The fourth slice is the one that ruins predictions. Non-exercise activity, everything from walking to fidgeting, varies by hundreds of kilocalories between two people of the same size, and it quietly falls when you diet. That is the single biggest reason a TDEE estimate drifts from reality over a cut.
Why the activity multiplier is the weak link
The resting-rate equations are reasonably accurate, generally within about 10% for most people. The activity multiplier is a blunt instrument bolted onto the end of them, and picking "active" instead of "moderate" moves the answer by hundreds of kilocalories.
The practical fix: pick the multiplier one step lower than your instinct, use the result for two weeks, and then correct from what the scale actually did. Measured drift beats a better guess.
Which equation this uses
- Mifflin-St Jeor (1990) when you leave body fat at 0. It uses weight, height, age and sex, and it is the equation most dietitians reach for first.
- Katch-McArdle when you enter a body fat percentage. It ignores everything except lean mass, which is why it handles a muscular 90 kg lifter and a sedentary 90 kg adult differently, where the first equation cannot.
If you know your body fat with any confidence, the second is the better estimate. If you are guessing at it, the first is safer, because a wrong body fat figure propagates straight into the answer.
How to correct it against reality
Eat at the estimate for two full weeks, weighing yourself under the same conditions each morning and comparing weekly averages rather than single days. If the average is flat, the estimate was right. If it moved, adjust by roughly 200 kcal in the opposite direction and repeat.
Two weeks is the minimum because water weight swamps fat change over shorter windows. A single week of data will convince you of things that are not true.
Questions people ask
How accurate is a TDEE calculator?
The resting portion is usually within 10%, but the activity multiplier can be off by 300 kcal or more in either direction. Treat the output as a starting point to test, not a number to trust. Two weeks of weight data tells you more than any equation.
Should I count my lifting sessions in the activity level?
Yes, that is what the level describes. But do not also add the session as extra calories on top. The multiplier already assumes those sessions happen, and double counting is the most common way people end up eating back a deficit they never created.
Does TDEE drop as I lose weight?
Yes, for two reasons: a smaller body costs less to run, and spontaneous movement tends to fall during a deficit. Recalculate every 4 to 5 kg of change rather than holding one number for a whole diet.
Why is my fitness tracker giving a different number?
Wearables estimate expenditure from heart rate and movement, which is a different method with its own error, and they generally read high for strength training. Pick one source and stay with it rather than averaging two estimates that disagree.
Related tools
Energy is the easy half
The hard half is progressive overload, session after session. Mekimeki tracks the training side: sets, reps, estimated 1RM and volume, free.
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