Calorie and TDEE Calculator
Estimate daily calorie needs from age, sex, size, and activity using the Mifflin-St Jeor equation.
What it does
Daily calorie needs come in two layers. Basal metabolic rate, or BMR, is what the body burns at full rest to run the brain, organs, and basic cell work. Total daily energy expenditure, or TDEE, adds everything else: walking, work, training, and digestion.
This page estimates BMR with the Mifflin-St Jeor equation, published in 1990 and still the most used formula in clinics because later reviews found it closer to measured values than older equations. It then multiplies BMR by an activity factor to reach TDEE.
The tool also prints two starting targets: TDEE minus 500 for a loss near half a kilo per week, and TDEE plus 250 for a slow gain. These are planning numbers. Real weight data over two to three weeks always beats a formula, so adjust up or down by 100 to 200 kcal when the scale disagrees.
How to use
- Enter age, sex, height, and weight. Morning weight before eating is the most stable.
- Pick the activity level that fits a normal week, not your hardest week.
- Read BMR first for context, then TDEE as the maintenance line.
- For loss, eat near the loss target. For gain, eat near the gain target. Hold each for two to three weeks before judging.
Formula
- 10 x weight
- Daily cost of body mass in kg, the largest term.
- 6.25 x height
- Size term in cm. Taller bodies burn more at rest.
- 5 x age
- Burn falls with age, subtracted yearly.
- +5 / -161
- Sex constant. Male bodies average more lean mass.
- activity 1.2-1.9
- Multiplier from desk bound to hard physical work.
Weight counts most, then height, then age. The male and female constants differ because, at equal size, men average more lean mass, which burns more at rest. Activity factors are rough by design: 1.2 for desk bound days, 1.55 for three to five workouts a week, 1.9 for hard physical work plus training.
Worked example
Example: 30 year old man, 180 cm, 80 kg, moderate activity
Each step below uses the male form of the equation, then the moderate factor of 1.55.
- Weight term: 10 x 80 = 800.
- Height term: 6.25 x 180 = 1125.
- Age term: 5 x 30 = 150, then add the male constant 5.
- BMR = 800 + 1125 - 150 + 5 = 1780 kcal.
- TDEE = 1780 x 1.55 = 2759 kcal, rounded to 2759.
- Loss target = 2759 - 500 = 2259 kcal. Gain target = 2759 + 250 = 3009 kcal.
Reference table
| Factor | Label | Typical week |
|---|---|---|
| 1.2 | Sedentary | Desk job, almost no planned exercise |
| 1.375 | Light | One to three easy workouts |
| 1.55 | Moderate | Three to five workouts |
| 1.725 | Very active | Six to seven hard sessions |
| 1.9 | Extra active | Physical job plus daily training |
Limits
- Estimates run 10 to 15% off for typical adults either way.
- Weak for very muscular or obese builds.
- Activity factors are rough by design, not measured.
- Illness, medicines, and hormones shift real burn.
Common mistakes
- Choosing the hardest training week instead of a normal one, which inflates TDEE by several hundred kcal.
- Counting exercise calories twice: once in the activity factor and again from a watch.
- Using current weight while aiming far away. Recompute every 4 to 5 kg of change.
- Eating below BMR for long stretches without supervision, which often backfires through hunger and fatigue.
- Ignoring liquid calories, oils, and sauces when comparing intake to the target.
Try it yourself
Quick checks. Answers sit tucked under each question.
Woman, 25 years, 165 cm, 60 kg, sedentary. BMR and TDEE?
BMR = 600 + 1031.25 - 125 - 161 = about 1345. TDEE = 1345 x 1.2 = about 1614 kcal.
Loss target at 2400 TDEE?
2400 - 500 = 1900 kcal a day.
Questions
BMR or TDEE: which one do I eat to?
Eat to TDEE for maintenance, below it for loss, above it for gain. BMR is a floor for context, not a diet target on its own.
Why Mifflin-St Jeor and not another equation?
Reviews against lab measured resting burn found it closer on average than the older Harris-Benedict form, mainly for adults of typical build. Very muscular or obese people still get better numbers from measured testing.
How fast should weight move?
A loss near 0.5% of body weight per week suits most people. Faster loss is possible but harder to hold and more likely to cost muscle.
Do I add back workout calories?
No. The activity factor already holds training. Adding watch calories on top counts the same burn twice.
When should I recalculate?
After 4 to 5 kg of change, after a big schedule shift, or when weight stalls for three full weeks.