🔥 TDEE Calculator
Total daily energy expenditure is everything you burn in 24 hours. This works it out from the Mifflin-St Jeor equation and your real activity level, then splits it into the four components and gives targets for losing, maintaining and gaining.
Total daily energy expenditure, and the four things that make it up
TDEE is everything you burn in twenty-four hours. It is the number that decides whether you gain, lose or stay the same, and it is not one thing but four, in very uneven proportions.
| Component | Share of TDEE | What it is |
|---|---|---|
| Basal metabolic rate | 60–70% | Keeping you alive at complete rest |
| Activity thermogenesis | 15–30% | Walking, fidgeting, chores and deliberate exercise |
| Thermic effect of food | about 10% | The energy used digesting what you eat |
| Adaptive thermogenesis | varies | Adjustments to cold, overfeeding or restriction |
Most people assume exercise is the large piece. For a desk worker training four times a week it is usually under 15% of the total, while basal metabolism is around two thirds. That is why a single missed workout barely registers and a week of unusually low general movement does.
How this is calculated
The Mifflin-St Jeor equation gives basal rate, then an activity multiplier scales it up:
Men: BMR = 10w + 6.25h − 5a + 5 Women: BMR = 10w + 6.25h − 5a − 161
Weight in kilograms, height in centimetres, age in years. Mifflin-St Jeor replaced the older Harris-Benedict equation because it predicts measured values more accurately in modern populations, and it is what most dietitians use.
Choosing the activity multiplier honestly
| Multiplier | Level | A realistic description |
|---|---|---|
| 1.2 | Sedentary | Desk job, car commute, under 5,000 steps a day |
| 1.375 | Lightly active | Desk job plus 1–3 workouts, or 7,000–9,000 steps |
| 1.55 | Moderately active | 3–5 workouts a week, or a job on your feet |
| 1.725 | Very active | 6–7 hard sessions, or manual work plus training |
| 1.9 | Extremely active | Physical job and twice-daily training |
Almost everyone picks a level too high. If your weight is not moving the way the calculation predicts after three weeks, the multiplier is the input most likely to be wrong, not the equation.
NEAT: the component nobody counts
Non-exercise activity thermogenesis covers everything you do that is not sleeping, eating or deliberate exercise. Research has found it varies by up to 2,000 calories a day between individuals of similar size, which dwarfs the difference a few gym sessions make. It also falls quietly during a diet: people move less without noticing, which is a large part of why weight loss slows.
Setting a target from TDEE
Work in percentages rather than fixed numbers. A 500-calorie deficit is 20% for someone burning 2,500 and 33% for someone burning 1,500, and the second is much harder to hold. A deficit of 15% to 25% suits most people, and a surplus of about 10% is enough to build muscle without adding unnecessary fat.
A worked example
A 32-year-old man, 178 cm, 80 kg, training four times a week. BMR = 800 + 1,112 − 160 + 5 = 1,757. At a 1.55 multiplier, TDEE is 2,724 calories. A 20% deficit gives 2,179 a day. After losing 6 kg his BMR falls to about 1,697 and TDEE to 2,631, so the target drops to 2,105 to keep the same deficit.
This page explains published formulas and population averages. It is general information, not medical advice. Talk to a doctor or a registered dietitian before changing how you eat or train.
Frequently Asked Questions (FAQs)
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest, around two thirds of the total. TDEE is BMR plus everything else: movement, exercise and digestion. You eat against TDEE, not BMR.
How accurate is this calculation?
The Mifflin-St Jeor equation predicts measured BMR within 10% for about seven people in ten. Add the uncertainty in the activity multiplier and a TDEE estimate can reasonably be out by 200 to 300 calories. Use it as a starting point and adjust from what the scale actually does over three weeks.
Why has my TDEE dropped?
Three reasons compound during weight loss: a smaller body costs less to maintain, spontaneous movement falls, and the body becomes slightly more efficient. Together they can reduce TDEE by more than the weight loss alone predicts, which is why a deficit that worked in month one stops working in month four.
Should I eat back exercise calories?
Only partially. Trackers and gym machines overestimate, sometimes by 30%. If your activity multiplier already reflects your training, those calories are counted once; eating them back counts them twice.
Does muscle really raise my TDEE much?
Less than the internet suggests. A kilogram of muscle burns around 13 calories a day at rest against 4.5 for fat, so five kilograms of muscle adds roughly 65 calories a day. The real benefit of resistance training in a deficit is keeping the muscle you have.
How often should I recalculate?
Every 4 to 5 kilograms of weight change, or whenever your training or job changes materially. Recalculating keeps the deficit at the percentage you intended rather than letting it quietly shrink.