🔥 TDEE & Calorie Calculator
A TDEE calorie calculator using Mifflin-St Jeor for BMR, with targets for loss, maintenance or gain — and how wide the activity multiplier error is.
🎯 Daily Calorie Targets for Your Goal
🥗 Daily Macronutrient Split (Maintenance)
What TDEE & Calorie Calculator Does
Total Daily Energy Expenditure is the number of calories your body uses in a day. It is built from a resting figure — the energy needed to keep you alive at complete rest — multiplied by a factor reflecting how much you move.
This calculator uses the Mifflin-St Jeor equation, published in 1990 from indirect calorimetry on 498 healthy adults. It replaced the 1919 Harris-Benedict equation as the default because Harris-Benedict was found to overestimate resting expenditure by about 5% in that same study.
Two things are worth knowing before you trust the output. The equation explains about 71% of the variance in resting expenditure, meaning individual results vary considerably around the prediction. And the activity multiplier is the crudest part of the whole calculation — most people overestimate it.
How to Use TDEE & Calorie Calculator
- Choose Metric (kg/cm) or Imperial (lbs/ft) units and select your gender
- Enter your age, current body weight, and height
- Select your average weekly physical activity level
- View your daily maintenance calories (TDEE) and BMR
- Check recommended daily calorie targets for mild, moderate, or aggressive weight loss and muscle building
Formula Used by TDEE & Calorie Calculator
Resting energy expenditure (Mifflin-St Jeor, 1990)
Men: REE = 10W + 6.25H − 5A + 5 Women: REE = 10W + 6.25H − 5A − 161
- W
- Body weight in kilograms
- H
- Height in centimeters
- A
- Age in years
- REE
- Resting energy expenditure in kcal per day
Worked example
A 35-year-old man, 80 kg, 180 cm.
- 10 × 80 = 800
- 6.25 × 180 = 1,125
- 5 × 35 = 175
- 800 + 1,125 − 175 + 5 = 1,755
Result: REE = 1,755 kcal/day at complete rest, before any activity.
Total daily energy expenditure
TDEE = REE × activity_factor
- activity_factor
- Ranges from 1.2 (sedentary) to 1.9 (very heavy training) — see the table below
Worked example
The same man, training moderately three to five days a week (factor 1.55).
- 1,755 × 1.55 = 2,720
Result: TDEE ≈ 2,720 kcal/day to maintain weight. A 500 kcal deficit puts him at about 2,220 kcal.
Activity Multipliers
This is the least precise part of the calculation. "Moderately active" means genuinely training three to five days a week, not intending to. When unsure, pick the lower factor and adjust from measured results.
| Level | Factor | Describes |
|---|---|---|
| Sedentary | 1.20 | Desk work, little or no deliberate exercise |
| Lightly active | 1.375 | Light exercise 1–3 days a week |
| Moderately active | 1.55 | Moderate exercise 3–5 days a week |
| Very active | 1.725 | Hard exercise 6–7 days a week |
| Extra active | 1.90 | Physical job plus hard daily training |
What a Calorie Deficit Actually Produces
Based on the conventional figure of roughly 7,700 kcal per kilogram of body fat. Real loss is slower than this arithmetic suggests, for the reasons in the limitations below.
| Daily deficit | Weekly deficit | Predicted loss per week | Assessment |
|---|---|---|---|
| 250 kcal | 1,750 kcal | ~0.23 kg (0.5 lb) | Slow, easy to sustain |
| 500 kcal | 3,500 kcal | ~0.45 kg (1 lb) | The standard recommendation |
| 750 kcal | 5,250 kcal | ~0.68 kg (1.5 lb) | Aggressive; hunger becomes a factor |
| 1,000 kcal | 7,000 kcal | ~0.91 kg (2 lb) | Hard to sustain; raises muscle-loss risk |
Where Your Daily Energy Goes
Approximate shares for a typical moderately active adult.
| Component | Share of TDEE | What it is |
|---|---|---|
| Basal metabolic rate | 60–70% | Organ function, circulation, cell maintenance at rest |
| Thermic effect of food | ~10% | Energy spent digesting; protein costs the most |
| Exercise activity | 5–15% | Deliberate training |
| Non-exercise activity (NEAT) | 15–30% | Fidgeting, walking, posture. Varies enormously between people |
How to Read Your Result
The activity multiplier is where the error is
The resting equation is reasonably tight. The multiplier is a five-point scale standing in for something continuous and highly individual. Moving one step up — 1.375 to 1.55 — adds about 300 kcal a day to the estimate for the man above, which is the entire difference between losing weight and not. Start one level lower than you think.
Why the 7,700 kcal per kilogram rule overstates loss
It assumes the deficit comes entirely from fat and that expenditure stays constant. Neither holds. As you lose weight, a lighter body burns less at rest, and NEAT tends to fall unconsciously — you move less without noticing. Real weight loss decelerates and plateaus; this is metabolic adaptation, not a failure of effort.
Treat the number as a starting hypothesis
The honest use of a TDEE figure is as a first estimate to test. Eat at that level consistently for two to three weeks, track weight, and adjust from what actually happens. Your measured response is far better data than any equation, because it accounts for everything the equation cannot see.
Limitations & Accuracy Notes
- Mifflin-St Jeor explained about 71% of the variance in the original study (R² = 0.71). Roughly a third of the variation between individuals is not captured, so your true resting expenditure may sit meaningfully above or below the prediction.
- The equation uses total body weight, not composition. Two people of the same height, weight and age but very different muscle mass get the same estimate. For lean, muscular individuals the Katch-McArdle equation, which uses fat-free mass, tends to fit better.
- It was derived from healthy adults aged 19–78. It is not validated for children, during pregnancy or breastfeeding, or in the presence of thyroid disorders and other metabolic conditions.
- Calorie counts on food labels carry their own error — commonly cited at around 20% for packaged foods — and portion estimation adds more. The intake side of the equation is often less accurate than the expenditure side.
- This is a general fitness estimate, not medical or dietary advice. Speak to a qualified professional before starting a significant calorie deficit, particularly with any existing health condition or history of disordered eating.
Frequently Asked Questions
What is TDEE and how is it calculated?
How many calories deficit is needed to lose 1 pound of fat?
What is the difference between BMR and TDEE?
Why is my TDEE different from a friend of the same weight?
Which activity level should I pick?
How accurate is the number?
What should I do if my weight is not changing?
How big a deficit should I use?
Is my health data stored?
References & Further Reading
- Mifflin MD, St Jeor ST, et al. (1990) — A new predictive equation for resting energy expenditure in healthy individuals, Am J Clin Nutr 51(2):241-7 — The source equation, derived from indirect calorimetry on 498 subjects
- Physical Activity Guidelines for Americans, 2nd edition (HHS) — US federal activity recommendations, useful for placing yourself on the activity scale