BMR vs TDEE: How Many Calories Do You Really Need?
If you have ever looked up how many calories you should eat, you have probably met two acronyms: BMR and TDEE. They sound similar, but they answer different questions, and mixing them up is one of the most common reasons calorie targets end up too low or too high.
BMR: calories at complete rest
Your basal metabolic rate (BMR) is the energy your body uses to stay alive if you did nothing all day: breathing, circulating blood, keeping warm and repairing cells. For many people it is the largest part of daily energy use.
A widely used formula is the Mifflin-St Jeor equation:
Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
TDEE: everything you burn in a day
Your total daily energy expenditure (TDEE) adds everything else to your BMR: walking around, working, exercising and even digesting food. It is usually estimated by multiplying BMR by an activity factor:
| Activity level | Multiply BMR by |
|---|---|
| Sedentary (desk job, little exercise) | 1.2 |
| Lightly active (exercise 1–3 days a week) | 1.375 |
| Moderately active (3–5 days a week) | 1.55 |
| Very active (6–7 days a week) | 1.725 |
A worked example
Take a 35-year-old woman who is 5 ft 5 in (165 cm) and weighs 154 lb (69.9 kg):
- BMR = 10 × 69.9 + 6.25 × 165.1 − 5 × 35 − 161 ≈ 1,394 calories
- With moderate exercise: TDEE ≈ 1,394 × 1.55 ≈ 2,161 calories
Her TDEE, not her BMR, is the number to plan around. Eating about 2,161 calories a day would roughly maintain her weight. Calculate your own with the BMR calculator and TDEE calculator.
Using TDEE to set a goal
- To maintain weight: eat around your TDEE.
- To lose weight gradually: a deficit of about 250 to 500 calories below TDEE is a common starting point. In the example above, that means roughly 1,660 to 1,910 calories a day.
- To gain weight or build muscle: a small surplus of about 250 calories, combined with strength training.
The calorie calculator does these steps for you, and the macro calculator splits the result into protein, carbs and fat.
Common mistakes
Eating at your BMR
Your BMR is what you burn lying still all day. Eating at or below it while being active creates a large deficit that is hard to sustain and may leave you short of nutrients.
Overestimating activity
Most people choose an activity level that is too high. If you are unsure, pick the lower option and adjust based on results.
Treating the number as exact
Formulas describe averages. Your real needs could be 10% higher or lower. Track your weight trend for two to three weeks, then adjust your intake by 100 to 200 calories if needed.
The bottom line
BMR tells you what your body needs to keep running; TDEE tells you what you actually burn. Plan your eating around TDEE, adjust slowly, and judge progress by trends over weeks rather than day-to-day changes. If you have a medical condition or are pregnant, talk to a doctor or registered dietitian for personal guidance.
This guide is for general education and planning. It is not personal financial, medical, tax or legal advice. See our disclaimer.
