What TDEE and BMR mean
Your TDEE (Total Daily Energy Expenditure) is the number of calories your body burns across a full day — everything from breathing and digesting to walking, working, and training. It’s the number that actually matters for managing your weight, because it sets the break-even point between what you eat and what you burn.
Your BMR (Basal Metabolic Rate) is one slice of that total. It’s the energy you’d burn lying in bed all day without moving a muscle — the minimum needed to keep your heart, brain, kidneys, and everything else running. For most people, BMR accounts for roughly 60% to 70% of total daily burn.
The link between them is simple: start with BMR, then multiply by an activity factor to reach TDEE. Everything runs in your browser — your numbers are never stored or uploaded.
How to use the calculator
- Sex: pick male or female. The formula adjusts because, at the same weight and height, men tend to carry more muscle.
- Age: in years. Metabolism drifts down slowly as you get older.
- Weight in kilograms and height in centimeters.
- Activity level: choose the most honest option. Most people overestimate how active they are — when you’re torn between two levels, pick the lower one.
The calculator returns your TDEE, your BMR, and three calorie targets: maintain, lose, and gain.
The Mifflin-St Jeor formula
We use the Mifflin-St Jeor equation, published in 1990 and widely regarded as the most accurate estimate of resting metabolism in healthy adults — more reliable than the older Harris-Benedict equation.
- Men:
BMR = 10 × weight + 6.25 × height − 5 × age + 5 - Women:
BMR = 10 × weight + 6.25 × height − 5 × age − 161
Then: TDEE = BMR × activity factor.
Worked example
A 30-year-old man weighing 80 kg at 180 cm with moderate activity:
- BMR = 10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 800 + 1125 − 150 + 5 = 1780 kcal
- TDEE = 1780 × 1.55 = 2759 kcal/day
To hold his weight he’d eat about 2759 kcal. To lose, subtract 500 for roughly 2259 kcal. To gain, add 500 for roughly 3259 kcal.
Activity factor table
| Level | Description | Factor |
|---|---|---|
| Sedentary | Little or no exercise, desk job | 1.2 |
| Light | Light exercise 1-3 days per week | 1.375 |
| Moderate | Moderate exercise 3-5 days per week | 1.55 |
| Active | Hard exercise 6-7 days per week | 1.725 |
| Very active | Physical job or two training sessions a day | 1.9 |
The 500-calorie deficit and surplus
One kilogram of body fat stores roughly 7700 kcal. A daily deficit of 500 kcal adds up to about 3500 kcal a week, or close to 0.45 kg of weekly loss. A 500-kcal surplus does the reverse for controlled weight gain.
Treat it as a guide, not a promise. Your body adapts, holds water, and fluctuates day to day. A swing of 250 to 500 kcal is usually more sustainable than an aggressive cut.
Disclaimer: this calculator gives an informational estimate for educational purposes. It is not medical or nutritional advice. Talk to a healthcare professional before starting a diet, especially if you have any medical condition.
Frequently asked questions
What’s the difference between TDEE and BMR?
BMR is what you burn at complete rest; TDEE adds your daily movement and exercise on top. TDEE is always the larger number. Plan your eating around TDEE, not BMR — eating only your BMR would be a very steep deficit.
How often should I recalculate?
Recalculate whenever your weight shifts noticeably, around 3 to 5 kg. As you lose weight your body needs fewer calories, so a deficit that once worked stops working. Rerunning the numbers keeps your targets matched to your current size.
I’m in a deficit but not losing weight — why?
Almost always one of two reasons: underestimating what you eat (oils, drinks, snacks) or overestimating your activity when picking the factor. Weighing your food for a few days and dropping one activity level usually reveals the gap. Short-term water and hormones play a role too.
What about macronutrients?
Once you have your calorie target, you can split it across protein, fat, and carbohydrates. A common starting point is enough protein to protect muscle, but the ideal split varies by person and goal. This tool calculates calories — it doesn’t prescribe macros.