Your TDEE is the total number of calories your body burns each day, accounting for everything from keeping your heart beating to your workouts. It is the foundation of any nutrition plan: eat below it to lose weight, eat at it to maintain, eat above it to gain. This calculator uses the Mifflin-St Jeor equation, the formula with the strongest scientific validation, to find your BMR (Basal Metabolic Rate) and then applies your activity level to get your TDEE. It then gives you precise calorie targets for every level of deficit or surplus, along with macronutrient recommendations.
Enter your details on the left and get your personalised daily calorie targets, macros, and time-to-goal estimate
TDEE stands for Total Daily Energy Expenditure. It is the total number of calories your body burns in a 24-hour period, accounting for your resting metabolism (keeping your organs running, maintaining body temperature, breathing) plus all physical activity including exercise, daily movement, and even the energy cost of digesting food. Understanding your TDEE is the starting point for any evidence-based nutrition approach, because your calorie intake relative to your TDEE determines whether you lose, maintain, or gain weight.
Your TDEE is not fixed. It changes as your weight changes (heavier people burn more calories), as you age (BMR declines by roughly 1-2% per decade after 30), and in response to significant changes in activity level. Recalculate your TDEE every 5 to 10 kg of weight change, or if your activity level changes significantly.
Your BMR (Basal Metabolic Rate) is the number of calories your body needs at complete rest, in a fasted state, in a thermoneutral environment, to sustain basic physiological functions. It represents approximately 60 to 75% of your total daily calorie burn. BMR is calculated from your height, weight, age, and sex using a validated equation.
Your TDEE is BMR multiplied by an activity factor. A sedentary person with a BMR of 1,600 calories has a TDEE of approximately 1,920 (1,600 times 1.2). A very active person with the same BMR has a TDEE of 2,760 (1,600 times 1.725). The activity multiplier is the most variable part of the calculation and the one most people get wrong by overestimating their activity level.
This calculator uses the Mifflin-St Jeor equation, published in 1990, which has consistently outperformed other formulas in studies comparing predicted BMR to measured resting metabolic rate. The formula is:
For men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5
For women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161
The revised Harris-Benedict equation (1984) is also shown for comparison. It tends to produce estimates 5 to 10% higher than Mifflin-St Jeor and has been found to slightly overpredict BMR for sedentary populations. The Katch-McArdle formula, shown when you enter body fat percentage, calculates BMR from lean body mass rather than total weight, and is the most accurate option for individuals who know their body composition.
The activity multiplier is where most people introduce the largest error into their TDEE estimate. The most common mistake is overstating activity level, which leads to overestimating calorie needs and unintentionally eating above maintenance.
Sedentary (1.2x) applies to people with desk jobs who do not exercise and do minimal walking. Lightly active (1.375x) is appropriate for someone who walks regularly or does light exercise one to three times per week. Moderately active (1.55x) fits most people who exercise consistently three to five days per week with genuine effort. Very active (1.725x) applies to people training hard six to seven days per week, such as competitive athletes in preparation. Extremely active (1.9x) is reserved for people with physically demanding jobs such as construction or farming who also train regularly, or those doing twice-daily training sessions.
If weight loss is your goal and you have been eating what you believe is a deficit but not losing weight, the most likely explanation is that your TDEE is lower than estimated, either because of a lower activity multiplier than you have selected or because your metabolism has adapted to a chronic deficit. Try the next multiplier down.
One kilogram of body fat contains approximately 7,700 calories of stored energy. This means a consistent deficit of 500 calories per day produces a theoretical weight loss of approximately 0.5 kg per week (500 times 7 days divided by 7,700). A 1,000-calorie daily deficit produces approximately 1 kg per week of loss in theory.
In practice, several factors modify this. When you first reduce calories, some early weight loss is water and glycogen rather than fat, making the first week or two look faster than the true fat loss rate. Over longer periods, the body adapts to caloric restriction through metabolic adaptation (lowering BMR slightly) and spontaneous reductions in non-exercise activity, which reduces the effective deficit. This is why weight loss often slows after the first few weeks even if calorie intake stays the same.
A deficit of 500 calories per day is generally considered the sweet spot: meaningful fat loss without the significant muscle loss, hormonal disruption, and fatigue associated with very aggressive deficits. Deficits below 1,200 calories per day for women and 1,500 per day for men are not recommended without medical supervision.
Calories determine whether you lose or gain weight. Macronutrients determine the composition of that weight change and affect how you feel and function during the process.
Protein is the most important macronutrient during a calorie deficit. Consuming 1.6 to 2.2 grams of protein per kilogram of body weight per day substantially reduces muscle loss during caloric restriction, keeps you fuller for longer (protein has the highest satiety per calorie), and has a higher thermic effect (the body burns more calories digesting protein than carbohydrates or fat). For most people in a deficit, aiming for 2 grams per kilogram of body weight is a practical and effective target.
Dietary fat should not drop below approximately 0.7 to 0.8 grams per kilogram of body weight per day, as fat is required for hormone production, fat-soluble vitamin absorption, and joint health. Below this threshold, hormonal disruption becomes a real risk, particularly for women.
Carbohydrates fill the remaining calorie budget after protein and fat targets are met. They are the primary fuel source for the brain and for intense exercise. Reducing carbohydrates too aggressively often leads to fatigue, reduced exercise performance, and difficulty maintaining training volume.
TDEE calculators are estimates, not measurements. Most research suggests that predictive equations like Mifflin-St Jeor come within 10 to 15% of actual measured metabolic rate for most people. This means your calculated TDEE might be as much as 200 to 300 calories per day off in either direction. The best approach is to use the calculated TDEE as a starting point, track your weight over 2 to 3 weeks at that intake, and adjust based on actual results.
The most common reasons are: calorie tracking errors (most people underestimate food intake by 20 to 40%), overestimated activity level in the TDEE calculation, metabolic adaptation to a chronic deficit, or water retention masking fat loss on the scale. If you have been consistent at a deficit for 3 to 4 weeks without scale movement, try reducing intake by a further 100 to 200 calories per day or increasing activity, and wait another 2 to 3 weeks before adjusting again.
If you used the TDEE calculator with an activity multiplier that already includes your exercise (for example, moderately active because you work out four times a week), you should not eat back exercise calories, as they are already factored into your TDEE. If you used sedentary as your baseline and track exercise separately, you may choose to eat back a portion of those calories. A conservative approach is to eat back 50% of estimated exercise calories to account for the typical overestimation of calorie burn from exercise trackers and gym equipment.
General guidelines suggest that women should not regularly consume fewer than 1,200 calories per day and men should not regularly consume fewer than 1,500 calories per day without medical supervision. Below these levels, it becomes very difficult to meet minimum nutrient needs, and the risk of lean muscle loss, nutrient deficiencies, fatigue, and hormonal disruption increases substantially. Aggressive deficits can also trigger metabolic adaptation that makes subsequent weight management harder.
Yes. As you lose weight, your body burns fewer calories at rest (because there is less mass to sustain) and during activity (because you are moving less body weight). For every kilogram of weight lost, TDEE typically decreases by approximately 15 to 20 calories per day, though the exact amount depends on how much of the lost weight was muscle versus fat. Recalculate your TDEE every 5 to 10 kg to keep your targets accurate.
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