TDEE Calculator: Free Online BMR and Calorie Calculator
Updated October 2026
TDEE (Total Daily Energy Expenditure) is the number of calories your body burns in a day: at rest, digesting food, moving around and exercising. Eat at your TDEE and your weight stays stable; eat below it and you lose weight. This free TDEE calculator estimates it from your sex, age, height, weight and activity level, and runs entirely in your browser, so nothing you type is sent anywhere.
These are estimates for healthy adults aged 18 to 80, not medical advice. Pregnancy, breastfeeding, illness and some medications change energy needs; in those cases follow your doctor’s target.
What Is TDEE?
TDEE adds up everything your body spends energy on in 24 hours. The largest part for most people is the basal metabolic rate (BMR): the energy your organs use at complete rest. On top of that come digesting food, deliberate exercise, and everyday movement such as walking, standing and climbing stairs.
BMR changes slowly with body size. Movement changes with how you live, so two people of the same height and weight can have TDEEs hundreds of calories apart.
How the TDEE Calculator Works
The calculator estimates your BMR with the Mifflin-St Jeor equation, then multiplies it by an activity factor. Imperial entries are converted to centimetres and kilograms first.
- Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5
- Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161
Mifflin and colleagues published the equation in the American Journal of Clinical Nutrition in 1990, from 498 healthy adults (247 women and 251 men, aged 19 to 78) whose resting energy expenditure was measured by indirect calorimetry. In that study the older Harris-Benedict equations from 1919 overestimated measured resting expenditure by 5%.
The default numbers above are a worked example: a 30-year-old woman, 165 cm tall, weighing 65 kg. Her BMR is 650 + 1,031.25 - 150 - 161 = 1,370 calories. At a moderate activity level her TDEE is 1,370 x 1.55 = 2,124 calories a day.
Activity Levels Explained
The activity factor scales your BMR up to cover everything you do beyond resting. Pick the level that matches a typical week, not your best one.
- Sedentary, x 1.2: desk job, little or no exercise.
- Lightly active, x 1.375: light exercise 1 to 3 days a week.
- Moderately active, x 1.55: moderate exercise 3 to 5 days a week.
- Very active, x 1.725: hard exercise 6 to 7 days a week.
- Extra active, x 1.9: hard daily training plus a physically demanding job.
These five multipliers are the standard factors used by most TDEE calculators. They are rules of thumb, not the result of one study. For comparison, the FAO/WHO/UNU expert report on human energy requirements (2004) puts sedentary or light lifestyles at 1.40 to 1.69 times BMR, active lifestyles at 1.70 to 1.99 and vigorous lifestyles at 2.00 to 2.40.
How to Use Your TDEE for a Calorie Deficit
Eating below your TDEE creates a calorie deficit. The calculator’s loss target is your TDEE minus 500 calories a day, the conventional figure for losing about 0.5 kg (1 lb) a week, based on the rule of thumb that a pound of body fat stores about 3,500 calories. Its gain target adds 250 calories a day, a modest surplus that limits fat gain.
Treat the target as a starting point. Hall and colleagues showed in The Lancet in 2011 that weight responds slowly to a change in intake, with a half-time of about a year, because expenditure falls as weight falls. A fixed deficit therefore loses less over time than the 3,500-calorie arithmetic predicts.
Log what you eat and track your weekly average weight for two to three weeks. If weight is falling faster or slower than planned, change your intake by 100 to 200 calories a day and reassess. The calorie deficit guide covers sizing and tracking a deficit week to week.
How Accurate Is a TDEE Calculator?
Every TDEE calculator gives an estimate, not a measurement. A 2005 systematic review by Frankenfield and colleagues found Mifflin-St Jeor the most reliable of the four equations most used in practice: it came within 10% of measured resting metabolic rate in more people than the others, with the narrowest error range. It also warned that errors in individuals are still noteworthy, and that older adults and some ethnic groups were underrepresented.
The equation also ignores body composition, so it can underestimate a very muscular person’s needs, and the activity factor is your own judgement. A 10% error on a TDEE of 2,124 calories is about 210 calories a day, close to half of a 500-calorie deficit.
Frequently Asked Questions
What does TDEE stand for?
TDEE stands for Total Daily Energy Expenditure: the total number of calories your body burns in 24 hours, including rest, digestion, daily movement and exercise.
What is the difference between BMR and TDEE?
BMR (basal metabolic rate) is what your body burns at complete rest. TDEE is BMR multiplied by an activity factor, so it also covers digestion, movement and exercise. TDEE is the number to eat at to keep your weight stable.
Is this TDEE calculator free?
Yes. It is free, needs no account and runs entirely in your browser. Nothing you enter is sent to VitaCal or anyone else.
How many calories should I eat to lose weight?
Start about 500 calories a day below your TDEE, the conventional figure for losing about 0.5 kg (1 lb) a week. After two to three weeks, check your weekly average weight and adjust by 100 to 200 calories a day if the rate is off.
Which formula does this TDEE calculator use?
The Mifflin-St Jeor equation (Mifflin et al., American Journal of Clinical Nutrition, 1990) for BMR, multiplied by the standard activity factors of 1.2, 1.375, 1.55, 1.725 or 1.9.
How often should I recalculate my TDEE?
Recalculate after every few kilograms of weight change or a change in activity. A smaller body burns fewer calories, so the same intake becomes a smaller deficit as you lose weight.
Sources
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990; 51(2): 241-247.
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association, 2005; 105(5): 775-789.
- Hall KD, Sacks G, Chandramohan D, et al. Quantification of the effect of energy imbalance on bodyweight. The Lancet, 2011; 378(9793): 826-837.
- FAO, WHO, UNU. Human energy requirements: report of a joint FAO/WHO/UNU expert consultation. Rome, 2004.
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