How to calculate your TDEE (and what to do with the number)
Two steps, one formula, and a simple check that tells you whether the number is right for you.
How do you calculate TDEE?
TDEE stands for total daily energy expenditure: the calories you burn in a full day, including digestion, daily movement and exercise. You calculate it in two steps. First, estimate your basal metabolic rate (BMR) with the Mifflin-St Jeor equation. Second, multiply that BMR by an activity factor between 1.2 and 1.9.
The Mifflin-St Jeor equation was published in 1990 and is still the standard formula for healthy adults. A later systematic review compared the common predictive equations and concluded that Mifflin-St Jeor was the most reliable of the group in both nonobese and obese adults. The two versions are:
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161
Use kilograms and centimeters. If you think in pounds and inches, divide pounds by 2.2 to get kilograms and multiply inches by 2.54 to get centimeters before you start.
Step 1: Estimate your BMR with Mifflin-St Jeor
Take a 35-year-old man who weighs 75 kg (165 lb) and is 178 cm (5 ft 10 in) tall. Work through the equation one term at a time so you can see where each number comes from.
- 10 × 75 kg = 750
- 6.25 × 178 cm = 1,112.5
- 5 × 35 years = 175
- BMR = 750 + 1,112.5 − 175 + 5 = 1,692.5 kcal per day, which rounds to 1,693
A woman with the same weight, height and age would use −161 instead of +5: 750 + 1,112.5 − 175 − 161 = 1,526.5, or about 1,527 kcal per day. BMR is what you would burn lying still all day. Almost nobody eats at BMR; it is only the base for the next step.
Step 2: Multiply by your activity level
The activity multiplier turns BMR into TDEE. Pick the row that matches a typical week, including your job, not just your workouts.
| Activity level | Multiplier | What it looks like | TDEE for our example (BMR 1,693) |
|---|---|---|---|
| Sedentary | 1.2 | Desk job, little or no exercise | 1,693 × 1.2 = 2,032 kcal |
| Light | 1.375 | Exercise 1 to 3 days a week | 1,693 × 1.375 = 2,328 kcal |
| Moderate | 1.55 | Exercise 3 to 5 days a week | 1,693 × 1.55 = 2,624 kcal |
| Active | 1.725 | Hard exercise 6 to 7 days a week | 1,693 × 1.725 = 2,920 kcal |
| Very active | 1.9 | Physical job plus daily training | 1,693 × 1.9 = 3,217 kcal |
Our example trains four days a week and sits at a desk the rest of the time, so moderate fits: 1,693 × 1.55 = about 2,620 kcal per day. That is his starting TDEE.
If you are torn between two rows, choose the lower one. People tend to overstate how much they move. In one well-known study, participants over-reported their physical activity by 51% on average when their reports were compared with measurements.
Why do TDEE calculators give different numbers?
Type the same stats into five calculators and you will get five answers, sometimes hundreds of calories apart. There are four common reasons.
- Different BMR equations. Some sites use Harris-Benedict or a formula that needs body-fat percentage. Each one produces a slightly different base.
- Different multipliers. One site calls 1.55 "moderate" while another calls it "active", or uses 1.4, 1.6 and 1.8 instead of the classic ladder.
- Exercise counted twice. Some calculators add workout calories on top of an activity multiplier that already includes them.
- Rounding. Rounding BMR, the multiplier and the final result in different places shifts the answer by 20 to 50 kcal.
None of these calculators measures you. The equation predicts the average person of your size, sex and age, and you may sit above or below that average. Treat every result as a starting estimate with an error band of a few hundred calories, then let real data correct it.
How to adjust TDEE after 2 to 3 weeks of tracking
Your true TDEE shows up on the scale. If you eat a known number of calories and your weight holds, that intake is your TDEE. If you lose or gain, the change tells you how far off the estimate was.
- Log everything you eat for 14 to 21 days at a steady intake. Photo logging in Cal.AI keeps this quick; the result screen shows each item and the meal total, and Fix Results lets you correct a portion before you save.
- Weigh yourself every morning under the same conditions and average each week. Daily readings swing with water and salt; weekly averages do not.
- Compare the first weekly average with the last one.
- Convert the change to calories using the rule of thumb of about 7,700 kcal per kg (3,500 kcal per lb) of body fat.
Say our example ate an average of 2,300 kcal per day and his weekly average dropped by 0.6 kg (1.3 lb) over three weeks. That is 0.6 × 7,700 = 4,620 kcal of deficit across 21 days, or 4,620 ÷ 21 = 220 kcal per day. His measured TDEE is therefore about 2,300 + 220 = 2,520 kcal, roughly 100 kcal below the formula. He should plan around 2,520, not 2,620.
This check works well over a few weeks. Over months, expenditure falls as body weight falls, which is why the 3,500-kcal rule overestimates long-term loss. Re-run the formula, or repeat the three-week check, every time you lose or gain around 5 kg (11 lb). The NIDDK Body Weight Planner models this slowdown if you want a longer projection.
If you track activity with a watch, the app can read active energy from Apple Health, and you choose whether those burned calories are added to the daily budget. If you already picked an activity multiplier that includes your workouts, leave that off to avoid counting exercise twice.
Common mistakes
- Using pounds in a formula that expects kilograms. The answer comes out far too high.
- Picking "active" because you train hard three times a week while sitting the other 160 hours. Count the whole week.
- Adding tracker-reported exercise calories on top of a multiplier that already includes exercise.
- Judging the estimate from a single week of scale readings instead of a two- to three-week average.
- Never recalculating. A TDEE from 10 kg ago is the wrong number today.
Frequently asked questions
Is TDEE the same as maintenance calories?
Yes, in practice. TDEE is the number of calories you burn in a day, and maintenance calories are the intake that keeps your weight stable. If the estimate is right, they match. If you eat at your estimated TDEE and still lose or gain weight, your real maintenance is different and you should adjust using the tracking method in this guide.
Should I use my current weight or my goal weight to calculate TDEE?
Use your current weight. TDEE describes what your body burns today, and the equation needs today's weight to do that. As you lose or gain, recalculate every 5 kg (11 lb) or so. Goal weight is sometimes used for protein targets in people with a lot of weight to lose, but not for TDEE.
How accurate is the Mifflin-St Jeor equation?
It is the most reliable of the common prediction equations according to a systematic review of the published formulas, but it still predicts an average, not you. Individual resting metabolic rates vary around that average, so treat the result as a starting point and confirm it with two to three weeks of logged intake and weekly weight averages.
Does TDEE change when I lose weight?
Yes. A smaller body burns fewer calories, so TDEE drops as weight drops, and studies show expenditure often falls a little more than the new body size alone would predict. That is why a calorie target that worked at the start of a diet stops working months later. Recalculate as you go rather than keeping one fixed number.
Sources
- Mifflin MD, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247. PubMed
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005;105(5):775-789. PubMed
- Lichtman SW, et al. Discrepancy between self-reported and actual caloric intake and exercise in obese subjects. N Engl J Med. 1992;327(27):1893-1898. PubMed
- Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837. PubMed
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