TDEE Calculator

How Accurate Is a TDEE Calculator

A TDEE calculator that uses the Mifflin-St Jeor equation lands within 10% of your measured resting burn more often than one built on any other common equation. A 2005 systematic review in the Journal of the American Dietetic Association compared the four equations most used in clinical practice. Mifflin-St Jeor predicted resting metabolic rate within 10% of the measured value in more people, lean and obese, than any other. It also had the narrowest error range.

The older Harris-Benedict equation from 1919 overestimated measured resting burn by about 5% in the 498 adults Mifflin and St Jeor tested in 1990. That 5% gap is why this calculator uses Mifflin-St Jeor. On the worked example below, 5% of a 2,660-calorie TDEE is about 130 calories a day.

The review also flagged a limit worth knowing. Older adults and US ethnic minority groups were underrepresented in the studies that built and checked these equations, so the equations have been checked less for them. A measured test (indirect calorimetry) is the only way to get your own number.

How This TDEE Calculator Works

This TDEE calculator multiplies your resting burn by a physical activity level (PAL) factor. Your basal metabolic rate (BMR) is the calories your body uses at rest. TDEE adds everything you burn moving, working and exercising on top of that.

1. Resting burn. Women: 10 x weight in kg + 6.25 x height in cm - 5 x age - 161. Men: the same, plus 5 instead of minus 161.
2. Activity factor. The Food and Agriculture Organization (FAO), World Health Organization (WHO) and United Nations University (UNU) 2004 report on human energy requirements groups lifestyles into three bands: sedentary or light activity (1.40 to 1.69), active or moderately active (1.70 to 1.99), and vigorous (2.00 to 2.40).
3. Your TDEE. The calculator uses the middle of your band for the headline number and shows the low and high ends as your range.
4. Weight-loss targets. The 2013 American Heart Association, American College of Cardiology and The Obesity Society (AHA/ACC/TOS) obesity guideline prescribes an energy deficit of 500 or 750 calories a day, so the calculator subtracts both.

Pounds and inches are converted to kilograms and centimeters first. The math runs in your browser, and your inputs are not saved unless you choose to email yourself the results.

A Worked TDEE Example

A 40-year-old woman who is 5 feet 5 inches (165 cm) and weighs 170 pounds (77 kg) has a resting burn of about 1,440 calories a day. That number comes from 771 + 1,032 - 200 - 161.

If her usual month is active or moderately active, her factor is 1.845, the middle of 1.70 to 1.99. Her TDEE is about 2,660 calories a day, with a range of 2,450 to 2,870. If she is sedentary instead, the same body burns about 2,230, which shows how much the activity choice moves the answer.

Her weight-loss targets at the active level are about 2,160 calories a day with a 500-calorie deficit and 1,910 with a 750-calorie deficit. Both sit above the 1,200 to 1,500 calories a day the 2013 guideline usually prescribes for women.

How to Use Your TDEE to Lose Weight

Treat your 500-calorie target as a number to test for two to three weeks, then adjust it from what your scale does. The equation only sees your age, sex, height and weight, so two people with the same four numbers get the same answer even when their real burn differs.

1. Pick the 500-calorie target unless a clinician has set a different one.
2. Weigh yourself at the same time of day, three or more mornings a week, and watch the weekly average.
3. If the average has not moved after three weeks of accurate logging, lower intake by 100 to 200 calories a day.
4. Run the calculator again every 10 pounds or so, because a smaller body burns less.

Weight loss slows partly because the TDEE you started with no longer applies, which is covered in our weight loss plateau guide. For the woman in the worked example, each 10 pounds lost lowers her TDEE by about 85 calories a day. The NIDDK Body Weight Planner from the National Institute of Diabetes and Digestive and Kidney Diseases projects your weight over a timeframe you set, from the same kind of inputs.

When the TDEE Calculator Is Wrong for You

The TDEE calculator does not fit pregnancy, breastfeeding, anyone under 18, or anyone with a history of an eating disorder. Each of these needs a calorie plan from a clinician or registered dietitian.

It also reads high or low in a few common cases. Very muscular people burn more at rest than the equation expects, because fat-free mass was the best single predictor of resting burn in the 1990 Mifflin study. The vigorous band stops at 2.40 because the FAO, WHO and UNU report found higher levels hard to keep up for long. A short block of heavier training can burn more than the calculator shows.

If the calculator gives a weight-loss target below 1,200 calories a day for a woman or 1,500 for a man, it flags the number. Those are the levels the 2013 guideline usually starts from, so plan anything lower with a clinician. If a month of careful tracking brings no change, check for a medical cause with our guide to why you are not losing weight. The weight management hub links every other weight guide on the site.

TDEE vs BMR

BMR is what you burn lying still, and TDEE is BMR plus everything you do in a day. For most adults TDEE is 1.4 to 2.4 times BMR, which is the full span of the FAO, WHO and UNU activity bands.

The difference matters when you set a target. For the woman in the worked example, eating at her BMR of 1,440 instead of her TDEE of 2,660 is a 1,220-calorie deficit, well over the 500 to 750 the 2013 guideline uses. Set your target from TDEE, then pair it with protein and resistance training from our evidence-based weight loss tips.