TDEE calculator

How TDEE is calculated

The calculator works in two steps. First it estimates your basal metabolic rate (BMR), the calories your body uses at rest, from your sex, age, height and weight. Then it multiplies that by an activity factor to get your total daily energy expenditure:

• Mifflin-St Jeor (the default): BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age, then + 5 for men or − 161 for women.
• Harris-Benedict, revised in 1984: men 88.362 + 13.397 × kg + 4.799 × cm − 5.677 × age; women 447.593 + 9.247 × kg + 3.098 × cm − 4.330 × age.
• Katch-McArdle: BMR = 370 + 21.6 × lean body mass in kg, where lean mass is your weight minus your body fat.
• TDEE = BMR × activity factor.

Worked examples

• Lightly active woman: 35 years old, 5 ft 7 in (170 cm) and 160 lb (72.6 kg). Mifflin-St Jeor gives a BMR of 1,453 calories. Light exercise is a factor of 1.375, so her TDEE is about 2,000 calories a day, likely somewhere between 1,800 and 2,200. The revised Harris-Benedict equation would put her BMR at 1,494.
• Desk-bound man: 45 years old, 5 ft 10 in and 200 lb, with little exercise. His BMR is about 1,798 and his TDEE 2,160 calories a day (× 1.2). Adding three or four brisk workouts a week would move him to the moderately active level, about 2,790.

The activity levels

The example column is for the 35-year-old woman above. Moving from the lowest level to the highest nearly doubles what she can eat without gaining weight.

Which formula should I use?

Use Mifflin-St Jeor unless you have a reason not to. A 2005 systematic review for the American Dietetic Association found it the most reliable of the common equations, within 10% of measured resting energy for more people, lean or obese, than the others. The original Harris-Benedict equation dates from 1919, and the version here was refit to new data in 1984. It usually gives a slightly higher number than Mifflin-St Jeor, and in that review it landed within 10% of measured values less often. Katch-McArdle is worth choosing if you know your body fat from a scan, because it works from lean mass, which burns most of the energy, instead of sex and age. That matters most for very muscular people, whose needs the other formulas tend to underestimate.

Turning TDEE into a goal

To lose weight you eat less than your TDEE; to gain, more. The old rule of thumb says a pound of fat holds about 3,500 calories, so 500 fewer a day loses about a pound a week. That holds for the first few weeks, but research from the NIH shows that weight loss then slows as your body gets smaller and burns less. The NIH’s Body Weight Planner models that slowdown, and so does our calorie deficit calculator, which shows a goal date. About 1 to 2 lb a week is the pace the CDC describes as gradual and steady.

Next, split your calories into protein, carbs and fat with the macro calculator, or see how much protein you need with the protein calculator. The BMR calculator puts all three formulas side by side.

Sources

• Mifflin MD, St Jeor ST et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990.
• Roza AM, Shizgal HM. The Harris Benedict equation reevaluated. American Journal of Clinical Nutrition, 1984.
• Frankenfield D et al. Comparison of predictive equations for resting metabolic rate. Journal of the American Dietetic Association, 2005.
• Jensen MD et al. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults. Circulation, 2014.
• Hall KD et al. Quantification of the effect of energy imbalance on bodyweight. The Lancet, 2011.

This calculator gives an estimate for healthy adults. It isn’t medical advice. If you have a health condition, take medication that affects your weight, or are pregnant or breastfeeding, talk to your doctor or a registered dietitian before changing how much you eat.