TDEE Calculator

What TDEE is, and why the number you guess is usually too high

TDEE is total daily energy expenditure: every calorie your body spends in 24 hours. Four things make it up. Your basal metabolic rate, the cost of simply being alive, is the largest slice and usually lands somewhere around 60 to 70 percent of the total. The thermic effect of food, the energy used to digest what you eat, takes roughly a tenth. Deliberate exercise is the part everyone thinks about and, for most people who are not athletes, the smallest. The remainder is everything else you do while awake: walking to the shops, standing, carrying, fidgeting. That last category varies enormously between two people of the same size, and it is the main reason two colleagues with identical height, weight and age can need noticeably different amounts of food.

The arithmetic is simple. This page estimates your BMR with the Mifflin-St Jeor equation, then multiplies it by an activity factor between 1.2 and 1.9. The arithmetic is not where people go wrong. The factor is. Choosing moderately active when lightly active is honest adds several hundred calories to the answer, which is enough to turn an intended deficit into maintenance and leave you wondering why nothing is happening. An hour in the gym is about four percent of your day, so training three times a week moves the needle far less than the word active suggests.

Which activity level fits you, and which target to use

Pick the row that describes an ordinary week, not your best week. If two rows both sound plausible, take the lower one: it is far easier to notice that you are losing weight faster than planned and add food back than it is to work out why a deficit that was never really a deficit is not working.

Then choose which of the three figures on screen you are actually going to eat:

• Maintenance, the headline TDEE: holding your weight while you train, recovering from a long diet, or simply learning what a normal day of food looks like for you.
• The fat loss target: losing body fat while keeping as much muscle as you can. A deficit of 300 to 500 kcal is the range most coaches and dietitians start people on, and the card on this page uses 500.
• The muscle gain target: gaining size alongside resistance training. A surplus of 200 to 500 kcal is the usual starting point, and the card uses 300.
• The macro split: protein, carbohydrate and fat in grams. Use it when your app asks for macro goals rather than one calorie number. Protein first, since it is the figure that most affects how much muscle survives a diet.

How to find your maintenance calories

1. Choose your units. The calculator opens in imperial, with feet, inches and pounds. Switch to metric for centimetres and kilograms; the result is identical either way.
2. Enter sex, age, height and weight. The equation was built around male and female coefficients, so choose the one that matches your physiology rather than any other consideration.
3. Pick an activity level from the five cards, using the table above and erring low.
4. Read the large figure. That is your estimated maintenance intake in calories per day.
5. Look at the bar underneath. The blue segment is your resting burn, the orange segment is everything the activity factor added, and the two dashed lines mark the fat loss and muscle gain targets.

How to correct the estimate after two weeks

A calculator cannot know your individual metabolism or how much you move without noticing. What it gives you is a starting point worth testing, and two weeks of honest tracking beats any equation.

1. Eat the target consistently for fourteen days. Weigh your food rather than guessing portions for at least the first week, since underestimating intake is the single most common error in self-reported food diaries.
2. Weigh yourself several mornings a week under the same conditions, after the toilet and before breakfast.
3. Compare the average of week two against the average of week one. Never compare single days: a salty dinner or a missed bowel movement moves the scale by more than a week of fat loss does.
4. If you wanted to lose and the average has not moved, subtract 100 to 200 kcal and run another two weeks. If you are losing more than about one percent of body weight a week, add some back.
5. Recalculate as your weight changes. A lighter body burns less, so a target that worked at the start will eventually become your new maintenance. Every four to six kilos, or roughly every ten pounds, is a sensible interval.

Getting the number into the app you actually use

• Calorie tracking apps: most let you override the goal the app suggested. Look for a custom or manual goal setting and type the figure from this page in, rather than letting the app work out its own target from a weekly weight loss rate.
• Apps that want macros: enter the protein, carbohydrate and fat grams from the split on this page. Some apps accept percentages instead, which are shown next to each value.
• Keeping a record: the figures live only on screen, so screenshot the result or write the four numbers down before you close the tab. Nothing is saved between visits.
• Sharing with a coach or dietitian: send the inputs, not just the answer. Sex, age, height, weight and the activity level you chose are what let someone else judge whether the estimate is sensible.

Why other calculators, apps and watches disagree

• Mifflin-St Jeor, used here, was published in 1990 and fitted to a large sample of healthy adults. It is the equation most dietetic practice reaches for by default when body composition is unknown.
• Harris-Benedict, from 1919 and revised in 1984, is the one many older calculators still run. It tends to return a slightly higher resting figure than Mifflin-St Jeor for the same person, which is enough to explain a difference of a hundred calories or so between two sites.
• Katch-McArdle ignores height and sex and works from lean body mass instead, so it needs a body fat percentage. For a lean, muscular person it is usually the better fit; for everyone else it inherits whatever error came with the body fat estimate.
• Fitness trackers and smartwatches do not use an equation alone. They estimate active energy from heart rate and motion and add a resting estimate of their own, then report a rolling daily total that moves as you move. Two devices on the same wrist can differ by a few hundred calories, and a treadmill display is a third answer again.
• Calorie apps such as MyFitnessPal often take a different route entirely: you tell them how fast you want to lose weight, and they work backwards to a goal, then credit logged workouts on top of it. That is a coherent system, but it is not the same system as a fixed TDEE that already includes your training. Picking one and staying with it matters more than which one you pick.

Limits worth knowing before you act on the number

This is a general information tool, not medical advice, and it cannot account for pregnancy, breastfeeding, thyroid or metabolic conditions, medication that affects appetite or weight, a history of disordered eating, or growth in children and teenagers. Talk to a doctor or a registered dietitian before making significant changes to what you eat, and especially before going below roughly 1,200 kcal a day, a level at which meeting basic nutrient needs becomes difficult.

Two more honest limits. The equation was fitted to group averages, so individual results scatter around it, commonly by about ten percent in either direction; your own tracked results always outrank the estimate. And the common rule that 3,500 kcal equals a pound of fat describes the first few weeks reasonably well but overstates what happens over months, because a lighter body burns less and long diets tend to quietly reduce how much you move.