Basics
What Is TDEE? Total Daily Energy Expenditure Explained
TDEE, or total daily energy expenditure, is the total number of calories your body uses in a day: your basal metabolic rate (BMR) plus the energy used to digest food and to move, from workouts to walking around. Eating about your TDEE maintains your weight, eating less leads to weight loss over time, and the most common way to estimate it is to multiply your BMR by an activity factor.
What TDEE means
Your body never stops using energy. Even asleep, it is breathing, pumping blood, keeping you warm and repairing tissue. During the day you add digestion, standing, walking, typing, cooking and any exercise you do. Total daily energy expenditure is the sum of all of it, measured in calories (kilocalories, strictly).
TDEE matters because it is the number your eating is compared against. In plain terms:
- Eat about your TDEE and your weight stays roughly stable. That is why TDEE is often called your maintenance calories.
- Eat consistently below it and you are in a calorie deficit, which leads to weight loss over time.
- Eat consistently above it and you are in a surplus, which leads to weight gain.
Every sensible calorie target starts here. If you want to turn your TDEE into a daily goal, see how many calories you should eat a day.
The four parts of TDEE
TDEE is usually broken into four components. You do not need to calculate each one, but knowing them explains why your number is what it is and why it changes.
| Component | What it covers | How much it varies |
|---|---|---|
| BMR (basal metabolic rate) | Energy to keep you alive at complete rest | The largest part for most people; mainly set by body size, sex and age |
| TEF (thermic effect of food) | Energy used to digest, absorb and process food | Commonly estimated at around 10% of what you eat; protein costs more to process than carbs or fat |
| EAT (exercise activity) | Planned workouts, sport, runs and gym sessions | Anywhere from almost nothing to a large share, depending on training |
| NEAT (non-exercise activity) | Walking, standing, fidgeting, chores, a physical job | Varies hugely between people and from day to day |
Why NEAT is the hidden variable
Most people think of "activity" as exercise, but for many, everyday movement adds up to more. Someone who walks to work, takes the stairs and is on their feet all afternoon can burn noticeably more than someone with the same gym routine who sits most of the day. NEAT also tends to drop a little, often without you noticing, when you eat less, which is one reason weight loss slows over time.
TDEE vs BMR: what is the difference?
The two are easy to mix up, but they answer different questions:
- BMR is what you would burn lying still all day. It is a building block, not an eating target.
- TDEE is what you actually burn on a normal day, including all movement and digestion. It is the number to compare your intake against.
You may also see RMR (resting metabolic rate). It is measured under slightly less strict conditions than BMR and is usually a little higher, but in everyday use the two are treated as near enough the same.
Good to know: a common mistake is eating at your BMR, thinking it is your maintenance level. For most people that is a much larger deficit than intended, and it can leave you tired and hungry. Your TDEE is always higher than your BMR.
How to calculate TDEE
The standard method has two steps: estimate BMR with an equation, then multiply by an activity factor.
Step 1: Estimate BMR with Mifflin-St Jeor
The Mifflin-St Jeor equation is the formula most modern calculators use:
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
To convert: kilograms = pounds ÷ 2.205; centimetres = inches × 2.54.
Step 2: Multiply by an activity factor
| Activity level | Typical week | Multiplier |
|---|---|---|
| Sedentary | Desk job, little or no exercise | 1.2 |
| Lightly active | Light exercise 1 to 3 days a week | 1.375 |
| Moderately active | Moderate exercise 3 to 5 days a week | 1.55 |
| Very active | Hard exercise 6 to 7 days a week | 1.725 |
| Extra active | Very hard training or a physical job plus training | 1.9 |
BMR × activity factor = estimated TDEE.
Worked example: calculating TDEE
Sam is a 29-year-old woman, 170 cm (5 ft 7 in) tall, weighing 65 kg (143 lb). She works at a desk and runs three times a week.
- BMR: (10 × 65) + (6.25 × 170) − (5 × 29) − 161 = 650 + 1,062.5 − 145 − 161 = about 1,407 calories.
- Activity factor: three runs a week fits "moderately active", so 1.55.
- TDEE: 1,407 × 1.55 = about 2,180 calories a day.
If Sam wanted to maintain her weight, about 2,180 calories a day would be her starting point. If she wanted to lose weight gradually, a deficit of 300 to 500 calories would give a target of roughly 1,680 to 1,880. Our guide to the calorie deficit for weight loss explains how to choose.
Now see how the activity level alone changes the result for the same person:
| Sam's activity level | Multiplier | Estimated TDEE |
|---|---|---|
| Sedentary | 1.2 | ~1,690 |
| Lightly active | 1.375 | ~1,935 |
| Moderately active | 1.55 | ~2,180 |
| Very active | 1.725 | ~2,425 |
The gap between "sedentary" and "very active" is over 700 calories a day. Choosing the right level is the biggest judgement call in the whole calculation.
Tip: if you are torn between two activity levels, pick the lower one. It is easy to eat a little more later if you lose weight faster than planned.
Why your calculated TDEE is only an estimate
Equations like Mifflin-St Jeor are built from averages. They are a good starting point for most healthy adults, but your real TDEE can sit a couple of hundred calories either side. Reasons include:
- Body composition. The equation uses weight, not muscle. Two people of the same weight can have different needs.
- Activity labels are fuzzy. "Moderate exercise" means different things to different people, and NEAT is not captured well by any label.
- Exercise estimates are rough. Calories burned shown by fitness trackers and gym machines are estimates too. See whether to eat back exercise calories for how to handle them.
- Individual variation. Genetics, hormones, sleep and health all play a part.
None of this makes the calculation useless. It just means the number is a hypothesis to test, not a fact.
How to find your real TDEE from tracking
The most accurate everyday way to learn your TDEE is to compare what you eat with what your weight does. You need two to four weeks of reasonably consistent logging and regular weigh-ins.
- Log your food as accurately as you reasonably can and work out your average daily intake.
- Weigh yourself several times a week and compare the average of your first week with the average of your last week.
- Convert the change into calories using the approximation of about 3,500 calories per pound (about 7,700 per kilogram), then spread it across the days.
Worked example: over 3 weeks (21 days) you averaged 2,000 calories a day and your weekly average weight fell by 1.5 lb (about 0.7 kg). That is roughly 1.5 × 3,500 = 5,250 calories of stored energy, or 5,250 ÷ 21 = 250 calories a day. So your real TDEE is about 2,000 + 250 = 2,250 calories.
Two cautions. Skip the first week or two of a new diet, when water and glycogen changes exaggerate the drop. And the result is only as good as your logging; if portions are often guessed low, your calculated TDEE will come out low too. Our guide on how to count calories covers the common blind spots.
How to use your TDEE
Once you have an estimate, it becomes the anchor for every other number:
- Maintain: eat around your TDEE. Expect your weight to drift up and down a little from day to day while the average stays flat.
- Lose weight: eat below it. A deficit of 300 to 500 calories is a common, sustainable range for most adults. For Sam, that means roughly 1,680 to 1,880 calories a day.
- Gain weight or build muscle: eat slightly above it, for example 250 to 500 calories more. For Sam, that would be roughly 2,430 to 2,680 calories, ideally paired with strength training.
Your TDEE also helps set nutrient targets. A common fibre guideline is about 14 g per 1,000 calories, so at 2,180 calories Sam would aim for around 30 g. Protein is often set from body weight instead: the adult RDA is 0.8 g per kg, which is 52 g a day for Sam at 65 kg (143 lb), and many people aim higher, particularly when active or losing weight.
Whatever your goal, keep intake above commonly cited minimums of around 1,200 calories a day for women and 1,500 for men unless you are under medical supervision.
Your TDEE changes over time
TDEE is not a fixed number. It moves with:
- Weight change. A smaller body uses less energy, so TDEE falls as you lose weight and rises as you gain. Recalculating every 4 to 5 kg (about 10 lb) keeps targets realistic.
- Activity. A new job, a new baby, an injury or a training block can shift it by hundreds of calories.
- Age. Needs tend to decline gradually over the decades, partly through lower activity and muscle loss.
- Eating less. When you diet, many people unconsciously move less, which nudges TDEE down further.
This is why weight loss often slows down over time even when you keep eating the same amount. If that is happening to you, read our guide to the weight loss plateau.
Thymi does the first estimate for you, calculating a calorie target from your body, activity, goal and pace with a Mifflin-St Jeor based formula, and lets you adjust it. Because it also logs your weight with a smoothed trend line, you can see over a few weeks whether that estimate matches reality.
Frequently asked questions
What does TDEE stand for?
TDEE stands for total daily energy expenditure. It is the total number of calories your body uses in a day, including your basal metabolic rate, the energy used to digest food, exercise and everyday movement such as walking and standing.
What is the difference between TDEE and BMR?
BMR (basal metabolic rate) is the energy your body uses at complete rest just to stay alive. TDEE is your BMR plus everything else you burn in a day, including digestion, exercise and daily movement. TDEE is always higher than BMR and is the number to compare your eating against.
How do I calculate my TDEE?
Estimate your BMR with the Mifflin-St Jeor equation, then multiply it by an activity factor: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active or 1.9 for extra active. The result is your estimated maintenance calories.
Should I eat at my TDEE or my BMR to lose weight?
Neither exactly. To lose weight, eat somewhat below your TDEE, commonly 300 to 500 calories less. Eating at your BMR usually creates a much larger deficit than intended, which can be hard to sustain.
How accurate are TDEE calculators?
They give a reasonable starting estimate for most healthy adults, but your real TDEE may be a couple of hundred calories higher or lower. Tracking your intake and weight trend for two to four weeks is the best way to fine-tune it.
Does TDEE go down when you lose weight?
Yes. A smaller body uses less energy at rest and when moving, and many people also move a little less when eating less. That is why it helps to recalculate your TDEE every 4 to 5 kg (about 10 lb) of weight change.
This article is general information for healthy adults, not medical or nutritional advice. Talk to a doctor or registered dietitian before changing how you eat, especially if you are pregnant or breastfeeding, have or have had an eating disorder, have a medical condition, or take medication.