TDEE vs BMR: What’s the Difference and Which to Use?
If you have ever used a calorie calculator, you have probably been shown two numbers: your BMR and your TDEE. They sound similar, they are both measured in calories, and they are often confused. The short answer is this: BMR is what your body burns at complete rest; TDEE is what you burn on a normal day once movement, exercise and digestion are added on. For planning what to eat, TDEE is almost always the number you want. This guide explains why, shows how each is calculated, and walks through two full examples with real numbers.
This article is general information, not medical advice. If you have a health condition, are pregnant, or are planning a significant change to your diet, speak to your GP or a registered dietitian first.
What BMR and TDEE actually measure
Basal metabolic rate (BMR) is the energy your body uses just to stay alive while lying still, awake, warm and having not eaten for several hours. It covers breathing, circulation, keeping your organs working, maintaining body temperature and repairing cells. You would burn roughly this much if you spent the entire day in bed.
You will also see RMR (resting metabolic rate). It is measured under slightly less strict conditions, so it usually comes out a little higher than BMR. For everyday purposes the two are treated as interchangeable, and most online calculators, including ours, are estimating the same thing.
Total daily energy expenditure (TDEE) is everything you burn in 24 hours. It is usually broken into four parts:
- BMR — typically the largest share for most people who are not very active.
- Thermic effect of food (TEF) — the energy used to digest and process what you eat, commonly estimated at around 10% of intake.
- Exercise activity — planned workouts such as running, gym sessions or sport.
- Non-exercise activity (NEAT) — walking to the shops, standing at work, housework, fidgeting. This varies enormously between people and is often bigger than formal exercise.
So BMR is one ingredient of TDEE, never the whole thing. Your TDEE will always be higher than your BMR.
BMR vs TDEE at a glance
| BMR | TDEE | |
|---|---|---|
| What it measures | Calories burned at complete rest | Calories burned across a whole normal day |
| Includes exercise? | No | Yes |
| Includes digestion and daily movement? | No | Yes |
| How it is estimated | Formula using weight, height, age and sex | BMR multiplied by an activity factor |
| Best used for | A baseline and a sense-check | Setting a daily calorie target |
| Changes with activity? | Only slowly (with weight or muscle change) | Day to day |
How to calculate BMR and TDEE, step by step
The most widely used formula today is the Mifflin-St Jeor equation, published in 1990. It works in metric units, so convert first if you think in pounds and inches (1 kg = 2.2046 lb; 1 inch = 2.54 cm).
- Measure your inputs. Weight in kilograms, height in centimetres, age in years.
- Calculate BMR.
- Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
- Choose an honest activity level from the table below.
- Multiply. TDEE = BMR × activity factor.
- Adjust for your goal. Eat around your TDEE to maintain weight, below it to lose, above it to gain.
| Activity level | Typical description | Multiplier |
|---|---|---|
| Sedentary | Desk job, little or no exercise | 1.2 |
| Lightly active | Light exercise 1–3 days a week | 1.375 |
| Moderately active | Moderate exercise 3–5 days a week | 1.55 |
| Very active | Hard exercise 6–7 days a week | 1.725 |
| Extra active | Physical job plus hard training | 1.9 |
Most people overestimate their activity level. If you exercise three times a week but sit for most of the rest of the day, “lightly active” is often closer to the truth than “moderately active”.
Worked example 1: a 35-year-old woman
Sarah is 35, weighs 68 kg (about 150 lb) and is 165 cm tall (about 5 ft 5 in). She walks most days and goes to three or four exercise classes a week, so she chooses moderately active.
Step 1 — BMR (Mifflin-St Jeor, female):
- 10 × 68 = 680
- 6.25 × 165 = 1,031.25
- 5 × 35 = 175
- 680 + 1,031.25 − 175 − 161 = 1,375 kcal per day
Step 2 — TDEE:
- 1,375.25 × 1.55 = about 2,132 kcal per day
That is the gap in a nutshell: Sarah’s body needs about 1,375 kcal just to tick over, but she actually burns about 2,132 kcal on a typical day — a difference of more than 750 kcal. If she set her intake at her BMR thinking it was her maintenance level, she would be in a deficit of roughly 35% without realising it.
If Sarah wants to lose weight gradually, a common starting point is to eat around 500 kcal below TDEE: 2,132 − 500 = about 1,630 kcal. That is still comfortably above her BMR, which is a sensible sense-check.
UK food labels show energy in both kcal and kilojoules. To convert, multiply by 4.184: Sarah’s TDEE is about 8,920 kJ and her BMR about 5,750 kJ.
Worked example 2: a 40-year-old man at every activity level
James is 40, weighs 85 kg (about 187 lb) and is 180 cm tall (about 5 ft 11 in).
BMR (Mifflin-St Jeor, male): (10 × 85) + (6.25 × 180) − (5 × 40) + 5 = 850 + 1,125 − 200 + 5 = 1,780 kcal.
Here is how his TDEE changes depending on how active he is:
| Activity level | Calculation | TDEE (kcal/day) |
|---|---|---|
| Sedentary | 1,780 × 1.2 | 2,136 |
| Lightly active | 1,780 × 1.375 | 2,448 |
| Moderately active | 1,780 × 1.55 | 2,759 |
| Very active | 1,780 × 1.725 | 3,070 |
| Extra active | 1,780 × 1.9 | 3,382 |
Notice that his BMR never changes in this table — only his TDEE does. The spread from sedentary to extra active is over 1,200 kcal a day, which is why choosing the right activity level matters far more than the decimal places in the BMR formula.
Which number should you use?
Use TDEE to set your daily calorie target. It reflects what you actually burn, so it is the right anchor whether you want to maintain, lose or gain weight. Our macro calculator starts from this same figure when splitting calories into protein, carbs and fat.
Use BMR as a floor and a sense-check. A widely used rule of thumb is not to set a long-term intake below your BMR without professional guidance, because very low intakes make it hard to get enough protein and nutrients and are difficult to sustain.
For context, the NHS uses a general reference of around 2,000 kcal a day for women and 2,500 kcal for men, and the US Dietary Guidelines give estimated needs of roughly 1,600–2,400 kcal for adult women and 2,000–3,000 kcal for adult men, depending on age and activity. Both sets of figures sit well above typical BMR values, which is another reminder that BMR is not a daily eating target. For weight loss, the CDC notes that people who lose weight gradually — about 1 to 2 lb (roughly 0.5 to 1 kg) a week — are more likely to keep it off.
Finally, remember that every formula is an estimate. Treat your TDEE as a starting point, track your weight for two to four weeks, and adjust by 100–200 kcal if the trend is not what you expected. Your real-world results beat any equation.
Frequently asked questions
Is TDEE the same as maintenance calories?
Yes, in practice. Your TDEE is the number of calories that, eaten consistently, should keep your weight roughly stable. “Maintenance calories” is simply the everyday name for it.
Should I eat my BMR to lose weight?
Usually not. Eating at BMR means you are eating far below what you burn — in the first example above, about 750 kcal under. A moderate deficit from TDEE (often 300–500 kcal a day) is easier to sustain and makes it simpler to meet protein and nutrient needs. If you are considering a very low-calorie diet, do so only under medical supervision.
Which BMR formula is most accurate?
Mifflin-St Jeor is generally considered the most reliable for most adults and is the one most calculators use. The older revised Harris-Benedict equation tends to give slightly higher results — for Sarah it gives about 1,436 kcal versus 1,375 kcal. If you know your body-fat percentage, the Katch-McArdle formula, which uses lean mass, can suit very lean or muscular people better.
Work out your own numbers
You do not need to do the arithmetic by hand. Enter your age, height, weight and activity level into our free TDEE calculator to see your daily calorie burn in seconds, in metric or imperial units. If you only want the resting figure, the BMR calculator gives you that on its own, and our guide to Leangains macros shows how to turn a TDEE figure into training-day and rest-day targets.
Not medical advice: calorie estimates are approximate and individual needs vary. Consult a GP, doctor or registered dietitian before making major changes to your diet.