How to use the tdee and bmr calculator
- Pick the sex used by the equation, enter your age (18 or older), and choose US or metric units for height and weight.
- Choose a BMR formula. Mifflin-St Jeor is the default. Choose Katch-McArdle only if you have a body fat estimate, which you can get from the body fat calculator.
- Choose the activity level that best matches a normal week, not your best week.
- Read your BMR, your TDEE (maintenance calories) and the tables that show TDEE at every activity level and a few calorie targets.
Formula
Mifflin-St Jeor: BMR = 10 x kg + 6.25 x cm - 5 x age + 5 (male) or - 161 (female)
Revised Harris-Benedict, male: 13.397 x kg + 4.799 x cm - 5.677 x age + 88.362
Revised Harris-Benedict, female: 9.247 x kg + 3.098 x cm - 4.330 x age + 447.593
Katch-McArdle: BMR = 370 + 21.6 x lean mass in kg, where lean mass = weight x (1 - body fat %)
TDEE = BMR x activity multiplier (1.2, 1.375, 1.55, 1.725 or 1.9)
BMR is the energy your body uses at complete rest. TDEE adds the energy of movement, exercise and digestion. The multipliers are conventions, not measurements, so treat TDEE as a starting point and adjust from real results over a few weeks.
Worked example
A 35-year-old female who is 5 ft 6 in (167.64 cm) and 150 lb (68.04 kg) gets a Mifflin-St Jeor BMR of 10 x 68.04 + 6.25 x 167.64 - 5 x 35 - 161 = 1,392 kcal per day.
At the lightly active multiplier of 1.375, TDEE is 1,392.14 x 1.375 = 1,914 kcal per day. Sedentary (x1.2) gives 1,671, moderately active (x1.55) gives 2,158 and extra active (x1.9) gives 2,645.
A 30-year-old male at 180 cm and 80 kg has a Mifflin-St Jeor BMR of 1,780 kcal and a moderately active TDEE of 1,780 x 1.55 = 2,759 kcal. The revised Harris-Benedict equation gives 1,854 for the same person, and Katch-McArdle at 20 percent body fat gives 1,752. Spread like this is normal, which is why a single number should never be treated as exact.
BMR and TDEE in plain language
Your basal metabolic rate (BMR) is the number of calories your body would burn in a day at complete rest, just to keep organs working. Your total daily energy expenditure (TDEE) is BMR plus everything else: walking, chores, exercise and the energy used to digest food. People often search for the two terms separately, but they describe the same calculation, so this page gives both.
Calories in the "maintain" row are the amount that would hold your weight steady if the estimate were exactly right for you. Real bodies vary, so use it as a first guess and compare it with what your weight does over two to four weeks.
Choosing a formula
All three formulas are published equations fitted to groups of people, and they disagree by a few hundred calories for the same person.
- Mifflin-St Jeor (1990) uses weight, height, age and sex. It is the default because it is widely used and simple.
- Revised Harris-Benedict (Roza and Shizgal, 1984) is an older equation that tends to give slightly higher values for many people.
- Katch-McArdle uses lean body mass, so it ignores height, age and sex. It can be better for very muscular or very lean people, but only if your body fat estimate is reasonable.
Using the calorie targets
The goal table adds or subtracts 250 or 500 kcal a day. A common rule of thumb says about 3,500 kcal equals one pound of body weight, so 500 kcal a day is roughly one pound a week. That rule is a simplification: bodies adapt, water weight moves, and the numbers drift over time. If a target falls below your BMR, the tool warns you. Very low intake is a decision to make with a doctor or dietitian, not a calculator. To turn calories into grams, use the macro calculator.
Assumptions and limits
- The equations estimate the average person with your inputs. Genetics, medications, thyroid conditions, pregnancy, illness and recent weight change can move real needs a lot.
- The activity multipliers are conventional values, not measured ones. Pick the level that fits an ordinary week, and move down a level if you are unsure.
- Adults only. The formulas were not built for children, teens or people under medical supervision.
- Everything is calculated in your browser. Nothing you type is sent anywhere.
- Results are rounded to whole calories after the exact calculation. They are estimates for general information, not medical advice, and not a diagnosis.
Frequently asked questions
Is TDEE the same as BMR?
No. BMR is the calories you burn at rest. TDEE is BMR multiplied by an activity factor, so it also includes movement and exercise. This page shows both so you can see how much of your day is baseline and how much is activity.
Which BMR formula is most accurate?
No formula is exact for every person. Mifflin-St Jeor is a common default, the revised Harris-Benedict equation is an older alternative, and Katch-McArdle depends on a body fat estimate. Comparing all three on this page shows the plausible range for you.
How many calories should I eat to lose weight?
This tool does not recommend a diet. It shows maintenance calories and a few offsets of 250 or 500 kcal a day as a rule-of-thumb illustration. A doctor or registered dietitian can set a safe plan for your situation.
Why does my TDEE look too high or too low?
The activity multiplier is the biggest source of error. Choosing moderately active instead of lightly active changes the result by several hundred calories. Try the level below your first guess and watch your actual weight trend.
Does muscle change my metabolism?
Lean mass is more metabolically active than fat mass, which is why Katch-McArdle is built on it. Meaningful changes in BMR generally come from large changes in body size and composition, not from small ones.