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Calorie Calculator
Need one daily calorie number? This calorie calculator estimates your TDEE, the total calories you burn per day, from your weight, height, age, and activity level. It uses the Mifflin-St Jeor equation, the formula most nutrition professionals rely on. Eat near your TDEE to maintain weight, below it to lose, and above it to gain. Quick estimate, not medical advice.
How to use
- Enter your sex, age, weight, and height.
- Select the activity level that honestly matches your typical week.
- Click Calculate Calories.
- Use the TDEE as your maintenance target, then adjust up or down for your goal.
Worked example
Take a 30 year old man weighing 180 lb at 5 ft 10 in. In metric that is 81.6 kg and 177.8 cm. His BMR is 10 times 81.6 plus 6.25 times 177.8 minus 5 times 30 plus 5, which is about 1,783 calories at rest.
With moderate activity, multiply by 1.55 to get a TDEE of about 2,763 calories per day. For fat loss he might eat around 2,260, and for muscle gain around 3,060, adjusting from there based on the scale.
Making the number work for you
A calculator gives you a starting line, not a verdict. Eat at your estimated TDEE for two to three weeks and watch the weekly average weight. If it is flat, the estimate was right. If it drifts, adjust calories by 150 to 250 and repeat.
Most people pick too high an activity level on their first try. When in doubt, choose one level lower and let the scale prove you wrong.
Frequently asked questions
What does this calorie calculator tell me?
It estimates your TDEE, the total calories you burn per day, plus your BMR for reference. Eat near TDEE to maintain weight, below it to lose weight, and above it to gain weight.
Which formula does it use?
The Mifflin-St Jeor equation, published in 1990 and widely used in nutrition practice and research. It estimates BMR from sex, age, weight, and height, then applies an activity multiplier to get TDEE.
How is Mifflin-St Jeor different from Harris-Benedict?
Harris-Benedict is older, first published in 1919, and later research found Mifflin-St Jeor predicts measured energy needs more accurately for most people. That is why modern calculators and many professionals prefer Mifflin-St Jeor.
Why does activity level matter so much?
Activity is the most variable part of daily calorie burn. A sedentary office worker and a construction worker of the same size can differ by 1,000 calories or more per day. Pick the level that honestly matches your week, not your best week.
What are the limitations of the estimate?
The formula is built from average body composition data, so it does not separately account for muscle mass. Very muscular people may burn more than predicted, and people with higher body fat may burn less. Treat the result as a starting point and adjust from real weight trends.
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest just keeping your organs running. TDEE adds everything else: daily movement, exercise, and digesting food. TDEE is the number you actually eat against.
Should I recalculate as I lose weight?
Yes. A lighter body burns fewer calories, so your TDEE drops as you lose weight. Recalculate every 10 to 15 pounds lost, or about once a month, to keep your target accurate.