BMR and TDEE Calculator for Daily Calories

What it is

Before you plan a diet or a bulk, it helps to know roughly how much energy your body uses in a day. Enter your sex, age, height and weight and this calculator estimates your basal metabolic rate (BMR), the calories you burn at rest, and your total daily energy expenditure (TDEE) once activity is included. Pick maintain, lose or gain, set how many calories to cut or add, and it shows a daily target and the weekly weight change that implies. A comparison table runs the same inputs through up to four published equations, so you can see how much they disagree. The form opens with an example person (male, 30, 175 cm, 70 kg) so a result appears immediately. Only centimeters and kilograms are supported, and everything is calculated in your browser.

How to use

1. Choose your sex and enter age in whole years, height in cm and weight in kg.
2. Leave the equation on Mifflin-St Jeor, or pick another. Add a body fat percentage if you want Katch-McArdle.
3. Pick an activity level, or type your own activity factor.
4. Choose maintain, lose or gain, and set the daily calorie change.
5. Read the BMR, TDEE and target, then check the comparison table and the worked math.

How it works

• Mifflin-St Jeor: 10 x weight + 6.25 x height - 5 x age, plus 5 for men or minus 161 for women (Mifflin MD et al., Am J Clin Nutr 1990;51(2):241-247, original paper checked).
• Harris-Benedict, revised by Roza AM and Shizgal HM (Am J Clin Nutr 1984) and original by Harris JA and Benedict FG (PNAS 1918). These coefficients come from secondary literature and the original scans were not checked.
• Katch-McArdle: 370 + 21.6 x lean body mass in kg, where lean mass is weight x (1 - body fat). Also a secondary source, original not checked.
• TDEE = BMR x activity factor. Target = TDEE minus or plus the calorie change you enter.
• Weekly change = daily difference x 7 / 7,000 kg, using the rough 7,000 kcal per kg figure (Samsung Medical Center health information, secondary source).
• Accepted ranges are age 15 to 100 (whole years), height 100 to 250 cm, weight 30 to 300 kg, activity factor 1 to 3 and body fat 2 to 70 percent.
• Calories are calculated with decimals and rounded to whole numbers once, for display. The math lines show two decimals.
• For reference the page also lists the energy requirement for low activity from the 2025 Korean Dietary Reference Intakes (Ministry of Health and Welfare and the Korean Nutrition Society, 2025-12) for your age band. Retrieved 2026-10-04.

Examples

Male, 30, 175 cm, 70 kg, lightly active (1.375), maintaining weight.

Item	Math	Result
BMR (Mifflin-St Jeor)	10 x 70 + 6.25 x 175 - 5 x 30 + 5	1,648.75, shown as 1,649 kcal
TDEE	1,648.75 x 1.375	2,267 kcal
Target for a 500 kcal cut	2,267 - 500	1,767 kcal
Weekly change	-500 x 7 / 7,000	-0.5 kg

With the same inputs the revised Harris-Benedict equation gives a BMR of 1,696 kcal and the original gives 1,702 kcal, so the equations differ by tens of calories.

Good to know

This is a rough estimate for reference. It does not diagnose or treat anything, so talk to a doctor or dietitian if you have a health condition or plan a big change in how you eat. Equations describe an average person and can miss your real energy use by a few hundred kcal because of muscle mass, genetics and daily habits. The most reliable method is to track what you eat and how your weight moves over a few weeks, then adjust the target to fit.