BMR Calculator
Calculate your basal metabolic rate with Mifflin-St Jeor or Katch-McArdle equations. Know how many calories you burn at rest.
BMR
1,618 kcal
Sedentary need
1,941 kcal
x1.2 — mostly desk work
Moderate need
2,507 kcal
x1.55 — 3-5 workouts/week
BMR is calories at complete rest. Multiply by an activity factor (1.2–1.9) for total daily needs.
How it works
Mifflin-St Jeor: male 10W + 6.25H − 5A + 5; female 10W + 6.25H − 5A − 161. Katch-McArdle: 370 + 21.6 × lean mass.
Example: male 70 kg / 170 cm / 30 yr → BMR 1,618 kcal.
Last updated: March 2026
How this calculator is verified
Checked by True Calculator automated test suite on
- Formula verified against a published worked example in the automated test suite
- Edge cases (zero, negative, boundary and unit-mismatch inputs) covered by unit tests
The full verification method is on our how we verify page. Found an error? Tell us and we will re-check it.
When to Use This Calculator
Use the BMR calculator when you want to know the calories your body burns just to stay alive, before any activity. That number is the foundation of every diet plan in India: your daily calorie target is your BMR multiplied by an activity factor, so knowing it tells you whether you are eating above or below maintenance. Dietitians use it to set weight-loss and weight-gain plans, and gym-goers use it to decide how much they can eat on rest days. Students of nutrition and fitness courses verify their textbook calculations here, and people with thyroid or metabolic concerns use the result to discuss their energy needs with a doctor. Choose the Mifflin-St Jeor equation unless you know your body fat percentage, which unlocks the Katch-McArdle option.
How to Use This Calculator
- Step 1: Enter your sex, age, weight and height in the first fields.
- Step 2: Choose the Mifflin-St Jeor equation if you do not know your body fat percentage.
- Step 3: Choose Katch-McArdle instead if you have a recent body fat reading, and enter that percentage.
- Step 4: Read your BMR in calories, which is the energy your body burns at complete rest before any daily activity is added.
Worked Example
A 30-year-old woman in Chennai who is 160 cm tall and weighs 55 kg chooses the Mifflin-St Jeor equation. The formula, 10 times weight plus 6.25 times height minus 5 times age minus 161, gives a resting burn of about 1,239 calories. If she selects Katch-McArdle instead and enters a body fat percentage of 20, the calculator works out her lean mass of 44 kg (55 kg less 20% fat) and returns about 1,320 calories — 370 plus 21.6 times the lean mass. BMR is the energy spent lying still, before activity is added.
Tips and Common Mistakes
- •Tip 1: Use Katch-McArdle only with a recent body fat measurement, because guessing the percentage can make it less accurate than Mifflin-St Jeor.
- •Tip 2: Recalculate BMR after a significant weight change, since both equations depend on your current body weight.
- •Tip 3: Multiply your BMR by an activity factor to get daily needs, since BMR alone is not the number you eat to.
- ✗Mistake 1: Confusing BMR with total daily needs; BMR excludes all activity, so eating exactly at BMR would be an extreme deficit.
- ✗Mistake 2: Entering body fat as a fraction like 0.2 when the field expects a percentage like 20.
Frequently Asked Questions
What is BMR?
BMR (basal metabolic rate) is the energy your body burns at complete rest just to stay alive — breathing, heartbeat, body temperature. It is usually 60–70% of your total daily burn.
Which BMR formula is most accurate?
Mifflin-St Jeor is considered the most accurate for the general adult population. Katch-McArdle is better for athletes because it uses lean body mass directly.
How do I turn BMR into daily calories?
Multiply BMR by an activity factor: 1.2 for sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active. That gives your maintenance calories.
Does BMR decrease with age?
Yes. Muscle mass typically declines with age, and BMR drops by roughly 2% per decade after adulthood. Strength training helps slow that decline.
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