What formula does the BMR Calculator use?

It uses the Mifflin-St Jeor equation: 10 × weight in kg + 6.25 × height in cm − 5 × age + 5 for men or −161 for women. It is widely considered more accurate than the older Harris-Benedict formula.

How is BMR different from TDEE?

BMR is the calories your body burns at complete rest. TDEE (Total Daily Energy Expenditure) adds an activity multiplier on top of BMR to account for exercise and daily movement — use the TDEE Calculator once you have your BMR.

Can I use the BMR Calculator with pounds and feet/inches?

Yes. Toggle to US units and enter weight in pounds and height in feet and inches — the calculator converts to metric internally before applying the formula.

Is the BMR Calculator result medical advice?

No. It is a general estimate based on a standard formula and population averages, not a substitute for professional medical or nutritional advice. Talk to a doctor or registered dietitian for personalized guidance.

Does the BMR Calculator store or upload my weight and height?

No. The BMR Calculator computes everything locally in your browser. The numbers you enter are never uploaded to ArrayKit or stored anywhere.

Why do male and female results differ for the same weight and height?

The Mifflin-St Jeor equation applies a fixed offset — plus 5 for men and minus 161 for women — to account for average differences in body composition, so a female result is 166 calories lower than a male result with identical weight, height, and age.

BMR Calculator Online

Estimate your basal metabolic rate from weight, height, age, and sex, entirely on your device. A general estimate, not medical advice.

The BMR Calculator runs entirely in your browser. Your weight, height, age, and sex are never uploaded to ArrayKit, and the result is a general estimate, not medical advice.

Open the TDEE Calculator

About BMR Calculator

BMR Calculator estimates your basal metabolic rate — the number of calories your body burns each day just to keep your heart beating, lungs breathing, and cells functioning, before you add any movement or exercise. It uses the Mifflin-St Jeor equation, the formula most dietitians favor today because it tends to be more accurate across body types than older methods. Enter your weight, height, age, and sex in either metric or US units and the result updates instantly. Pair the number with an activity multiplier in the TDEE Calculator to see your full daily calorie need, or feed it into the Calorie Calculator or Macro Calculator to plan a target intake. This is a general estimate from a standard formula, not medical advice — everything runs locally in your browser and your figures are never uploaded.

Features

Uses the Mifflin-St Jeor equation, a formula favored by dietitians for its accuracy
Switch between metric (kg/cm) and US (lb, ft-in) units with one toggle
Separate results for male and female inputs, reflecting the formula's offset
Instant recalculation as you type — no submit button needed
Copy a plain-text summary of your inputs and BMR result
Clear error message if weight, height, or age is missing or invalid
Clean starting point for TDEE, calorie, and macro planning
Runs entirely in your browser — your body data is never sent anywhere

How to use the BMR Calculator

Choose metric or US units
Select male or female
Enter your weight, height, and age
Read your estimated BMR in calories per day
Open the TDEE Calculator to add an activity level

Example

Input

male, 80kg, 180cm, 30y

Output

BMR: 1,780 cal/day

10×80 + 6.25×180 − 5×30 + 5 = 1,780 calories per day at rest.

Common errors & troubleshooting

BMR seems too low compared to what I expected. — Basal metabolic rate only covers calories burned at complete rest. Add an activity multiplier in the TDEE Calculator to get your total daily calorie need.
Switching from metric to US units changes the result slightly. — Rounding in pound-to-kilogram and inch-to-centimeter conversion can shift the BMR by a calorie or two — enter precise figures for the closest match.
Result shows an error after entering height and weight. — Age must also be filled in and every field needs to be a number greater than 0 — check for a blank or negative value.
Height in feet and inches was typed as a decimal, like 5.11. — Enter feet and inches in the two separate boxes (5 and 11), not as a single decimal number, or the height will be calculated incorrectly.

Frequently asked questions

What formula does the BMR Calculator use?: It uses the Mifflin-St Jeor equation: 10 × weight in kg + 6.25 × height in cm − 5 × age + 5 for men or −161 for women. It is widely considered more accurate than the older Harris-Benedict formula.
How is BMR different from TDEE?: BMR is the calories your body burns at complete rest. TDEE (Total Daily Energy Expenditure) adds an activity multiplier on top of BMR to account for exercise and daily movement — use the TDEE Calculator once you have your BMR.
Can I use the BMR Calculator with pounds and feet/inches?: Yes. Toggle to US units and enter weight in pounds and height in feet and inches — the calculator converts to metric internally before applying the formula.
Is the BMR Calculator result medical advice?: No. It is a general estimate based on a standard formula and population averages, not a substitute for professional medical or nutritional advice. Talk to a doctor or registered dietitian for personalized guidance.
Does the BMR Calculator store or upload my weight and height?: No. The BMR Calculator computes everything locally in your browser. The numbers you enter are never uploaded to ArrayKit or stored anywhere.
Why do male and female results differ for the same weight and height?: The Mifflin-St Jeor equation applies a fixed offset — plus 5 for men and minus 161 for women — to account for average differences in body composition, so a female result is 166 calories lower than a male result with identical weight, height, and age.

Related tools

TDEE Calculator — Estimate total daily energy expenditure from BMR and activity level.
Calorie Calculator — Estimate daily calories to maintain, lose or gain weight from your stats.
Macro Calculator — Split your daily calories into protein, carbs and fat grams by ratio.
BMI Calculator — Calculate body mass index and see the healthy weight range for your height.
Body Fat Calculator — Estimate body fat percentage with the US Navy tape measurement method.
Calories Burned Calculator — Estimate calories burned by activity using MET values, weight and time.