Two trusted equations
Get the modern Mifflin-St Jeor result and the revised Harris-Benedict figure side by side, so you can see the realistic range.
BMR Calculator (Basal Metabolic Rate)
The calories your body burns at complete rest, from two trusted equations.
- Input
- No upload needed — instant
- Privacy
- Nothing is uploaded
- Cost
- Free · no sign-up · no watermark
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Overview
About the BMR Calculator (Basal Metabolic Rate)
Calculate your basal metabolic rate (BMR) — the calories your body burns at rest — with the Mifflin-St Jeor and Harris-Benedict equations from age, sex, height and weight.
Your basal metabolic rate is the calories your body burns if you did nothing all day but breathe. It is the largest part of your daily energy use and the foundation every diet plan is built on. Enter your age, sex, height and weight and this calculator returns your BMR from the two most-used equations.
The equations
Mifflin-St Jeor (men): 10·kg + 6.25·cm − 5·age + 5
Mifflin-St Jeor (women): 10·kg + 6.25·cm − 5·age − 161The revised Harris-Benedict equation is shown alongside it. Both estimate resting energy from the same four inputs; Mifflin-St Jeor is generally preferred today.
From BMR to daily calories
BMR alone is not what you eat to maintain weight. Multiply it by an activity factor — about 1.2 for sedentary up to 1.9 for very active — to get your TDEE. The TDEE calculator does that step and adds cut and bulk targets.
Private and precise
This calculator produces estimates from published formulas and is not medical advice. For anything about your health, talk to a doctor or a registered dietitian.
Step by step
How to use the BMR Calculator (Basal Metabolic Rate)
Choose your units and biological sex.
Enter your age, height and weight.
Read your BMR in calories per day, with Harris-Benedict shown alongside.
Why use it
Benefits and common use cases
What this tool is good for, and what it deliberately does not try to do.
Metric or imperial
Enter height and weight in centimetres and kilograms, or inches and pounds — the maths is handled for you.
The base for everything
BMR is the starting point for TDEE, cutting and bulking, so it is the number to know before you plan calories.
Questions
Frequently asked questions
Short, honest answers about quality, limits and privacy.
What is basal metabolic rate?
BMR is the number of calories your body needs each day just to stay alive at complete rest — breathing, circulation, cell repair and brain function. It is roughly 60–70% of the calories most people burn in a day.
Which equation is more accurate?
Mifflin-St Jeor is generally considered the most accurate for the general population and is what most dietitians use, so it is the headline figure here. Harris-Benedict tends to overestimate slightly.
Is BMR the same as the calories I burn?
No. BMR is only rest. Your total daily burn (TDEE) is BMR multiplied by an activity factor that accounts for movement and exercise.