BMR Calculator

Estimate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor Equation.

Introduction

Welcome to the BMR Calculator! This tool helps you estimate your Basal Metabolic Rate (BMR), the number of calories your body needs at rest to maintain basic functions like breathing and circulation. Using the Mifflin-St Jeor Equation, it provides an accurate estimate based on your height, weight, age, and gender. You can input your measurements in various units, and the result will be shown in calories per day.

Height Unit:

Height:

Height (Inches):

Height (Centimeters):

Height (Meters):

Weight Unit:

Weight:

Age (Years):

Gender:

How to Use

Select your preferred height unit (feet/inches, inches, centimeters, or meters).
Enter your height in the selected unit.
Select your preferred weight unit (pounds or kilograms).
Enter your weight in the selected unit.
Enter your age in years.
Select your gender (male or female).
Click "Calculate" to see your BMR in calories per day.
Click "Save Calculation" to store your results locally.
Use "Reset" to clear all inputs and start over.

Understanding BMR

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body needs at rest to maintain basic physiological functions, such as breathing, circulation, and cell production. It represents the minimum energy required to keep your body functioning while at rest, not accounting for physical activity or digestion.

How We Calculate

We use the Mifflin-St Jeor Equation, which is considered one of the most accurate methods for estimating BMR:
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
The result is in calories per day.

Unit Conversions

The calculator converts your inputs to the units required by the Mifflin-St Jeor Equation (height in cm, weight in kg):
- Height: 1 foot = 12 inches, 1 inch = 2.54 cm, 1 meter = 100 cm
- Weight: 1 lb = 0.453592 kg, 1 kg = 2.20462 lbs

Using Your BMR

Your BMR is a starting point for determining your daily calorie needs. To estimate your total daily energy expenditure (TDEE), multiply your BMR by an activity factor:
- Sedentary (little or no exercise): BMR × 1.2
- Lightly active (light exercise 1-3 days/week): BMR × 1.375
- Moderately active (moderate exercise 3-5 days/week): BMR × 1.55
- Very active (hard exercise 6-7 days/week): BMR × 1.725
- Extremely active (very hard exercise, physical job): BMR × 1.9
This can help you plan your diet for weight maintenance, loss, or gain.

Limitations

The Mifflin-St Jeor Equation provides an estimate and may not be accurate for everyone. Factors like muscle mass, genetics, and health conditions can affect your actual BMR. For a more precise measurement, consider a professional assessment using methods like indirect calorimetry.

FAQs

What’s the difference between BMR and TDEE?

BMR is the number of calories your body needs at rest, while TDEE (Total Daily Energy Expenditure) includes calories burned through activity and digestion. TDEE is calculated by multiplying your BMR by an activity factor.

Can I use BMR to lose weight?

Yes, your BMR can help you estimate your daily calorie needs. To lose weight, consume fewer calories than your TDEE (BMR × activity factor). A deficit of 500-1000 calories per day can lead to a safe weight loss of 1-2 lbs per week.

What if I don’t know my measurements in metric units?

You can input your height and weight in any supported unit (feet/inches, inches, centimeters, meters for height; pounds or kilograms for weight), and the calculator will automatically convert them for the calculation.

About This Calculator

Built by xAI, this BMR Calculator uses the Mifflin-St Jeor Equation to estimate your Basal Metabolic Rate, with support for multiple units. For personalized advice, consult a healthcare provider or nutritionist.