BMR Calculator (Basal Metabolic Rate)

Estimate how many calories your body needs at rest using the Mifflin-St Jeor formula. Adjust for activity to understand your Total Daily Energy Expenditure (TDEE).

Unit System

Sex

Age:

years

Weight:

Height:

Activity Level

What is BMR and Why Is It Important?

BMR stands for Basal Metabolic Rate and represents the number of calories your body burns at rest to maintain vital functions. It's the base level of energy required to keep your heart beating, lungs breathing, and body temperature stable without any physical activity.

How Does This Calculator Work?

This tool uses the Mifflin–St Jeor equation, a widely accepted formula for estimating BMR based on your sex, age, weight, and height. After calculating BMR, it multiplies it by your selected activity factor to estimate Total Daily Energy Expenditure (TDEE).

Choosing the Right Activity Level

Sedentary: Little to no exercise.
Lightly active: Light exercise/sports 1–3 days/week.
Moderately active: Moderate exercise/sports 3–5 days/week.
Very active: Hard exercise/sports 6–7 days a week.
Extra active: Very hard daily exercise or physical job.

Tips to Maintain a Healthy Metabolism

Improving BMR isn’t only about genetics. You can help optimize your metabolism by:

Building muscle through resistance training.
Eating a balanced diet rich in protein and fiber.
Staying hydrated and getting quality sleep.
Avoiding crash diets that slow your metabolism.
Staying physically active every day.

Frequently Asked Questions (FAQs)

What’s the difference between BMR and RMR?

RMR (Resting Metabolic Rate) is similar to BMR but measured under less strict conditions. Both are very close in value and used interchangeably in most health tools.

How accurate is this BMR calculator?

It uses Mifflin–St Jeor, one of the most reliable formulas for estimating calorie needs. However, individual factors can cause variation. For medical purposes, consult a nutrition professional.

How often should I update my BMR?

Update your inputs whenever your weight, age, or activity level changes significantly.

Tips

Enter the dimensions in the same unit for consistency.
Results update automatically as you type.
Use the unit selector to convert between different measurement systems.

Need Help?

Check out our guide on how to use this calculator properly and understand the concepts behind it.

Learn how BMR works

Tips to Maintain a Healthy Metabolism

Improving BMR isn’t only about genetics. You can help optimize your metabolism by:

Building muscle through resistance training.

Eating a balanced diet rich in protein and fiber.

Staying hydrated and getting quality sleep.

Avoiding crash diets that slow your metabolism.