BMR & Calorie Calculator

Estimate your Basal Metabolic Rate and daily calorie needs based on your age, sex, height, weight and activity level.

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How to use the BMR

Fill in each input field with your own numbers.
Results calculate automatically and update as you change any value.
Read the result cards below the inputs for the full breakdown.
Adjust any field to explore different scenarios instantly.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About BMR

What is BMR?

Basal Metabolic Rate is the energy your body uses at complete rest to keep you alive — breathing, circulation and cell function. It is the foundation of your daily calorie needs.

Mifflin-St Jeor equation

This tool uses the Mifflin-St Jeor formula, widely regarded as one of the most accurate predictive equations for BMR.

Activity multiplier

Your maintenance calories are BMR multiplied by an activity factor, from sedentary (1.2) to very active (1.9). Eat below maintenance to lose weight, above to gain.

Frequently asked questions

How accurate is this?

It is a well-validated estimate, but individual metabolism varies. Use it as a starting point.

What are maintenance calories?

The daily calories to keep your current weight, given your activity level.

How do I lose weight?

Eat in a moderate deficit below maintenance and combine with activity; consult a professional for plans.