# BMR Calculator (Basal Metabolic Rate)

Calculate your Basal Metabolic Rate (BMR) with the Mifflin-St Jeor equation. Find out how many calories your body burns at rest each day.

## What this calculates

Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions like breathing, circulation, and cell production while completely at rest. Use this calculator to estimate your BMR using the widely-accepted Mifflin-St Jeor equation.

## Inputs

- **Gender**
- **Weight** (kg) — min 1, max 500
- **Height** (cm) — min 50, max 300
- **Age** (years) — min 1, max 120

## Outputs

- **Basal Metabolic Rate** — Calories your body burns at complete rest
- **BMR per Hour** — Hourly calorie burn at rest

## Details

The Mifflin-St Jeor equation, published in 1990, is considered the most accurate BMR formula for most people. For men, the formula is: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5. For women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161. Your BMR represents the minimum calories your body needs; your actual daily calorie needs depend on your activity level (see the TDEE calculator).

## Frequently Asked Questions

**Q: What is the difference between BMR and TDEE?**

A: BMR is the number of calories your body burns at complete rest just to maintain basic bodily functions. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor to account for daily movement and exercise. TDEE represents your total daily calorie needs.

**Q: Which BMR formula is most accurate?**

A: The Mifflin-St Jeor equation is generally considered the most accurate BMR prediction formula for most adults. It was validated in a 2005 study by the American Dietetic Association as the best predictor of resting metabolic rate.

**Q: Can I use BMR to lose weight?**

A: You should never eat below your BMR for extended periods, as this can slow your metabolism and cause nutrient deficiencies. For weight management, calculate your TDEE and create a moderate calorie deficit. Always consult a healthcare professional or registered dietitian before starting a diet plan.

**Q: Does BMR change with age?**

A: Yes. BMR generally decreases with age due to loss of lean muscle mass and hormonal changes. This is why the Mifflin-St Jeor equation includes age as a factor. Regular exercise, especially strength training, can help maintain a higher BMR as you age.

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Source: https://vastcalc.com/calculators/health/bmr
Category: Health & Fitness
Last updated: 2026-04-21