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BMR Calculator

Find your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor formula. Get calorie targets for weight loss, maintenance, or gain.

Find your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor formula. Get calorie targets for weight loss, maintenance, or gain.

Quick start: Enter your age, gender, height, and weight. → Pick your activity level (sedentary to very active). → The tool calculates your BMR (resting calorie burn) using Mifflin-St Jeor.

How to use BMR Calculator

  1. 1

    Enter your age, gender, height, and weight.

  2. 2

    Pick your activity level (sedentary to very active).

  3. 3

    The tool calculates your BMR (resting calorie burn) using Mifflin-St Jeor.

  4. 4

    See your TDEE — total daily calorie needs with activity factored in.

  5. 5

    Review suggested calorie targets for weight loss, maintenance, and weight gain.

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Who is BMR Calculator for?

People starting a weight-loss or fitness journey

Athletes tracking bulking or cutting macros

Nutritionists demoing numbers to clients

Anyone curious about their metabolism

Fitness coaches building meal plans

Why use BMR Calculator?

  • Uses the modern Mifflin-St Jeor equation — more accurate than older Harris-Benedict.
  • Includes both BMR (rest) and TDEE (with activity) calculations.
  • Provides calorie targets for three common goals (loss, maintain, gain).
  • Metric and imperial units supported.
  • Fully private — health data never leaves your browser.

Common use cases

  • Plan a calorie deficit for sustainable weight loss.
  • Calculate calorie surplus for muscle gain or bulking.
  • Set a baseline for maintenance during a diet break.
  • Support a fitness journal with accurate daily calorie targets.
  • Teach clients or friends about metabolic math.

Limitations & things to know

  • Estimates for healthy adults — not tuned for athletes, pregnancy, or medical conditions
  • Mifflin-St Jeor assumes standard body composition
  • Consult a dietitian for medical nutrition decisions

About BMR Calculator

Knowing your daily calorie needs is the foundation of any meaningful nutrition plan, whether your goal is weight loss, maintenance, or muscle gain. Xevon Tools' BMR Calculator uses the modern Mifflin-St Jeor equation — widely recognized as the most accurate for healthy adults — to compute your Basal Metabolic Rate (BMR). Then it factors in your activity level to produce your Total Daily Energy Expenditure (TDEE), the number of calories you actually burn per day. Beyond raw numbers, the tool provides practical calorie targets: a 500-calorie daily deficit for about one pound per week of fat loss, a maintenance figure to hold steady, and a 300-calorie surplus for lean muscle gain. Because everything runs in your browser, your weight, height, and age never leave your device — a meaningful privacy default given how many fitness apps monetize user data.

Frequently asked questions

BMR is calories burned at complete rest (lying in bed all day). TDEE is BMR multiplied by an activity factor representing your typical daily movement and exercise.
Mifflin-St Jeor was derived from a more recent, broader dataset and is generally accepted as the most accurate equation for modern populations.
Sedentary: desk job, no exercise. Light: 1-3 days/week. Moderate: 3-5 days/week. Active: 6-7 days/week. Very Active: physical job + daily training.
Yes. All calculations run in your browser. Nothing is uploaded or logged.

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<iframe src="https://xevontools.com/embed/bmr-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px;" title="BMR Calculator — Xevon Tools"></iframe>
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