🧮

BMR Calculator – Basal Metabolic Rate & TDEE (Mifflin‑St Jeor)

BMR Calculator

The BMR Calculator (Basal Metabolic Rate) estimates the number of calories your body burns at complete rest. This basal metabolic rate calculator uses the Mifflin‑St Jeor equation, considered the most accurate for most people. It also calculates your Total Daily Energy Expenditure (TDEE) based on your activity level. Knowing your BMR and TDEE is essential for weight loss, weight gain, or weight maintenance. Whether you are an athlete, a dieter, or simply curious about your metabolism, this calorie calculator provides a personalised starting point.

Basal Metabolic RateBMR~60‑75% of TDEEActivity15‑30%Thermic~10%TDEE = BMR + Activity + Thermic EffectUse to plan weight loss, gain, or maintenance

BMR Formulas (Mifflin‑St Jeor)

For women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

For men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5

TDEE = BMR × activity factor (1.2 to 1.9)

How to Use This BMR Calculator

  1. Select your gender.
  2. Enter your age, weight (kg), and height (cm).
  3. Choose your typical activity level.
  4. Click “Calculate” to see your BMR and TDEE.

Why BMR Matters for Weight Management

Your BMR accounts for 60‑75% of your daily energy expenditure. By knowing your BMR, you can avoid eating too few calories (which can slow metabolism) or too many (which leads to weight gain). Once you have your BMR and TDEE, you can set a calorie target that aligns with your goal: subtract 300‑500 calories for weight loss, add 300‑500 for weight gain, or eat at TDEE for maintenance.

Factors that affect BMR include age (BMR decreases with age), muscle mass (more muscle increases BMR), body size, and genetics. Strength training can raise your BMR by increasing lean muscle mass. This basal metabolic rate calculator gives you a baseline; track changes over time as your body composition improves.

Use this BMR calculator in combination with a food diary to achieve your health goals. Bookmark this calorie calculator and metabolism calculator to check your progress monthly.

The Role of Muscle in BMR

Muscle tissue is metabolically active – it burns more calories at rest than fat tissue. Increasing your muscle mass through resistance training can raise your BMR by 50‑100 calories per pound of muscle gained. This is why combining strength training with calorie control is more effective for long‑term weight management than diet alone.

Frequently Asked Questions

  • Is Mifflin‑St Jeor better than Harris‑Benedict? Yes, studies show Mifflin‑St Jeor is more accurate for modern, sedentary populations.
  • How often should I recalculate my BMR? Every 5‑10 kg of weight change or every 3‑6 months.
  • Can I use this for athletes? Yes, but athletes may need a higher activity factor and may benefit from a body composition assessment.
  • Does BMR change during pregnancy? Yes, it increases significantly. Pregnant women should consult a doctor.

Bookmark this BMR calculator to use it as your go‑to basal metabolic rate calculator, TDEE calculator, and weight loss calculator.

Step‑by‑Step Manual Example

Female, 30y, 65kg, 165cm, moderate activity:

BMR = (10×65) + (6.25×165) − (5×30) − 161 = 650 + 1031.25 − 150 − 161 = 1370 cal/day

TDEE = 1370 × 1.55 = 2124 cal/day

Frequently Asked Questions about BMR

What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain basic life functions (breathing, circulation, cell production). It accounts for 60‑75% of your daily energy expenditure.
Which BMR formula is most accurate?
The Mifflin‑St Jeor equation is considered the most accurate for most people. It was developed in 1990 and is widely used by nutritionists.
How can I use my BMR to lose weight?
To lose weight, create a calorie deficit by eating fewer calories than your TDEE (Total Daily Energy Expenditure). A deficit of 500 calories per day leads to about 0.5 kg (1 lb) of weight loss per week.
Does muscle mass affect BMR?
Yes, muscle tissue burns more calories at rest than fat. Increasing muscle through strength training raises your BMR, helping with weight management.