Free BMR Calculator Online 2026
Calculate your Basal Metabolic Rate instantly โ using the clinically validated Mifflin-St Jeor and Harris-Benedict equations. Get your TDEE, daily calorie goals for weight loss or muscle gain. Metric & imperial. Free, no sign-up.
๐ซ BMR & TDEE Calculator
Enter your details below โ results update instantly
| Activity Level | Multiplier | Daily Calories |
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What Is BMR? โ Basal Metabolic Rate Explained
Your Basal Metabolic Rate (BMR) is the total number of calories your body requires per day to sustain essential biological functions while in a state of complete rest โ including breathing, blood circulation, cellular repair, temperature regulation, and brain function. Think of BMR as your body's "idle speed": the energy cost of simply being alive.
BMR accounts for approximately 60โ75% of your total daily energy expenditure for most sedentary to lightly active adults. This makes it the single most important number in any nutrition, weight loss, or athletic performance plan. Knowing your BMR means you can set calorie targets that are actually grounded in your unique physiology rather than generic diet advice.
How to Use This Free BMR Calculator
Using our BMR calculator takes under 30 seconds. Simply enter your age, weight, height, and biological sex, choose your activity level, and select your preferred formula (Mifflin-St Jeor is recommended for most adults). Hit "Calculate" to instantly receive:
- Your precise BMR in kilocalories per day
- Your TDEE (Total Daily Energy Expenditure) at all five activity levels
- Personalised calorie targets for weight loss, maintenance, and muscle gain
- A visual gauge showing where your BMR sits relative to typical adult ranges
BMR Formula โ Mifflin-St Jeor Equation (Most Accurate for 2026)
The Mifflin-St Jeor formula, published in the American Journal of Clinical Nutrition in 1990, is the gold standard recommended by the Academy of Nutrition and Dietetics. It is more accurate than the older Harris-Benedict equation for non-obese adults.
Women: BMR = (10 ร weight in kg) + (6.25 ร height in cm) โ (5 ร age in years) โ 161
Example โ 35-year-old male, 80 kg, 180 cm:
BMR = (10 ร 80) + (6.25 ร 180) โ (5 ร 35) + 5 = 800 + 1,125 โ 175 + 5 = 1,755 kcal/day
Harris-Benedict Equation (Classic Formula)
Women: BMR = 447.593 + (9.247 ร kg) + (3.098 ร cm) โ (4.330 ร age)
Katch-McArdle Formula (Best for Athletes with Known Body Fat %)
Lean Body Mass = Weight ร (1 โ Body Fat %)
This formula is ideal for athletes and bodybuilders who know their body fat percentage, as it accounts for lean mass directly, making it independent of gender differences.
BMR vs TDEE โ What Is the Difference?
BMR is the calories your body burns at complete rest. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor to account for movement, exercise, and daily tasks. TDEE is the actual number of calories you need each day to maintain your current weight. To lose weight, consume below TDEE. To gain muscle, consume above TDEE.
Who Uses a BMR Calculator?
BMR calculators are widely used by fitness enthusiasts, personal trainers, registered dietitians, competitive athletes, people managing obesity or metabolic disorders, and anyone tracking macros for weight loss or muscle hypertrophy. Medical professionals in the USA, UK, Canada, Australia, Germany, UAE, and Singapore commonly use Mifflin-St Jeor as a first-pass screening tool for caloric prescription.
Frequently Asked Questions โ BMR Calculator 2026
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