BMR Calculator
Free BMR Calculator Online to calculate your Basal Metabolic Rate (BMR) using age, gender, height, and weight with Metric, US, or UK units. Get instant daily calorie estimates.
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About this BMR Calculator
This free BMR calculator estimates basal metabolic rate with the Mifflin–St Jeor equation, then projects daily maintenance calories (TDEE) from your activity level. For weight-loss calorie targets, use our free TDEE Calculator. Use Men or Women profiles with Metric, US, or UK units.
How to calculate BMR
- 1
Choose profile and units
Select Men or Women and Metric, US, or UK units.
- 2
Enter age, height, and weight
Fill in your details so the calculator can estimate resting calorie burn.
- 3
Pick activity and review targets
Choose an activity level to see TDEE plus mild deficit and surplus calorie guidance.
Why use this BMR calculator
Mifflin–St Jeor formula
A widely used clinical estimate for adult resting calorie needs.
Activity-aware TDEE
Map BMR to daily maintenance calories across five activity levels.
Metric, US & UK units
Enter measurements the way you already track them.
Quick calorie guidance
See mild deficit and surplus targets to support lose/gain goals.
How BMR Calculator Works - Calculation & Formulas
Basal Metabolic Rate (BMR) is an estimate of the calories your body burns at rest. This tool uses the Mifflin–St Jeor formula from weight, height, age, and sex, then multiplies by an activity factor to estimate daily maintenance calories (TDEE).
Men (Mifflin–St Jeor)
BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5Example: 80 kg, 178 cm, age 30 → (10 × 80) + (6.25 × 178) − (5 × 30) + 5 = 1,780 kcal/day
Women (Mifflin–St Jeor)
BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161Example: 65 kg, 165 cm, age 28 → (10 × 65) + (6.25 × 165) − (5 × 28) − 161 ≈ 1,381 kcal/day
TDEE from activity
TDEE = BMR × activity factorExample: Sedentary 1.2 · Light 1.375 · Moderate 1.55 · Very active 1.725 · Extra active 1.9. Example: 1,780 × 1.55 ≈ 2,759 kcal/day maintenance.
Why Mifflin–St Jeor
Published in 1990, Mifflin–St Jeor is widely used for adult resting energy estimates and is often preferred over older Harris–Benedict equations for modern populations.
Units conversion
Enter Metric (kg/cm), US (lb, ft/in), or UK (stone/lb, ft/in). The calculator converts inputs so the formula always runs in kilograms and centimeters.
Mild deficit & surplus
From TDEE, the tool shows approximate mild deficit (−250 kcal) and mild surplus (+250 kcal) targets as a starting point for lose/gain planning — not medical advice. For a weight-loss–focused view, open the TDEE Calculator.
Frequently asked questions - FAQs
Quick answers about BMR Calculator.
Yes. You can calculate BMR and TDEE online for free with no account required.
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