What is a healthy BMI?

Normal BMI is 18.5-24.9. Underweight is below 18.5, overweight is 25-29.9, and obese is 30+. However, BMI doesn't account for muscle mass - athletes often have 'overweight' BMI but low body fat. Use body composition measurements for more accuracy.

How do I calculate my BMI?

BMI = weight (kg) / height (m)². In imperial: BMI = (weight in lbs × 703) / (height in inches)². For example, 70 kg at 1.75m = 70 / (1.75 × 1.75) = 22.9 BMI.

Is BMI accurate for athletes?

BMI is often inaccurate for athletes because muscle weighs more than fat. A muscular person with 10% body fat might have an 'overweight' BMI of 27. For athletes, body fat percentage or DEXA scans provide better health assessment.

What BMI do professional athletes have?

It varies by sport. Marathon runners: 18-21, cyclists: 19-22, swimmers: 22-24, sprinters: 23-26, NFL players: 25-35+. A 'healthy' BMI depends on body composition, not just the number. Elite endurance athletes tend toward lower BMIs.

BMI Calculator for Runners - Body Mass Index

Understanding BMI for Athletes

Body Mass Index (BMI) is a simple calculation using height and weight to categorize weight status. While useful for general population screening, BMI has important limitations for athletes and highly active individuals.

BMI Categories

Underweight: BMI less than 18.5
Normal weight: BMI 18.5-24.9
Overweight: BMI 25.0-29.9
Obese: BMI 30.0 and above

BMI Limitations for Athletes

BMI doesn't distinguish between muscle and fat mass, which can lead to misclassification of athletic individuals:

Muscular Athletes: May have high BMI due to muscle mass, not excess fat
Endurance Athletes: Often have very low BMI, which may appear "underweight"
Body Composition: BMI doesn't account for body fat percentage

Sport-Specific Considerations

Distance Runners: Often have BMI 18-22, optimized for endurance
Cyclists: Similar to runners, with emphasis on power-to-weight ratio
Strength Athletes: May have BMI >25 due to muscle mass
Team Sport Athletes: BMI varies by position and sport demands

Alternative Assessments

For athletes, consider these additional measurements:

Body Fat Percentage: More accurate for body composition
Waist Circumference: Indicator of abdominal fat
Performance Metrics: Power-to-weight ratios
Health Markers: Blood pressure, cholesterol, fitness tests

The gear these numbers assume

Every pace, zone and power figure on this page assumes something is measuring it. These are the three that cover running, cycling and the threshold work in between.