BMI Calculator
Calculate your Body Mass Index (BMI) to assess your weight category. Supports both metric (kg/cm) and imperial (lbs/in) units.
How to Use Our BMI Calculator
Step-by-Step Guide
Select Unit System
Choose between Metric (kg/cm) or Imperial (lbs/in) units
Enter Your Measurements
Input your weight and height accurately
Add Optional Details
Include age and gender for more personalized results
Get Your Results
View your BMI, category, and personalized recommendations
Pro Tips for Accurate Results
Measure at the same time
Weigh yourself at the same time of day for consistency
Use accurate measurements
Ensure your scale and measuring tools are calibrated
Consider body composition
BMI doesn't distinguish between muscle and fat mass
BMI Categories & Health Implications
Underweight (<18.5)
Health Risks:
- • Nutritional deficiencies
- • Weakened immune system
- • Osteoporosis risk
- • Fertility issues
Normal (18.5-24.9)
Health Benefits:
- • Lower disease risk
- • Better mobility
- • Improved energy
- • Longevity
Overweight (25-29.9)
Health Risks:
- • Type 2 diabetes
- • High blood pressure
- • Heart disease
- • Joint problems
Obese Class I (30-34.9)
Health Risks:
- • Severe health complications
- • Sleep apnea
- • Cancer risk
- • Mental health issues
Obese Class II (35-39.9)
Health Risks:
- • Very high health risks
- • Limited mobility
- • Quality of life impact
- • Medical intervention needed
Obese Class III (>40)
Health Risks:
- • Extreme health risks
- • Life-threatening conditions
- • Immediate medical care
- • Specialized treatment
Advanced BMI Metrics Explained
BMI Prime
BMI Prime is the ratio of your BMI to the upper limit of normal BMI (25). It provides a quick assessment of how much your BMI differs from the normal range.
Ponderal Index
The Ponderal Index uses height cubed instead of squared, making it more reliable for very tall or short individuals where BMI may be misleading.
Related Health Calculators
Body Fat Calculator
Calculate body fat percentage using various methods
Calorie Calculator
Determine daily calorie needs for weight management
Ideal Weight Calculator
Find your ideal weight based on height and frame
BMR Calculator
Calculate your Basal Metabolic Rate
Waist-to-Hip Ratio
Assess body fat distribution and health risks
Macro Calculator
Calculate macronutrient needs for your goals
Frequently Asked Questions
What is a healthy BMI range?
A healthy BMI typically falls between 18.5 and 24.9. However, BMI should be considered alongside other factors like muscle mass, age, and overall health.
Can BMI be misleading for athletes?
Yes, BMI can be misleading for athletes or very muscular individuals because muscle weighs more than fat. Consider additional measurements like body fat percentage.
How often should I check my BMI?
For most people, checking BMI monthly is sufficient. Focus more on long-term trends rather than daily fluctuations, which can be affected by water retention and other factors.
What should I do if my BMI is in the overweight or obese range?
Consult with a healthcare professional to develop a safe and effective weight management plan. Focus on sustainable lifestyle changes including diet and exercise.
Is BMI Prime more accurate than regular BMI?
BMI Prime provides a quick ratio comparison to the normal BMI upper limit (25), making it easier to understand how far you are from the normal range. Both metrics are useful for different purposes.