BMI Calculator
BMI and weight category in metric or imperial.
- BMI
- 22.9
- Category
- Normal weight
BMI Calculator computes body mass index from height and weight in either metric or imperial units, then maps the result to the standard underweight, normal, overweight, and obese ranges. All math runs locally in your browser.
How it works
Choose metric or imperial units, enter your weight and height, and the tool applies the matching BMI formula—weight over height squared for metric, or weight times 703 over height squared for imperial—then shows your category.
Benefits
- Supports both metric and imperial units
- Categorizes results using standard BMI ranges
- Calculates instantly with no page reload
- Keeps all measurements on your device only
Use cases
- Get a quick general BMI reading before a check-up
- Track BMI changes over time alongside other metrics
- Compare metric and imperial BMI formulas for coursework
- Estimate a starting point before setting fitness goals
Best practices
- Use consistent units for weight and height each time
- Treat BMI as one data point, not a full health picture
- Recheck your numbers periodically rather than once
- Discuss results with a healthcare provider for context
Common mistakes
- Mixing metric height with imperial weight
- Entering height in meters instead of centimeters
- Treating BMI as a diagnosis rather than a screening ratio
- Ignoring that BMI does not distinguish muscle from fat
Privacy
Your height and weight are processed entirely in your browser using local JavaScript. BMI Calculator does not upload or store this information on any server.
Frequently asked questions
- How is BMI calculated?
- Metric BMI is weight in kilograms divided by height in meters squared. Imperial BMI multiplies weight in pounds by 703, then divides by height in inches squared.
- What do the BMI categories mean?
- Using the standard WHO ranges: under 18.5 is underweight, 18.5–24.9 is normal weight, 25–29.9 is overweight, and 30 or above is obese.
- Is BMI a medical diagnosis?
- No. BMI is a simple screening ratio based only on height and weight. It does not account for muscle mass, bone density, age, or body composition, so it is not medical advice.
- Can I switch between metric and imperial units?
- Yes. Choose metric for kilograms and centimeters, or imperial for pounds and inches. The formula and category thresholds adjust automatically.
- Does BMI Calculator store or upload my measurements?
- No. The calculation happens locally in your browser. Your weight and height are never sent to a server.
- Should I use BMI alone to judge my health?
- No. BMI is one general indicator. Speak with a qualified healthcare provider for a full assessment that considers body composition and other health factors.
Related tools
Statistics Calculator
math
Count, mean, median, mode, and stdev from a list.
- statistics
- mean
- median
- calculator
Age Calculator
math
Age in years, months, and days between two dates.
- age
- date
- calculator
- math
Percentage Calculator
math
Percent of, percent-of-total, and percent change.
- percentage
- percent-change
- calculator
- math
Aspect Ratio Calculator
math
Simplify a ratio and scale to a target dimension.
- aspect-ratio
- resize
- calculator
- math
GPA Calculator
math
Weighted 4.0-scale GPA from grades and credits.
- gpa
- grades
- calculator
- education
Prime Number Checker
math
Check primality and list primes up to a limit.
- prime
- number-theory
- calculator
- math