Adult BMI & Weight Change Calculator
Calculate your adult BMI and explore how your weight has changed over time. BMI is a screening measure—not a diagnosis, treatment recommendation, or complete measure of health.
This calculator is intended for adults age 20 and older. BMI for children and teenagers is evaluated using age- and sex-specific growth charts.
Calculate Current BMI
Enter a height greater than zero.
Enter a weight greater than zero.
Explore Weight Change
All fields below are optional. Current weight carries over from the BMI section above.
Carried from BMI section
Optional personal goal
Optional personal goal — not a medical recommendation.
Your entered weight history
Add optional weight entries to see changes over time. Entries stay in your browser session and are not saved unless you choose to save them.
No entries yet. Add a date and weight above to start tracking.
What BMI does not measure
BMI does not directly measure body fat and does not distinguish fat from muscle, bone, or other body tissue. It does not show where body fat is carried and does not account for fitness, medical history, laboratory results, or individual differences.
The relationship between BMI and health risk may differ based on factors including age, sex, muscle mass, body composition, and racial or ethnic background.
BMI should not be used by itself to diagnose a health condition or determine whether a medication or treatment is appropriate.
When BMI may need additional context
BMI may be less informative when evaluating:
- Highly muscular individuals
- Older adults with reduced muscle mass
- Pregnancy
- People with significant fluid retention
- Children and teenagers
- Individuals whose body composition differs substantially from population averages
Discuss the meaning of your BMI with a qualified healthcare professional when these or other individual circumstances apply.
Other information a healthcare professional may consider
BMI is one of many measurements. A healthcare professional may also consider:
This calculator does not ask you to enter these measurements and does not generate cardiovascular, diabetes, metabolic, or mortality risk scores.
Related educational resources
Disclaimer
This calculator provides general educational information and mathematical estimates. BMI is a screening measure and is not a diagnosis, medical recommendation, or complete assessment of health. Consult a qualified healthcare professional for interpretation based on your individual circumstances.
