BMI & Healthy Weight Calculator
Adult weight screening
Enter age, weight, and height
Result
Calculation summary
Enter values to see the result
BMI preview
Healthy-weight reference for your height
Current body weight
70 kg
Healthy-weight reference at this height
56.7–76.3 kg
Current weight compared with the reference interval
The marker follows valid weight and height inputs immediately.
- Below reference< 56.7 kg
- BMI reference interval56.7–76.3 kg
- Above reference> 76.3 kg
Current weight is inside the BMI-based reference interval
This interval is produced only from BMI 18.5 to 24.9 at the entered height; it is not a personalized target.
How to use this calculator
- 1Enter an adult age, body weight, height, and the matching units.
- 2Calculate BMI and review the corresponding adult screening category.
- 3Use the healthy-weight interval only as a BMI-based reference and consider individual context with a qualified professional.
Formula
BMI = weight (kg) ÷ height² (m²)
The healthy-weight interval reverses the same equation at BMI 18.5 and 24.9 for the entered height.
Calculation steps
- Convert weight to kilograms and height to meters.
- Divide weight by squared height and apply adult BMI category boundaries.
- Multiply squared height by 18.5 and 24.9 to calculate the reference weight interval.
Worked example
At 70 kg and 175 cm, BMI is about 22.9. The BMI-based healthy-weight interval is approximately 56.7 to 76.3 kg.
Assumptions
- The standard adult categories are used for people age 20 or older.
- Weight and height are measured accurately without unit confusion.
- BMI does not directly measure body fat, muscle mass, fat distribution, or metabolic health.
- Pregnancy, edema, amputation, athletic muscularity, and individual clinical factors may require a different interpretation.
Sources
Frequently asked questions
Is BMI a diagnosis?
No. BMI is a screening measure that should be interpreted with medical history, body composition, examination findings, and other relevant factors.
Why does the calculator require age 20 or older?
Children and teens use age- and sex-specific BMI percentiles rather than the fixed adult categories used here.
Is every weight inside the displayed range ideal for me?
No. It is only the interval produced by BMI 18.5 through 24.9 at the entered height, not a personalized target.
Can muscular adults have a high BMI?
Yes. BMI cannot distinguish muscle from fat, so muscularity and other individual factors can change how the number should be interpreted.