Enter your details
Use adult values only. Pregnancy mode requires pre-pregnancy weight.
Calculation history
| Date | BMI | Category | Mode |
|---|---|---|---|
| No saved calculations yet. | |||
What BMI means
BMI compares body weight with height. It offers a quick screening estimate. It cannot diagnose health or body composition alone.
Women and men use the same adult formula. Individual body composition can still differ considerably. Use results alongside professional health assessment when appropriate.
Formula used
Metric BMI divides kilograms by squared metres. Imperial BMI multiplies pounds by 703 first. Both methods produce equivalent BMI values when converted.
| System | Formula |
|---|---|
| Metric | BMI = kg ÷ m² |
| Imperial | BMI = 703 × lb ÷ in² |
How to use this calculator
Select a calculation mode first. Choose metric or imperial measurements next. Enter valid adult details before calculating your result.
Pregnancy mode requires pre-pregnancy weight. Target mode compares current and goal weights. Reverse mode finds weight from a selected BMI.
Adult BMI categories
| BMI | Classification |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Healthy weight |
| 25.0–29.9 | Overweight |
| 30.0–34.9 | Obesity Class 1 |
| 35.0–39.9 | Obesity Class 2 |
| 40.0 or higher | Obesity Class 3 |
Example calculations
| Height | Weight | BMI | Result |
|---|---|---|---|
| 160 cm | 50 kg | 19.5 | Healthy weight |
| 165 cm | 68 kg | 25.0 | Overweight |
| 170 cm | 82 kg | 28.4 | Overweight |
| 175 cm | 98 kg | 32.0 | Obesity Class 1 |
Women-specific considerations
BMI does not measure body-fat percentage. Hormonal stages can influence body composition. Waist context may provide additional useful information.
Athletes may carry more lean mass. Older adults may lose muscle over time. Personal medical assessment offers more complete health context.
Pregnancy and BMI
Pregnancy changes body weight naturally. Standard current-weight BMI becomes less informative. Use pre-pregnancy weight for contextual screening instead.
Do not begin rapid weight loss during pregnancy. Individual needs vary across pregnancy stages. Discuss changes with qualified maternity professionals promptly.
Frequently asked questions
Does women’s BMI use another formula?
No separate adult female formula is required. The calculation uses weight and squared height. Interpretation still depends on personal health context.
Can this calculator diagnose a condition?
No, BMI is only a screening measure. It cannot diagnose disease or body composition. Seek professional assessment for individual medical concerns.
Can pregnant women use standard BMI?
Current pregnancy weight should not receive standard interpretation. Use pre-pregnancy weight for contextual guidance. Discuss weight changes with maternity professionals.
What is a healthy adult BMI?
The standard healthy range is 18.5 through 24.9. It remains a broad population screening range. Personal needs can differ from category labels.
Why include waist circumference?
Waist size adds information about fat distribution. It does not change the BMI calculation. Measure consistently for useful comparisons over time.
Is BMI accurate for athletes?
BMI may classify muscular people at higher levels. It cannot separate muscle from body fat. Consider additional body-composition measurements when needed.
Can teenagers use this calculator?
This calculator is designed for adults only. Younger users require age-adjusted growth references. Use a dedicated child BMI assessment instead.
What does reverse BMI calculate?
Reverse mode finds weight for selected BMI. It uses your entered height measurement. The result does not create a medical target.
Should I choose a target weight?
Targets should remain realistic and sustainable. Health depends on more than weight alone. Professional advice may support safer individual planning.
Medical disclaimer
This calculator provides general educational information only. It does not replace medical assessment. Contact a qualified professional for personal guidance.
Seek urgent care for serious symptoms. Avoid rapid or unsafe weight changes. Pregnancy and eating concerns need sensitive professional support.