BMI Calculator
Calculate your BMI in seconds — see your category, chart position, and healthy weight range
About this BMI calculator
Enter your weight and height for an instant body mass index (BMI). Optionally add sex and age for plain-language context—your BMI number itself follows the standard formula either way. This matches what people search for when they look for a BMI calculator with age or BMI for women / male BMI guidance alongside the same index.
You will see your category (underweight, healthy, overweight, or obesity class), a color-coded scale, and the healthy weight range for your height. Always confirm personal decisions with a qualified professional.
Calculate your BMI
Adult categories apply to ages 18+. For children, use growth charts.
Your BMI
22.7
Healthy weight (18.5 – 24.9)
Your position on the adult BMI scale
Healthy BMI range for your height
For your height, a BMI between 18.5 and 24.9 usually corresponds to roughly 125–169 lb. This is an estimate for screening, not a prescription.
BMI visual chart
Height and weight axes (imperial). Colored bands show BMI categories; the dot uses your current calculator inputs.
At 5'9" and 154 lbs, BMI is 22.7. Chart area: about 4'10"–6'6" height and 80–350 lbs; if you are outside that range, the dot sits on the nearest edge.
What to do next (general ideas)
- Maintain balanced meals, regular movement, and sleep.
- Track trends over months, not days.
BMI chart & categories
Body Mass Index (BMI) relates height and weight. The table below shows standard adult BMI categories used for screening (CDC / WHO).
| BMI range | Classification | Notes |
|---|---|---|
| Below 18.5 | Underweight | May need clinical evaluation depending on symptoms. |
| 18.5 – 24.9 | Healthy weight | Typical screening target range for adults. |
| 25.0 – 29.9 | Overweight | Elevated risk at population level; context matters. |
| 30.0 – 34.9 | Obesity class I | Discuss risk factors and options with a provider. |
| 35.0 – 39.9 | Obesity class II | Higher average health risk; individualized care helps. |
| 40.0 and above | Obesity class III | Often managed with multidisciplinary support. |
These BMI categories reflect broad health-risk patterns across populations. BMI is a screening tool, not a diagnosis—your individual health depends on many factors beyond BMI.
BMI for women vs men
While the BMI scale is the same for both sexes, women and men can have the same BMI but different body composition and health implications.
Women
- Typically have 6–11% more body fat than men
- Healthy range: 18.5–24.9 (same scale)
- Higher body fat percentage can be normal and healthy
- Hormones affect weight distribution
- Pregnancy and menopause impact BMI
- Often carry weight in hips and thighs
Men
- Generally have more muscle mass
- Healthy range: 18.5–24.9 (same scale)
- Muscle weighs more than fat (BMI may underestimate fitness)
- Lower body fat percentage at the same BMI
- Testosterone influences body composition
- Often carry weight in the abdomen
Women with the same BMI as men typically have a higher body fat percentage, but that can be normal and healthy. Standard BMI ranges account for typical differences in body composition.
How BMI changes with age
While official BMI ranges (18.5–24.9 = healthy) stay the same regardless of age, research shows that slightly higher BMI may be acceptable—and even protective—as we get older.
Age-based BMI observations
| Age group | Ideal BMI range* | Notes |
|---|---|---|
| 19–24 years | 19–24 | Lower range often optimal for young adults |
| 25–34 years | 20–25 | Slight increase from early 20s |
| 35–44 years | 21–26 | Metabolism begins to slow |
| 45–54 years | 22–27 | Muscle mass naturally decreases |
| 55–64 years | 23–28 | Slight increase may be protective |
| 65+ years | 24–29 | Higher BMI sometimes linked to better outcomes in studies |
These are research-based observations, not official guidelines. The standard healthy range (18.5–24.9) still applies to all adults for screening. Always consult your doctor about your individual goals.
Why BMI trends higher with age
- Muscle loss: adults may lose 3–8% of muscle mass per decade after age 30
- Metabolism slows: basal metabolic rate decreases about 2% per decade
- Hormonal changes: reduced testosterone (men) and estrogen (women) affect body composition
- Protective effect: some studies suggest slightly higher BMI (25–27) in seniors may protect against illness and frailty
Healthy BMI range
For most adults, a healthy BMI falls between 18.5 and 24.9. This band is associated with lower average risk of several chronic diseases at the population level than higher BMI bands. Your optimal target may still differ based on muscle mass, ethnicity-related risk (for example, some Asian populations use lower action thresholds), and medical history—use this page as education, not a diagnosis.
What does your specific BMI mean?
Search for your BMI value to see what it often means for screening. These are general patterns, not personal medical advice.
We highlight common search values. Your BMI falls on a continuum—use the category table above and your clinician for personalized interpretation.
When BMI doesn’t tell the full story
BMI is a useful screening tool, but it has important limits. Here is when BMI may not reflect your health status accurately.
BMI limitations
- Muscle vs fat: athletes may have a high BMI with low body fat.
- Bone density: denser bones can raise BMI without indicating poor health.
- Fat distribution: belly fat is riskier than hip/thigh fat, but BMI treats weight the same everywhere.
- Ethnicity: some groups face higher risk at lower BMI (for example, many Asian guidelines use action thresholds above 23).
- Older adults: muscle loss can make BMI look "healthy" while body composition worsens.
- Children: use pediatric BMI percentiles—not adult cutoffs.
- Pregnancy: BMI categories are not meant for pregnancy or the immediate postpartum period the same way.
Better alternatives or additions
- Waist circumference: belly fat indicator; common risk flags include roughly 40" (men) and 35" (women), per many clinical references.
- Waist-to-hip ratio: compares fat distribution.
- Waist-to-height ratio: waist should often be under half your height—simple rule of thumb used in some guidelines.
- Body fat percentage: calipers, bioimpedance, or DXA—each has tradeoffs.
- Labs and vitals: glucose, lipids, and blood pressure often matter as much as weight alone.
When to use alternatives
Use BMI for
- ✓Quick screening
- ✓Population trends
- ✓Tracking changes over time (with context)
- ✓Typical adults without unusual muscle mass
Favor add-on measures for
- ✓Athletes and bodybuilders
- ✓Many older adults
- ✓Pregnancy or postpartum (clinician-guided)
- ✓Children and teens
- ✓Anyone wanting a direct body-fat estimate
On Help Calculate you can also try:
BMI calculator FAQ
Formula and manual calculation
Metric steps
- Measure weight in kilograms.
- Measure height in meters (centimeters ÷ 100).
- Square height (m × m).
- Divide weight by squared height.
Imperial steps
- Measure weight in pounds.
- Measure height in total inches.
- Square height in inches.
- Multiply weight by 703, divide by squared height.
Trusted references
🎉 Fun Facts
- •The modern BMI formula dates to the 1830s (Lambert Adolphe Jacques Quetelet). It was meant to describe populations—not to label individuals as healthy or not.
- •Muscle weighs more than fat per volume. Athletes and very muscular people can have a high BMI without high body fat—so BMI is screening, not diagnosis.
- •Health risk at a given BMI varies by ancestry, waist size, and other factors. Some guidelines use lower action thresholds for Asian populations than for European populations.
- •For people under 18, BMI is interpreted with age- and sex-specific growth charts (for example CDC charts)—not the adult categories this calculator uses.