BMI Calculator

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Height
cm ft
cm ft
in
Weight
kg lb
kg lb
Male Female
kg/m²
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18.5
25
30
35
Underweight Normal Overweight Obese
Current
Ideal Range
Difference
Enter your measurements for personalized insights

Making Sense of Your BMI Results

BMI serves as a screening tool rather than a diagnostic measure. The results from our calculator provide a starting point for understanding your weight status, but interpreting these numbers properly requires additional context.

BMI Categories and Their Implications

BMI Value
Classification
Health Considerations
Below 18.5
Underweight
Potential nutritional deficiencies, reduced immune function
18.5 – 24.9
Normal
Generally associated with optimal health outcomes
25.0 – 29.9
Overweight
Increased risk for heart disease, diabetes, hypertension
30.0 – 34.9
Obese Class I
Moderate to high risk of weight-related health problems
35.0 – 39.9
Obese Class II
High risk of developing serious health conditions
40.0+
Obese Class III
Very high risk requiring comprehensive medical attention

Getting More Accurate Results

  • Measure your height accurately – Stand against a wall without shoes, keep your head level and eyes forward
  • Weigh yourself consistently – Same time of day, similar clothing, same scale
  • Use multiple measurements – Track your BMI over time rather than relying on a single calculation
  • Enter precise values – Small measurement errors can impact results, especially at boundary values

When BMI Doesn’t Tell the Full Story

BMI calculations have several notable limitations:

Body Composition Not Considered

BMI doesn’t distinguish between muscle and fat. Athletes with high muscle mass often register as “overweight” despite having low body fat percentages.

Age and Gender Differences

Men typically have higher muscle mass than women of the same BMI. Older adults naturally experience changes in body composition that BMI doesn’t account for.

Ethnic Variations

Different ethnic groups may have different body compositions at the same BMI. For example, Asian populations often have higher body fat percentages at lower BMIs.

Fat Distribution Patterns

Where you carry weight matters significantly. Central obesity (belly fat) poses greater health risks than fat distributed in other areas.

Better Metrics to Use With BMI

Waist Circumference

Measures abdominal fat, which is linked to higher disease risk.

High Risk Thresholds:
Women: > 35 inches (88 cm)
Men: > 40 inches (102 cm)

Waist-to-Height Ratio

Divides waist measurement by height. Simple yet effective predictor of health risks.

Target: Keep your waist circumference to less than half your height.

Body Fat Percentage

Directly measures fat versus lean mass using methods like bioelectrical impedance.

Healthy Ranges:
Women: 21-33%
Men: 8-19%

Practical Next Steps Based on Your BMI

If Your BMI is Below 18.5

  • Ensure adequate caloric intake with nutrient-dense foods
  • Consider tracking your daily calories to ensure you’re meeting needs
  • Add strength training to build muscle mass
  • Consult a healthcare provider if weight gain is difficult

If Your BMI is 18.5-24.9

  • Maintain your current healthy habits
  • Focus on regular physical activity (150+ minutes/week)
  • Continue balanced nutrition with appropriate portion sizes
  • Consider other health metrics beyond weight

If Your BMI is 25-29.9

  • Aim for modest weight loss (5-10% of body weight)
  • Increase physical activity gradually
  • Create a small calorie deficit (250-500 calories/day)
  • Measure waist circumference to assess central fat

If Your BMI is 30+

  • Consult healthcare providers for personalized guidance
  • Set realistic, gradual weight loss goals
  • Consider professional support (dietitian, physician, etc.)
  • Monitor other health markers (blood pressure, blood sugar, etc.)