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BMI Calculator

Additional Metrics

  • Ideal Weight --
  • Weight to Gain/Lose --
  • Daily Calorie Needs --
  • Waist-to-Hip Ratio --

Your BMI

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Calculate Body Mass Index from Height and Weight

This BMI calculator divides weight by height squared and displays the result to one decimal place with an adult-style weight category. BMI is a general screening measure. It does not measure body fat directly, diagnose a condition, or describe a person’s overall health.

CalcMaster BMI Calculator online free
CalcMaster BMI Calculator Online Free

BMI Formula

The calculator accepts metric inputs and uses:

BMI = weight in kilograms / (height in metres)2

Although height is entered in centimetres, the calculator converts it to metres before applying the formula.

Inputs and Additional Estimates

  • Height and weight: determine BMI and its displayed category.
  • Age and gender: do not change BMI, but they affect the separate calorie and ideal-weight estimates.
  • Ideal weight: uses a gender-based Devine formula estimate.
  • Daily calories: uses a Mifflin-St Jeor BMR estimate multiplied by a sedentary factor of 1.2.

The visible waist-to-hip field is not calculated because the form has no waist or hip inputs.

Worked BMI Example

For a weight of 72.5 kg and height of 178 cm:

BMI = 72.5 / 1.782 = 22.9 after rounding.

The calculator labels this result Normal weight because it is between 18.5 and 24.9. This label is a screening category, not a medical conclusion.

How the Calculator Categorizes Results

  • Below 18.5: Underweight
  • 18.5 to 24.9: Normal weight
  • 25.0 to 29.9: Overweight
  • 30.0 to 34.9: Obesity I
  • 35.0 to 39.9: Obesity II
  • 40.0 or above: Obesity III

Assumptions and Health Limitations

The code applies the same adult-style BMI thresholds at every entered age. It does not calculate age- and sex-specific child percentiles and should not be used to assess children or teenagers. BMI can also be misleading during pregnancy and for athletes, older adults, or people whose muscle mass or body composition differs from population averages.

Use the result for general information only. A healthcare professional can interpret weight, growth, symptoms, medical history, and other measurements in context.

Common BMI Mistakes

  • Entering metres or feet where the form expects centimetres.
  • Treating a BMI category as a diagnosis.
  • Assuming BMI directly measures body-fat percentage.
  • Using the adult categories for a child or teenager.

Related Calculators

FAQs

For most adults, a BMI between 18.5 and 24.9 is considered healthy.

No, BMI is just one of many tools. For a full picture of your health, consider also tracking body fat %, waist-to-hip ratio, activity levels, and diet habits.

If you're working on weight management or fitness goals, checking your BMI once every few weeks or monthly can help track progress. Otherwise, checking occasionally is enough for general awareness.

While BMI is a reliable general indicator of weight-related health risks, it doesn’t account for muscle mass or fat distribution. For better accuracy, pair it with a body fat percentage calculator.

No, you don't need to sign up. Our BMI calculator online is completely free to use, with no login or registration required.

Absolutely! Our BMI calculator is optimized for Indian users, but it also works globally. Whether you're calculating BMI in India, the US, or elsewhere, the results remain consistent.

Yes, the BMI formula is the same for both men and women. However, body composition (like muscle mass or fat percentage) can vary, so additional tools like a body fat calculator can offer more insights.

BMI is a useful screening tool, but it does not directly assess body fat or health. Athletes and those with high muscle mass may have a higher BMI but not excess fat.

Improving BMI involves a combination of healthy eating, regular physical activity, and lifestyle changes. Consult a healthcare provider for personalized advice.