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BMI Calculator

Calculate BMI from height and weight. See category, healthy weight range, BMI Prime, Ponderal Index, and step by step math.

US & Metric Adult & Child WHO categories
BMI value Category Healthy weight range BMI Prime Ponderal Index Calculation steps
yrs
ft
in
lbs
Optional - for deeper insights
in
in
in
Your Body Mass Index
22.96
โœ… Normal Weight
WHO adult BMI categories
BMI Prime
0.918
Ponderal Index
12.9 kg/mยณ
Your calculation
BMI = 72.57 รท (1.778 ร— 1.778) BMI = 72.57 รท 3.1613 BMI = 22.96
Category: Normal Weight. Healthy weight range at this height: 128.9 lb โ€“ 173.5 lb.
Inputs used
5'10" ยท 160 lb
Metric equivalent
72.6 kg ยท 177.8 cm
BMI Prime
0.918 (BMI รท 25)
Ponderal Index
12.91 kg/mยณ
BMI 22.96 kg/mยฒ is classified as Normal Weight using WHO adult cutoffs. A healthy weight range for this height is about 128.9 lb โ€“ 173.5 lb. BMI is a screening result, not a diagnosis.
๐Ÿ“ BMI Scale
โ‰ค16
18.5
25
30
35
40+
Healthy Weight Range
128.9 lb โ€“ 173.5 lb
58.5 โ€“ 78.7 kg
Weight to Lose / Gain
Within healthy range for this height
BMI Category
Normal Weight
WHO Standard
Child Percentile
Adult (N/A)
Age and sex based
๐ŸŽฏ Your healthy weight range at your height
BMI Normal range
128.9 lb โ€“ 173.5 lb
Overweight starts
174.2 lb+
Obese starts
209.0 lb+
BMI Prime
0.918 (โ‰ค 1.0)
Ponderal Index
12.9 kg/mยณ

How BMI Is Calculated

Body Mass Index (BMI) is a screening number that relates weight to height. Health organizations use it to group adults into underweight, normal, overweight, and obesity categories. BMI does not measure body fat, muscle, or health by itself.

Adult BMI uses weight in kilograms divided by height in metres squared:

This calculator converts US or stone inputs to kilograms and metres first, then applies the metric formula so the result matches the WHO unit (kg/mยฒ).

More examples

90 kg at 1.80 m โ†’ 90 รท 1.80ยฒ = 27.78 (Overweight) Healthy range at 1.80 m โ‰ˆ 59.9โ€“80.7 kg 60 kg at 1.65 m โ†’ 60 รท 1.65ยฒ = 22.04 (Normal) Healthy range at 1.65 m โ‰ˆ 50.4โ€“67.8 kg

Adult BMI Categories

WHO adult classifications commonly used for ages 20 and older:

ClassificationBMI (kg/mยฒ)
Underweight< 18.5
Normal18.5 โ€“ 24.9
Overweight25.0 โ€“ 29.9
Obesity class I30.0 โ€“ 34.9
Obesity class II35.0 โ€“ 39.9
Obesity class IIIโ‰ฅ 40.0

The result table above the article can also highlight finer underweight bands (severe, moderate, mild thinness) used in some WHO tables. Asia Pacific cutoffs use a lower overweight threshold (from 23) and obesity from 27.5 when that option is selected.

Healthy weight range

For a given height, the calculator multiplies the normal BMI bounds by heightยฒ:

Min weight = 18.5 ร— heightยฒ  ยท  Max weight = 24.9 ร— heightยฒ Example at 1.75 m: 18.5 ร— 3.0625 to 24.9 ร— 3.0625 โ‰ˆ 56.7 to 76.3 kg Asia Pacific mode uses 18.5 to 22.9 for the normal band instead of 18.5 to 24.9.

BMI Prime

BMI Prime is your BMI divided by 25 (the usual upper end of the adult normal range). Below 1.0 is at or under that reference; above 1.0 is above it.

BMI Prime = BMI รท 25Example: 22.86 รท 25 = 0.91

Ponderal Index

Ponderal Index divides weight by height cubed (kg/mยณ). It scales differently from BMI for very tall or short people. This page reports the Corpulence Index form PI = kg รท mยณ so you can compare it with BMI, not as a replacement for clinical assessment.

PI = weight (kg) รท heightยณ (m)Example: 70 รท 1.75ยณ โ‰ˆ 13.1 kg/mยณ

BMI for Children and Teens (Ages 2โ€“19)

The BMI formula is the same for children, but adult cutoffs must not be used to label a child. CDC guidance classifies children using BMI for age percentiles by sex:

CategoryPercentile
Underweight< 5th
Healthy weight5th to < 85th
Overweight85th to < 95th
Obesityโ‰ฅ 95th
โš ๏ธ
Enter age 2โ€“19 to switch this tool into child mode. The percentile shown is an approximation for education only. It is not a clinical CDC growth chart lookup. Use CDC growth charts or a clinician for medical decisions.

Limitations of BMI

  • BMI does not measure body fat or distinguish muscle from fat.
  • Athletes with high muscle mass may be labeled overweight despite low body fat.
  • BMI does not describe fat location (for example abdominal fat).
  • Age, sex, and ethnicity can change how clinicians interpret a given BMI.
  • BMI is a screening aid, not a diagnosis or a complete health assessment.
๐Ÿ’ก
For a fuller picture, pair BMI with waist size, body composition tools, and clinical measures. Related calculators: BMR, TDEE, Body Fat, Ideal Weight, and Calorie.

Calculation Methodology and Sources

How DoCalculation computes BMI

  1. Convert height and weight to metres and kilograms when needed.
  2. Compute BMI = kg รท mยฒ.
  3. Assign a category using WHO adult cutoffs, or WHO Asia Pacific cutoffs if you select Asian ethnicity.
  4. Compute a healthy weight range for your height using the selected normal BMI band ร— heightยฒ.
  5. Compute BMI Prime = BMI รท 25 and Ponderal Index = kg รท mยณ.
  6. For ages 2 to 19, show an approximate percentile for education only (not a CDC clinical chart).

Sources & References

Results on this page are for information only. They are not medical advice.

Frequently Asked Questions

What is a healthy BMI for adults?
For many adults, WHO treats 18.5 to 24.9 as the normal BMI range. Below 18.5 is underweight. 25.0 to 29.9 is overweight. 30.0 and above is obesity. Some Asian populations use lower action points for overweight and obesity.
How do you calculate BMI?
Divide weight in kilograms by height in metres squared. In US units use BMI = 703 ร— pounds รท inches squared. Example: 70 kg at 1.75 m gives 22.86.
Is BMI different for men and women?
The adult BMI formula and usual WHO cutoffs are the same for men and women. Body fat at a given BMI often differs by sex, so BMI is only one screening input.
How is BMI interpreted for children?
For ages 2 to 19, CDC uses BMI for age percentiles by sex rather than adult cutoffs. Healthy weight is generally the 5th to less than the 85th percentile. This calculatorโ€™s child percentile is approximate and educational only.
What are the limitations of BMI?
BMI does not measure body fat, muscle, or fat location. It can misclassify muscular people and does not replace waist measures, body composition tests, or clinical judgment.
What is BMI Prime?
BMI Prime equals BMI divided by 25. A value of 1.0 matches the usual upper normal adult BMI. Values below 1.0 are at or under that reference.