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BMI Calculator

Calculate your BMI from your height and weight in seconds. The BMI calculator uses US units by default, feet, inches and pounds, and shows your body mass index category plus the healthy weight range for your height. The result updates live as you type, and you can switch to metric anytime.

Built & reviewed by the TurboTeamTools team · Updated September 2026 · 0 uses on this device

BMI Calculator tool

Your BMI
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BMI categories (adults)

CategoryBMI range
UnderweightBelow 18.5
Healthy weight18.5 – 24.9
Overweight25.0 – 29.9
Obesity30.0 and above

How to use it

  1. Choose US units or metric.
  2. Enter your height and weight.
  3. Read your BMI, category and healthy weight range below.

What is body mass index?

Body mass index, or BMI, is a screening number that compares your weight to your height. In US units the formula multiplies weight by 703 and divides by height in inches squared:

BMI = 703 × weight (lb) ÷ height (in)²

Someone who is 5 ft 9 in, which is 69 inches, and weighs 160 lb works out to 703 × 160 ÷ 4,761, or 23.6. In metric, the formula is weight in kilograms divided by height in meters squared, and both versions give the same answer for the same person. Adults with a BMI between 18.5 and 24.9 fall in the healthy range, and the same cutoffs apply to men and women.

Worked example

Input: 5 ft 9 in, 160 lb
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Result: BMI 23.6, healthy weight

Healthy weight range by height

HeightHealthy weight (BMI 18.5 to 24.9)
5 ft 0 in95 to 128 lb
5 ft 2 in101 to 136 lb
5 ft 4 in108 to 145 lb
5 ft 6 in115 to 154 lb
5 ft 8 in122 to 164 lb
5 ft 10 in129 to 174 lb
6 ft 0 in136 to 184 lb
6 ft 2 in144 to 194 lb

Ranges are rounded to the nearest pound. Enter your own height above for an exact figure.

What BMI tells you, and what it misses

Body mass index compares your weight to your height with one number. In US units the formula is 703 × weight in pounds ÷ height in inches squared. Someone who is 5 ft 9 in (69 inches) and 160 lb works out to 703 × 160 ÷ 4,761, which is 23.6. In metric it is weight in kilograms divided by height in meters squared, so 72 kg at 1.75 m is 72 ÷ 3.0625, or 23.5. The 703 is simply the factor that turns pounds and inches into kilograms and meters; both versions give the same answer for the same person.

Adults are sorted into four categories: under 18.5 is underweight, 18.5 to 24.9 is the healthy range, 25 to 29.9 is overweight, and 30 or above is obesity, which is sometimes split further into class 1 (30 to 34.9), class 2 (35 to 39.9) and class 3 (40 and up). The healthy weight line under your result is the same formula run backwards. For a 69-inch person, a BMI of 18.5 corresponds to about 125 pounds and 24.9 to about 169 pounds.

Why BMI is a screening number, not a verdict

BMI does not know the difference between muscle and fat, and it does not account for age, sex, bone structure or where you carry weight. A muscular athlete can read as overweight, an older adult can sit in the healthy range while carrying little muscle, and two people with the same BMI can have very different health. Some health organizations also recommend lower cutoffs for people of Asian descent, with 23 rather than 25 as the start of the overweight range.

Treat the number as a starting point. Doctors pair it with waist circumference, blood pressure, blood sugar and cholesterol before drawing any conclusion, and the categories were built for population studies rather than for judging one person. If your result lands outside the healthy range, or simply surprises you, that is a reason for a conversation with a clinician, not a diagnosis on its own.

Common uses

  • A quick weight-and-height screening
  • Tracking changes over time
  • Estimating a healthy weight range for your height
  • Comparing against standard categories
  • Converting a metric BMI reading to US units
  • Preparing numbers before a doctor's visit

When to use it

  • You want to see what a healthy weight for 5 ft 9 looks like before setting a fitness goal.
  • A doctor's form asks for your body mass index and you only know your height in feet and weight in pounds.
  • You are tracking a weight change and want to know when your BMI crosses from overweight into the healthy range.
  • A metric health report lists a BMI of 27 and you want to see what it means in pounds for your height.

Related tools

The Weight Converter switches your weight between pounds and kilograms before you enter it here.

The Length Converter turns a height in centimeters into feet and inches, or back.

The Age Calculator covers the other number every health form asks for.

Frequently asked questions

Multiply your weight in pounds by 703, then divide by your height in inches squared. For 160 lb at 69 inches, that is 160 times 703 divided by 4,761, which is about 23.6.
Convert your height to meters, square it, and divide your weight in kilograms by that number. At 175 cm and 72 kg, 1.75 squared is 3.0625, and 72 ÷ 3.0625 is 23.5. Switch the calculator to metric to enter centimeters and kilograms directly.
For most adults a BMI between 18.5 and 24.9 is considered healthy. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is in the obesity range.
No. Adults use the same formula and the same category cutoffs regardless of sex. Women tend to carry more body fat than men at the same BMI, which is one reason the number is only a screen. Children and teens do use separate charts for boys and girls.
Not always. Muscle is denser than fat, so very muscular people can have a high BMI while carrying little body fat. BMI is a general screen, not a body-composition measurement. Athletes are better served by a body fat estimate or waist measurement alongside the number.
This calculator uses adult categories. Children and teens are assessed with age and sex percentiles, so use a pediatric BMI chart for anyone under 20. On those charts, the 85th to 94th percentile is considered overweight and the 95th and above is obesity.
Rearrange the formula: weight in pounds = BMI × height in inches squared ÷ 703. For someone 5 ft 9 in, the 18.5 to 24.9 range covers about 125 to 169 pounds. The calculator prints this range under your result, and it is a range, not a single target.
Because the original BMI formula uses kilograms and meters. One pound is 0.45359237 kg and one inch is 0.0254 m, and 0.45359237 divided by 0.0254 squared is 703.07. Multiplying by 703 converts a pounds-and-inches calculation into the metric result.