BMI Calculator
Calculate BMI from height and weight. Use it as a screening number, not a full health verdict.
Your BMI
24.4
Category
Normal
BMI Scale
How to use
Choose imperial or metric units, enter height and weight, and calculate. The result shows your BMI category and where the number sits on the standard adult BMI range.
Formula
For imperial units, the formula is BMI = (weight in lbs × 703) / (height in inches)². A BMI below 18.5 is underweight, 18.5-24.9 is normal, 25-29.9 is overweight, and 30+ is obese. BMI is a screening tool, it does not directly measure body fat or account for muscle mass, age, or gender.
When this calculator helps
BMI is useful because it is simple. That is also its biggest flaw. It can flag a possible weight-related risk, but it cannot tell whether the weight is muscle, fat, water, or anything else. Use it as a starting point for a conversation, especially if the number surprises you.
Examples
Example 1: Average Adult Male
A 5'10" man weighing 180 lbs has a BMI of 25.8, placing him in the overweight category. Losing just 10 pounds would bring his BMI down to 24.4, within the normal range. At a 500-calorie daily deficit, this could take roughly 10 weeks.
Example 2: Petite Woman
A 5'2" woman weighing 110 lbs has a BMI of 20.1, which falls squarely in the normal weight category. Her healthy weight range for this height spans roughly 104 to 136 pounds, giving her comfortable margin within the normal BMI band.
Example 3: Muscular Athlete
A 6'0" athlete weighing 220 lbs has a BMI of 29.8, technically overweight. However, with 12% body fat and significant muscle mass, he is in excellent health. This illustrates why BMI should be used alongside other metrics like body fat percentage for active individuals.
Things to watch
- •Weigh yourself at the same time each day, morning after using the bathroom and before eating gives the most consistent reading.
- •BMI does not measure body fat directly. Pair it with waist circumference or a body fat calculator for a more complete picture.
- •A BMI in the normal range does not guarantee good health, factors like blood pressure, cholesterol, and blood sugar matter too.
- •For children and teenagers, use age-specific BMI percentile charts rather than the standard adult BMI categories.
- •Track BMI trends over weeks and months rather than reacting to a single measurement, as daily weight can fluctuate 2-4 lbs from water retention alone.
Sources and methodology
Last reviewed: April 25, 2026. We review formulas, default assumptions, and examples against public references when a formal source applies.
Method: This calculator uses the formula explained on this page, then checks default assumptions and examples against the references listed below.
- •Adult BMI Calculator, Centers for Disease Control and Prevention
- •Calculating BMI, Centers for Disease Control and Prevention
Found something off? Send a correction with the page URL, inputs, result, and expected result.
Common questions
- What is a healthy BMI range?
- A BMI between 18.5 and 24.9 is considered normal weight. Below 18.5 is underweight, 25-29.9 is overweight, and 30 or above is obese. However, BMI doesn't distinguish between muscle and fat, so athletes may have a high BMI despite being healthy.
- Is BMI accurate for everyone?
- BMI is a useful screening tool for populations but has limitations for individuals. It can overestimate body fat in athletes with high muscle mass and underestimate it in elderly individuals who have lost muscle. It also doesn't account for body fat distribution, which matters for health risk.
- How do I calculate my BMI?
- BMI is calculated by dividing your weight in kilograms by your height in meters squared: BMI = kg/m². In imperial units, multiply your weight in pounds by 703, then divide by your height in inches squared. For example, a 150-pound person who is 5'7" has a BMI of 23.5.
- Does BMI differ by age or gender?
- Standard adult BMI categories apply to anyone 20 and older regardless of gender. For children and teens aged 2-19, BMI is plotted on age- and sex-specific growth charts and expressed as a percentile. A child at the 85th-95th percentile is considered overweight, and above the 95th percentile is obese.
- What should I do if my BMI is too high or too low?
- If your BMI falls outside the normal range of 18.5-24.9, consult a healthcare provider before making major changes. For high BMI, a modest calorie deficit of 500 calories per day can lead to about 1 pound of weight loss per week. For low BMI, focus on calorie-dense nutrient-rich foods and strength training to build lean mass.