Updated October 9, 2026
BMI Calculator
Enter your height and weight, in metric or imperial units, to get your body mass index instantly, along with your weight category and the healthy range for your height.
For general information only. BMI is a screening tool, not medical advice.
What this calculator does
This BMI calculator computes your body mass index from your height and weight, shows which standard weight category you fall into, and gives the healthy weight range for your height. It accepts metric (cm, kg) and imperial (feet/inches, pounds) inputs. For general information only: this is not medical advice.
How the math works
- Metric: BMI = weight (kg) ÷ height (m)2
- Imperial: BMI = 703 × weight (lb) ÷ height (in)2
- Categories (WHO): under 18.5 underweight, 18.5 to 24.9 healthy, 25 to 29.9 overweight, 30 and above obesity.
- Healthy range: 18.5 × height2 to 24.9 × height2, in your chosen units.
Worked example
At 175 cm and 75 kg: BMI = 75 ÷ 1.752 = 24.5, which falls in the healthy range (18.5 to 24.9). The healthy range for 175 cm is 18.5 × 1.752 to 24.9 × 1.752 = 56.7 to 76.3 kg.
What BMI does and does not tell you
BMI is a population screening tool: cheap, fast, and correlated with health risks across large groups. It does not measure body fat, muscle, bone density or where fat is carried. Muscular athletes can score "overweight" while being very lean, and older adults can have a "healthy" BMI with too little muscle. Waist circumference and trends over time add useful context.
Limitations
BMI was designed for populations, not individuals, and the cutoffs are less reliable for athletes, pregnant people, children and teenagers (who use percentile charts), and some ethnic groups. Treat the result as one data point. If your BMI is high and you are concerned, talk to a clinician rather than acting on a number alone. This content is general information, not medical advice.
Planning estimate only. Results use the list prices shown and may differ from your actual bill. Terms
Frequently asked questions
What is a good BMI?
The World Health Organization defines 18.5 to 24.9 as the healthy range for adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obesity. These are screening cutoffs, not diagnoses.
Is BMI accurate for athletes?
Not always. BMI cannot tell muscle from fat, so muscular athletes often land in the overweight or obese ranges despite low body fat. Body fat percentage, waist measurements or a professional assessment are better tools for them.
How is BMI calculated in imperial units?
BMI = 703 × weight in pounds ÷ (height in inches)². For example, 165 lb at 69 inches: 703 × 165 ÷ 69² = 24.4. The 703 is just the conversion factor that makes imperial units match the metric formula.
What should I do if my BMI is high?
Treat it as a prompt to look closer, not a verdict. Consider waist circumference, blood pressure, activity and diet, and talk to a clinician about your overall risk. Sustainable habits beat crash diets for moving the number safely.
Do men and women use the same BMI ranges?
Yes, the adult BMI cutoffs are the same for men and women. Children and teenagers use separate age- and sex-specific percentile charts instead.
Is my data sent anywhere?
No. The calculator runs entirely in your browser. Nothing you enter is uploaded or stored.