Category: Calculators
BMI Calculator
Calculate adult body mass index and a fixed BMI category
Calculate adult BMI from metric or imperial height and weight, with fixed adult categories. Runs locally, with no upload, diagnosis or weight-loss advice.
Everything on this page is processed in your browser. Nothing is uploaded.
What this tool does
This BMI calculator computes body mass index from height and weight. In metric mode it uses height in centimetres and weight in kilograms, dividing weight by height in metres squared. In imperial mode it uses height in inches and weight in pounds with the standard 703 conversion factor. The result is shown to one decimal place with trailing zeros trimmed and classified with fixed adult thresholds: underweight below 18.5, normal from 18.5 to below 25, overweight from 25 to below 30, and obesity at 30 and above. The tool does not adjust for age, sex, ethnicity, pregnancy, athletic build or high muscle mass. It does not provide child or teen BMI-for-age percentiles, obesity class I/II/III subdivisions, body-fat percentage, waist-to-height ratio, lean mass, BMR, TDEE, ideal weight or calorie calculations. BMI is a screening number, not a diagnosis or health assessment, and LocalTools does not provide medical, diet, treatment, weight-loss or eligibility advice. Height, weight and results stay in the browser and are not uploaded to LocalTools.
How to use it
- Choose metric or imperial units and enter height and weight.
- Read the BMI value to one decimal place and the matching fixed adult category.
- Use it only as a screening number; diagnosis, child percentiles and individualized health advice are out of scope.
Privacy
This tool runs entirely in your browser. Your input is never uploaded, stored or shared — closing the tab removes it.
Frequently asked questions
- How is BMI calculated?
- Metric BMI divides kilograms by height in metres squared. Imperial BMI uses pounds and inches with the 703 conversion factor.
- Which BMI categories does it show?
- It uses fixed adult categories: underweight below 18.5, normal from 18.5 to below 25, overweight from 25 to below 30, and obesity at 30 or above.
- Is BMI a diagnosis?
- No. BMI is a screening measure, not a medical diagnosis or treatment plan. Use clinical guidance for health decisions.
- Can adult BMI categories be used for children?
- No. This tool does not calculate BMI-for-age percentiles for children or teenagers.
- Are my height and weight uploaded?
- No. The calculation runs in your browser, and LocalTools does not receive or store your height, weight or result.