BMI Calculator
Free online adult BMI calculator — metric kg and cm (or meters) and US lb with feet and inches. Same weight ÷ height² formula used by WHO, CDC adult charts, and NHS pages.
This BMI calculator for men and women estimates body mass index from height and weight. Choose metric (BMI calculator in kg with cm) or US units, then read your number and the WHO adult category. It is a screening tool, not a diagnosis, and not a pediatric CDC BMI-for-age percentile calculator.
Not medical advice and not an official CDC, NHS, NIH/NHLBI, or national health-service tool. Talk to a qualified clinician about your health, especially for children, pregnancy, and eating-disorder risk.
BMI calculator formula
BMI = weight (kg) ÷ height (m)². US: BMI = 703 × weight (lb) ÷ height (in)².
Example (kg and cm): 70 kg at 170 cm → 70 ÷ 1.70² ≈ 24.2. Reverse BMI calculator (ideal weight): weight kg = target BMI × height m². At 1.70 m and BMI 22, weight ≈ 63.6 kg. Lean or “fat” BMI is not a separate formula — muscle and fat need a body-fat estimate.
How to use this BMI calculator
- Choose Metric (kg, cm) or US (lb, ft/in). For a BMI calculator in meters, use metric and enter height in cm (170 cm = 1.70 m).
- Enter your weight. BMI calculator for kg is the metric weight field; US weight is pounds.
- Read BMI (one decimal) and the WHO adult category. Check your BMI against the chart on this page.
- For calories, lose-weight plans, or body fat, use the linked calculators — BMI does not count calories or fat percentage.
About this calculator
What a BMI calculator is: BMI = weight (kg) ÷ height (m)². In US units: BMI = 703 × lb ÷ in². How to work a BMI calculator: pick units, enter weight and height, read the result. Height in meters is cm ÷ 100. A BMI calculator with feet and kg is mixed units — convert feet to meters first (ft × 0.3048), then use kg ÷ m². This page keeps metric and US consistent so you do not mix lb with cm.
BMI calculator without age: the adult number does not use age or gender. BMI calculator on age, by gender and age, or for women with age still computes the same kg/m². Age and sex matter for children and teens (CDC pediatric / KidsHealth-style BMI-for-age percentiles), not for this WHO adult chart. Men’s and women’s adult cut-offs here are the same.
Official-looking searches (CDC adult BMI calculator, NHLBI / National Institutes of Health, NHS / British / UK, AARP, Bupa, MDCalc, calculator.net, American Heart Association) use this same adult formula. This is MeasureZone’s free BMI calculator — not those organizations’ apps. Military, insurance (ICICI), and some Asian cut-offs may interpret the number differently; we show WHO adult categories and note Asia-Pacific alternatives below.
Examples
BMI calculator for kg and cm
70 kg at 170 cm: BMI = 70 ÷ 1.70² ≈ 24.2 (normal weight on the WHO adult chart).
US height and weight
150 lb at 5 ft 7 in (67 in): BMI = 703 × 150 ÷ 67² ≈ 23.5.
Reverse BMI (target weight)
Want BMI 22 at 175 cm (1.75 m): weight = 22 × 1.75² ≈ 67.4 kg.
WHO adult BMI chart
Use this weight BMI calculator chart after you have a number. It is an adult chart, not a kidshealth or CDC pediatric percentile table.
- Underweight: BMI below 18.5
- Normal weight: 18.5 to 24.9
- Overweight: 25.0 to 29.9
- Obesity: 30.0 and above
Age, children, and pregnancy
BMI calculator for pediatric use, childs / childhood BMI, infant BMI, and teens should be BMI-for-age (CDC or WHO growth charts), which need sex and age. This adult calculator will still output a number for a child — do not apply the adult bands to kids.
BMI calculator for pregnant women is not a substitute for obstetric care. Weight gain in pregnancy is assessed differently. Alternative to BMI: waist-to-hip ratio, body-fat estimate, and clinical exam.
kg, countries, and other charts
BMI calculator in India, Pakistan, Malaysia, Singapore, Indonesia, Australia, New Zealand (NZ), Canada, Ireland, UK, South Africa, and Hong Kong uses the same kg and cm (or m) formula. Asian BMI calculator discussions often cite lower overweight/obesity cut-offs (for example 23 and 27.5) used in some Asia-Pacific guidance — interpret with a clinician; this tool still labels WHO international adult categories.
BMI calculator and calories: BMI is not a calorie target. Pair this page with the calorie and BMR calculators if you are planning weight change. Smart / accurate BMI: the arithmetic is exact; the health meaning is not — athletes (“lean BMI”) can score “overweight” with low fat.
FAQ
How to check BMI calculator?+
Enter height and weight above, then compare the result with the WHO adult chart (18.5–24.9 typical “normal”). How to check / how to measure: a home scale and a stadiometer or wall mark; this calculator does the arithmetic.
BMI calculator on age?+
Adult BMI does not include age. BMI calculator on age for children and teens is BMI-for-age (CDC pediatric percentiles by sex). This page is an adults BMI calculator without an age field.
How to measure BMI calculator?+
Measure weight, measure height, then apply the formula. Metric: kg and cm. US: lb and inches (feet × 12 + leftover inches). How to use a BMI calculator: that is the three-step form on this page.
What BMI calculator?+
A BMI calculator is a tool that computes body mass index from height and weight. This online BMI calculator uses the WHO adult formula. It is not a childhood, infant, or pregnancy diagnostic tool.
What's my BMI calculator?+
Use the form: metric 70 kg and 170 cm gives about 24.2. “My BMI calculator” is just this page with your numbers — results stay in your browser.
WHO BMI chart?+
WHO adult categories: underweight < 18.5; normal 18.5–24.9; overweight 25.0–29.9; obesity ≥ 30. CDC adult charts match these bands. Child charts are percentiles, not these adult cut-offs.
Is this an NHS or CDC BMI calculator?+
The formula matches NHS UK, CDC adult, and NIH/NHLBI adult calculators. It is not the official NHS, CDC, or NIH website. Pediatric CDC BMI is a different method.
BMI calculator for women vs men?+
Adult WHO BMI uses the same formula for women and men. Gender does not change kg/m². Pregnancy: do not use standard BMI targets without a clinician. For waist risk, use waist-to-hip ratio rather than BMI alone.