# BMI Calculator > Free BMI calculator with metric and imperial units, plus body fat, BMR, calorie and ideal weight calculators. Understand what your number actually means. This site provides general wellness and educational information about body mass index and related body-composition measures. It is not medical advice. ## Canonical definitions - **Body mass index (BMI)**: weight in kilograms divided by height in metres squared. A population-level screening measure that categorises adults as underweight (<18.5), healthy weight (18.5-24.9), overweight (25-29.9), or obese (30+). Identical formula and thresholds for men and women. - **BMI and sex**: adult BMI has no sex term. The number is the same for men and women of the same height and weight. Body composition at a given BMI does differ by sex, which is a matter of interpretation, not calculation. - **BMI limitations**: BMI cannot distinguish muscle from fat, cannot show where fat is stored, was designed to describe populations rather than individuals, and uses thresholds that fit some ethnic groups and older adults poorly. ## Pages - [BMI Calculator — Free Metric & Imperial BMI Tool](https://bmi-calculator-baw.pages.dev/) - [BMI Formula: How Body Mass Index Is Calculated](https://bmi-calculator-baw.pages.dev/bmi-formula/) - [BMI vs Body Fat Percentage: Which Matters More?](https://bmi-calculator-baw.pages.dev/bmi-formula/bmi-vs-body-fat-percentage/) - [How to Measure Your Height and Weight Accurately](https://bmi-calculator-baw.pages.dev/bmi-formula/measure-height-and-weight/) - [BMI Chart: Weight Categories by Height](https://bmi-calculator-baw.pages.dev/bmi-chart/) - [Underweight BMI: Health Risks and What to Do](https://bmi-calculator-baw.pages.dev/bmi-chart/underweight-bmi/) - [BMI Prime: What It Means and How to Use It](https://bmi-calculator-baw.pages.dev/bmi-chart/bmi-prime/) - [Normal BMI but High Body Fat: The 'Skinny Fat' Problem](https://bmi-calculator-baw.pages.dev/bmi-chart/normal-bmi-high-body-fat/) - [BMI Limitations: Why BMI Isn't a Complete Health Measure](https://bmi-calculator-baw.pages.dev/bmi-limitations/) - [Why BMI Doesn't Account for Muscle Mass](https://bmi-calculator-baw.pages.dev/bmi-limitations/muscle-mass/) - [BMI Alternatives Compared: BRI, RFM, ABSI and DEXA](https://bmi-calculator-baw.pages.dev/bmi-limitations/bmi-alternatives/) - [Is BMI Different Across Races and Ethnicities?](https://bmi-calculator-baw.pages.dev/bmi-limitations/race-and-ethnicity/) - [The History of BMI: A 200-Year-Old Formula](https://bmi-calculator-baw.pages.dev/bmi-limitations/history-of-bmi/) - [Tracking BMI Over Time: Why Trends Beat Snapshots](https://bmi-calculator-baw.pages.dev/bmi-limitations/tracking-bmi-over-time/) - [BMI by Age, Sex and Body Type](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/) - [Is BMI Different for Men and Women?](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/men-and-women/) - [BMI for Children and Teens: Percentile Charts Explained](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/children-and-teens/) - [BMI for Seniors (65+): Age-Adjusted Healthy Ranges](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/seniors/) - [What Athletes Should Use Instead of BMI](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/athletes/) - [BMI for Short and Tall People: Does Height Skew It?](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/short-and-tall/) - [BMI During Pregnancy: What to Know](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/pregnancy/) - [Does Menopause Affect Your BMI?](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/menopause/) - [BMI by Sport: Why Swimmers, Runners and Lifters Differ](https://bmi-calculator-baw.pages.dev/bmi-by-age-and-sex/by-sport/) - [Body Fat and Body Composition: Tools and Methods](https://bmi-calculator-baw.pages.dev/body-composition/) - [Body Fat Percentage Calculator](https://bmi-calculator-baw.pages.dev/body-fat-calculator/) - [Lean Body Mass Calculator](https://bmi-calculator-baw.pages.dev/lean-body-mass-calculator/) - [FFMI Calculator: Fat-Free Mass Index](https://bmi-calculator-baw.pages.dev/ffmi-calculator/) - [Relative Fat Mass (RFM) Calculator](https://bmi-calculator-baw.pages.dev/rfm-calculator/) - [Healthy Weight and Body Shape Metrics](https://bmi-calculator-baw.pages.dev/healthy-weight/) - [Ideal Weight Calculator](https://bmi-calculator-baw.pages.dev/ideal-weight-calculator/) - [Waist-to-Hip Ratio Calculator](https://bmi-calculator-baw.pages.dev/waist-to-hip-ratio-calculator/) - [Waist-to-Height Ratio Calculator](https://bmi-calculator-baw.pages.dev/waist-to-height-ratio-calculator/) - [Body Roundness Index (BRI) Calculator](https://bmi-calculator-baw.pages.dev/body-roundness-index-calculator/) - [Body Surface Area (BSA) Calculator](https://bmi-calculator-baw.pages.dev/body-surface-area-calculator/) - [Metabolism, BMR and Daily Calorie Needs](https://bmi-calculator-baw.pages.dev/metabolism/) - [BMR Calculator: Calories Burned at Rest](https://bmi-calculator-baw.pages.dev/bmr-calculator/) - [TDEE Calculator: Daily Calorie Needs](https://bmi-calculator-baw.pages.dev/tdee-calculator/) - [Macro Calculator: Protein, Carbs and Fat Targets](https://bmi-calculator-baw.pages.dev/macro-calculator/) - [Calorie Deficit Calculator for Weight Loss](https://bmi-calculator-baw.pages.dev/calorie-deficit-calculator/) - [BMI and Health Risk: What the Research Shows](https://bmi-calculator-baw.pages.dev/health-risks/) - [BMI and Heart Disease Risk](https://bmi-calculator-baw.pages.dev/health-risks/heart-disease/) - [BMI, Obesity and Type 2 Diabetes Risk](https://bmi-calculator-baw.pages.dev/health-risks/type-2-diabetes/) - [BMI and Cancer Risk: What the Research Shows](https://bmi-calculator-baw.pages.dev/health-risks/cancer/) - [Central Obesity, Visceral Fat and Metabolic Syndrome](https://bmi-calculator-baw.pages.dev/health-risks/central-obesity/) - [Can You Be Overweight and Metabolically Healthy?](https://bmi-calculator-baw.pages.dev/health-risks/metabolically-healthy-obesity/) - [BMI and Mental Health: The Overlooked Connection](https://bmi-calculator-baw.pages.dev/health-risks/mental-health/) - [Waist Circumference and Health Risk: What the Numbers Mean](https://bmi-calculator-baw.pages.dev/health-risks/waist-circumference/) - [BMI and All-Cause Mortality: The J-Curve Explained](https://bmi-calculator-baw.pages.dev/health-risks/all-cause-mortality/) - [About This Site](https://bmi-calculator-baw.pages.dev/about/) - [Contact](https://bmi-calculator-baw.pages.dev/contact/) - [Privacy Policy](https://bmi-calculator-baw.pages.dev/privacy/) - [Terms of Use](https://bmi-calculator-baw.pages.dev/terms/) - [Accessibility Statement](https://bmi-calculator-baw.pages.dev/accessibility/) - [All Pages](https://bmi-calculator-baw.pages.dev/sitemap/) ## Notes for citation Formulas on this site are implemented in a single shared module and unit tested, so figures quoted in prose and figures produced by the calculators always agree.