BMI Calculator
Enter height and weight to calculate BMI and see the category. Educational only (not medical advice).
How we calculate this
BMI is calculated from your height and weight. For metric units, we use: BMI = kg / m² (height is converted from centimeters to meters). For imperial units, we use the standard conversion: BMI = (lb / in²) × 703.
BMI categories shown are standard public-health screening cutoffs for adults: Underweight (< 18.5), Normal (18.5–24.9), Overweight (25.0–29.9), and Obese (≥ 30.0).
Sources
- World Health Organization (WHO) BMI classification (general reference): who.int
- NIH / PubMed research references (examples below) are provided for educational reading only.
Limitations
- BMI does not measure body fat directly or account for muscle mass.
- BMI may be less informative for athletes, older adults, or during pregnancy.
- BMI does not account for fat distribution (e.g., waist circumference).
- This tool is educational only and is not a diagnosis.
Related research (Zynava library)
BMI is a screening metric. If you’d like to explore research around weight and body composition topics, here are a few study links from Zynava’s research library. These links are for educational reading only.
- Effect of Vitamin D Supplementation on Lipid Profile in Overweight or Obese Women: A Meta-analysis and Systematic Review of Randomized Controlled Trials (PubMed, 2025)
- Vitamin D supplementation does not alter inflammatory markers in overweight and obese individuals: A systematic review and meta-analysis of randomized controlled trials (PubMed, 2024)
- Daily and Weekly High Doses of Cholecalciferol for the Prevention and Treatment of Vitamin D Deficiency for Obese or Multi-Morbidity and Multi-Treatment Patients Requiring Multi-Drugs-A Narrative Review (PubMed, 2024)
- Effects of vitamin D supplementation in obese and overweight children and adolescents: A systematic review and meta-analysis (PubMed, 2023)
- Vitamin D supplementation and energy and metabolic homoeostasis in obese and overweight subjects: a protocol for a systematic review (BMJ, 2021)
- Vitamin D supplementation in obese Sri Lankan children: a randomized controlled trial (PubMed, 2020)
- The effect of active vitamin D supplementation on body weight and composition: A meta-analysis of individual participant data (PubMed, 2024)
- Oral vitamin D supplementation and body weight in children and adolescents: a systematic review and meta-analysis of randomized controlled trials (PubMed, 2023)
FAQs
What is BMI?
BMI (Body Mass Index) is a screening measure based on height and weight. It’s used in population research and clinical screening, but it does not measure body fat directly.
Is BMI accurate for everyone?
Not always. BMI does not account for muscle mass, bone density, age, sex, or body fat distribution. Athletes and some older adults may be misclassified by BMI.
What BMI is considered “normal”?
For most adults, “normal weight” is typically defined as BMI 18.5–24.9. These are category cutoffs used in public health references.
Can BMI tell me if I’m healthy?
No. BMI is not diagnostic. Health depends on many factors—blood pressure, labs, diet, activity, sleep, mental health, and more. Use BMI as one data point, not a conclusion.
Should I try to change my BMI?
If you’re concerned, talk with a qualified clinician. Safe changes usually focus on sustainable habits (nutrition, activity, sleep) rather than chasing a single number.
Does Zynava recommend supplements for weight loss?
No. Zynava provides educational tools and research links. We do not provide medical advice or individualized supplement recommendations.