Our Mission
Most BMI calculators treat everyone the same, applying fixed adult categories regardless of age. But a child's healthy BMI looks completely different from an adult's — it depends on age and gender-specific growth patterns. HeightWeightCalculator.org gives parents and adults separate, appropriate tools, plus a body metrics log to see real progress over time.
Our Methodology
For adults, we use the standard BMI formula (weight in kg divided by height in metres squared) with WHO-standard categories. For children and teens, we use an approximate age- and gender-adjusted percentile model, and are transparent that a pediatrician's growth chart assessment is more precise for clinical decisions.
Important: we are an informational resource, not a medical provider. Read our full Disclaimer before making health decisions based on any calculator result.
Editorial Standards
We're upfront about what BMI can and can't tell you — including its well-known blind spots around muscle mass and fat distribution — rather than presenting a single number as a complete health verdict.
What We're Building Next
We're exploring waist-to-height ratio as an additional metric and export options for the Body Metrics Log, continuing the same standard: transparent math, no dark patterns, free forever.
Free, Always
No paywalls, no account required, no hidden premium tier.
Adult & Child Aware
Age-appropriate interpretation, not one-size-fits-all.
Privacy-First
Your inputs never leave your browser or touch our servers.