Why HeightFast exists

About Us

Height is one of those numbers everyone has in their own unit, and one nobody wants to convert by hand at the doctor’s office. HeightFast exists to make that conversion instant — and then to make the number mean something.

Our Mission

Feet and inches to centimeters is a two-line formula, but people reach for it dozens of times in a life: a passport form, a jeans size, a growth-chart check, a health screening. We put the calculation in front of you the moment you open the page, and layer on the two questions people actually care about — where does this rank, and how does it relate to my weight. No account, no fumbling.

Private by Design

HeightFast runs entirely in your browser. The heights, ages and weights you enter are processed by JavaScript on your device and never sent to a server. There is no account, no login, and nothing about you stored on our side.

How It Works

• Instant conversion. Everything is derived from the one exact constant of 1 inch = 2.54 cm, updated live in every unit.
• Growth percentile. With an age and sex, your height is compared to standard growth references and reported as a percentile rank in your group.
• Linked BMI. Add a weight and see your BMI and the healthy weight band for your height.
• Reference context. Averages and celebrity comparisons help you place the number in everyday terms.

What We Are Clear About

Heights, percentiles and BMI here are estimates and screening context, not medical diagnosis. Percentile uses population growth data; BMI does not distinguish muscle from fat. For anything health-related, a clinician — not a website — is the authority.

Questions or Ideas

Found a bug, want a population group added, or a question about the math? Reach us through the contact page.