Units
Pick how you'd like to enter and see your numbers — change this anytime.
Your height
Set once — used with every weight entry to work out BMI.
Log a weight
Add today's reading, or backfill an earlier date.
Trend
Background colour shows where each BMI value sits on the scale — hover a point for detail.
History
| Date | Weight | BMI | Category |
|---|
Frequently asked questions
Straight answers about BMI and how to track it well.
What is BMI (Body Mass Index)?
BMI is a quick screening number calculated from your height and weight. It doesn't measure body fat directly, but it's widely used as a starting point for talking about weight-related health risk.
What counts as a healthy BMI range?
For most adults, the World Health Organization defines 18.5–24.9 as the "normal weight" range, with the middle of that range generally considered the lowest-risk zone — that's the blue centre of the chart on this page.
How often should I track my BMI?
Weekly or monthly is plenty for spotting a real trend. BMI can shift day to day with water weight and food intake, so what matters is the direction of the line over weeks, not any single reading.
Is BMI accurate for everyone?
No. It doesn't distinguish muscle from fat, so it can overestimate risk in muscular or athletic people and underestimate it in older adults who've lost muscle mass. Use it as one data point, not a verdict.
Does BMI Compass store or share my data?
No. Every entry stays in your browser's local storage on your own device — there's no account, no server, and nothing is ever transmitted anywhere.