Log height and weight over time and let BMI calculate itself, entry by entry — with a trend chart that shows change, not just today's snapshot. Saves in your browser. Free.
| Date | Height | Weight | BMI | Category |
|---|
💾 Saves in this browser only. BMI is a screening measure, not a diagnosis — it doesn't account for muscle mass, frame or age. Entering a date that already exists updates that entry.
Key takeaways:
A BMI history tracker logs height and weight at each check-in and works out BMI for you automatically, building a chart of change over weeks or months. It exists for a different question than our standalone BMI Calculator answers — not "what's my BMI right now" but "how has it moved since I started tracking."
Because BMI is a population-level screening number, the trend over time is generally more informative than any single reading, which is exactly what this tool is built to show.
BMI is a quick screening ratio of weight to height, useful at a population level but blind to individual body composition — it can't tell muscle from fat, and doesn't adjust for frame size, age or ethnicity. Tracked over time it's still a reasonable signal of overall trend, but it isn't a diagnosis and shouldn't be read as one entry at a time.
Pair this with the Weight Journal for the weight side alone, and the Body Measurement Tracker for tape measurements that show composition change BMI can't.
How is this different from the BMI Calculator?
The BMI Calculator gives you one number for right now. This tracker logs height and weight over time, calculates BMI for every entry automatically, and charts the trend — built for watching change over months, not a single result.
How is BMI calculated?
Weight in kilograms divided by height in metres squared: kg ÷ m². It's calculated automatically from what you log each entry.
Where is my BMI history stored?
Entirely in this browser's local storage, on this device. Nothing is uploaded. Export a CSV as a backup or to bring to a GP appointment.
What are the BMI categories?
The standard WHO adult ranges: under 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, 30 and over obese. BMI is a population-level screening measure and doesn't account for muscle mass, frame size, age or ethnicity.
Can I edit an entry?
Add an entry with the same date and it replaces the original — handy for correcting a typo.
Is BMI a diagnosis?
No. BMI is a screening tool, not a diagnosis of health status. For an assessment that accounts for your individual body composition and health, talk to a GP.