Just Tool It /
BMI Calculator
On-device — nothing uploaded
BMI Calculator
Body Mass Index for adults. Educational only — not medical advice.
BMI categories
| Underweight | < 18.5 |
| Normal | 18.5 – 24.9 |
| Overweight | 25 – 29.9 |
| Obesity | ≥ 30 |
Why use BMI Calculator in your browser?
You may not want every number logged by a third-party calculator. BMI Calculator: Body Mass Index for adults. Educational only — not medical advice. Server-side tools upload or log inputs. Just Tool It does not: it uses local arithmetic in JavaScript; your numbers stay in the page. Close the tab and the working data is gone. That is zero-server processing and on-device security.
How to use BMI Calculator
- Open the tool on this page — no account or email required.
- Add your input by dropping a file, pasting text, or filling the form fields.
- Adjust options if available (quality, format, ranges, etc.).
- Run the tool and download (or copy) the result. Nothing was uploaded to Just Tool It.
Frequently asked questions
Is my data uploaded when I use BMI Calculator?
No. Just Tool It is a static web app. Your input is processed with local arithmetic in JavaScript; your
numbers stay in the page. You can verify in the browser Network panel: no file payloads are sent to our
origin for processing.
Is this tool free? Do I need an account?
Yes, it is free. There is no sign-up, paywall, or trial. We do not create user accounts because we never
receive your files.
Does it work offline?
After the page and any required libraries are cached (including via the service worker / PWA), many tools
keep working without a network. Large optional engines such as FFmpeg.wasm or OCR models still need a
one-time download.
How is this different from other free online tools?
Most free tools upload files to a cloud worker. Just Tool It emphasizes zero-server processing and
on-device security: files stay in browser memory until you download the output and close the tab.