About

ECG Digital Caliper is a free, browser-based tool for measuring intervals, durations, amplitudes, and areas on scanned 12-lead ECG paper recordings. Calibrate once (horizontal time + vertical voltage), then drag, click, or auto-analyze to extract clinically relevant measurements.

Privacy

Uploaded ECG images are processed in a temporary session on the server and are not retained after the session ends. Nothing is shared with third parties. For maximum privacy, run the app locally — full source is open and self-hostable.

Features

Manual calipers for HR / RR, P, PR, QRS, QT, Tp-e, P / V5 / V1 amplitudes
Polygon area tools for P, QRS, T waves
R-peak marking + automatic P / QRS / T boundary detection
Auto-analyze: digitization of the ECG trace and full wave segmentation
Image rotation (sub-degree precision) with anti-aliased super-sampled rendering
Zoom up to 10×, mobile + desktop installable as PWA
CSV export of all measurements

Medical Disclaimer

This tool is NOT medically validated. It is provided strictly for research, educational, and personal-study purposes. It is not a medical device, has not been evaluated by any regulatory body (FDA, CE, MHRA, TITCK, etc.), and must not be used to diagnose, treat, or make clinical decisions about any patient. Always confirm any finding using calibrated clinical equipment and the judgement of a qualified physician.

Author

Built by Dr Yusuf Hoşoğlu (2026). Feedback and bug reports welcome.

Contact

[email protected]

Tech

Python (Flask), OpenCV, NumPy, SciPy, vanilla JavaScript canvas, Bootstrap 5. Service worker enables offline-capable PWA install on Android, iOS, Windows, macOS, Linux.

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