Clinical Tools

Advanced ECG Caliper

Upload an ECG, calibrate, and measure intervals with draggable calipers. Supports QTc (5 formulas), heart rate, mean intervals, and marching calipers.

Click to upload or drag & drop an ECG image
JPG, PNG — or Ctrl+V / Cmd+V to paste from clipboard

How to Use

  • Upload an ECG image (drag, paste, or click)
  • Calibrate first: click Calibrate, stretch the caliper across a known distance (e.g. 5 large boxes = 200 ms at 25 mm/s), enter the value, and click Apply
  • Add calipers: click Time or Amplitude, then click on the ECG to place. Drag the bars to adjust, drag the crossbar to move the whole caliper
  • Label calipers as RR, QT, PR, or QRS using the dropdown in the measurements panel. QTc auto-calculates when both RR and QT are labeled
  • March: select a caliper and click March to duplicate it to the right — useful for checking rhythm regularity
  • Mean interval: automatically calculated when 2+ time calipers are present
  • Zoom: slider, mouse wheel, or pinch. Drag empty area to pan