The electrocardiogram (ECG, EKG) is standardized for time and voltage.


Standard ECG paper has 1 mm squares in the X and Y direction, with thicker lines demarcating 5 squares.


The X axis of the strip indicates time in seconds or milliseconds.

The Y axis indicates voltage in millivolts.



1 mm square

5 mm square

X (time)

0.04 seconds (40 msec)

0.20 seconds (200 msec)

Y (voltage)

0.1 millivolts

0.5 millivolts


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