Clinical Tools

ECG Axis Finder

Determine the QRS axis step-by-step using lead polarity. Each answer shades the hexaxial diagram to narrow down the axis.

NORMAL RIGHT EXTREME LEFT 0° ±180° -90° +90° +60° -60° +120° -120° -30° -150° +30° +150° I II III aVF aVL aVR

How It Works

  • Look at the QRS complex in each lead asked and determine if it is predominantly positive (upright), negative (downward), or isoelectric (equal up and down)
  • Each answer shades a semicircle on the hexaxial diagram — the overlap of shaded regions narrows the axis
  • The tool uses Leads I, II, and aVF to classify the axis as normal, left axis deviation, right axis deviation, or extreme axis

Axis Classification

  • Normal axis: -30° to +90°
  • Left axis deviation (LAD): -30° to -90°
  • Right axis deviation (RAD): +90° to +180°
  • Extreme axis (Northwest): -90° to -180°