QTc Calculator

QTc Calculator for Cardiology. Use QTc to screen for repolarization prolongation and medication-related arrhythmia risk, interpreted with ECG quality and clinical context.

How this calculator works

QTc formulas estimate heart-rate-corrected QT interval from measured QT and RR or heart rate.

Inputs used

  • Measured QT interval
  • Heart rate or RR interval
  • Correction formula

Clinical interpretation

Use QTc to screen for repolarization prolongation and medication-related arrhythmia risk, interpreted with ECG quality and clinical context.

Limitations and safety notes

Formula performance varies at heart-rate extremes and rhythm irregularity. Manual QT measurement and cardiology review may be needed.

References

  • Bazett HC. An analysis of the time-relations of electrocardiograms. Heart. 1920.
  • Fridericia LS. Die Systolendauer im Elektrokardiogramm. Acta Med Scand. 1920.

Editorial review and citation methodology

Reviewed by the Quick Medical Calculator Editorial Team. Last reviewed: June 19, 2026. The review checks calculator inputs, intended population, interpretation, limitations, and source alignment.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.