QTc Interval Calculator

Calculate the corrected QT interval (QTc) to assess the risk of arrhythmias.

Input Metrics

Sex

QT Interval

Heart Rate

BPM

Disclaimer: This tool is for informational purposes only. ECG interpretation requires professional clinical training and must consider the full medical context.

ECG Analysis

Enter the QT interval and heart rate to calculate the corrected QT.

About this calculator

Overview

The QT interval represents the time from the start of ventricular depolarization to the end of ventricular repolarization. Because the QT interval varies with heart rate, it must be 'corrected' (QTc) to allow for clinical assessment and comparison.

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Pro Tips

Measure the QT interval from the beginning of the Q wave to the end of the T wave.
If you have a manual measurement of the RR interval in seconds, you can calculate the heart rate as 60 / RR.
The RR interval is the time between two consecutive R waves on the ECG.
Normal QTc limits are slightly higher for females than for males.

Fun Facts

"A prolonged QTc interval is associated with an increased risk of 'Torsades de Pointes', a life-threatening type of ventricular tachycardia."
"Bazett's formula is the most common but can over-correct at high heart rates and under-correct at low ones."
"Many medications can prolong the QT interval, which is why monitoring is often required for certain drug therapies."
"Congenital Long QT Syndrome (LQTS) is a genetic condition that affects the heart's electrical system."

Formula: Bazett's Formula: QTc = QT / √RR