QTc Calculator (Bazett)

About this calculator

This calculator finds the corrected QT interval (QTc) using Bazett's formula: QTc = QT / √RR, where RR is the interval between heartbeats in seconds. Correcting for heart rate matters because the raw QT interval naturally shortens as heart rate increases, so QTc lets you compare readings taken at different pulse rates on the same scale.

Clinicians, nurses, and cardiology or nursing students use it when reading an ECG to check for QT prolongation, a finding linked to certain medications and electrolyte imbalances. Enter the measured QT interval and either the heart rate or RR interval to get the corrected value.