QTc Calculator

QTc is the QT interval of your heart rhythm adjusted for your heart rate. It helps clinicians determine if the heart's electrical recharging system is functioning properly regardless of how fast the heart is beating.

Bazett's is the most widely used. Fridericia's is often considered more accurate at heart rates above 100 or below 60 BPM because Bazett's tends to overcorrect at extreme rates.

A QTc over 500ms is considered high risk for Torsades de Pointes, a life-threatening ventricular arrhythmia. Normal thresholds are below 450ms for males and below 460ms for females.

Common causes include certain medications (antiarrhythmics, antibiotics, antipsychotics), electrolyte imbalances (low potassium, magnesium, or calcium), and congenital long QT syndrome.

Torsades de Pointes is a specific type of polymorphic ventricular tachycardia associated with QT prolongation. It can degenerate into ventricular fibrillation and cardiac arrest if untreated.

No. This tool provides QTc estimates for educational purposes only. ECG interpretation requires a trained clinician who considers the full clinical picture, including medications, electrolytes, and patient history.

You can. Look for the "Embed" button near the top of this calculator. It lets you pick a size, border style, and color palette, then gives you an iframe tag to paste into any webpage. The widget is responsive, loads fast, and costs nothing. More details at calculory.com/services/embed-calculators.