QTc Calculator
Correct the QT interval for heart rate using Bazett, Fridericia, Framingham, or Hodges. Flags sex-specific prolongation thresholds.
Raw QT interval from the ECG, in milliseconds. Typical adult range is 350 to 440 ms.
Used only to set the prolongation threshold (450 ms for males, 460 ms for females).
RR (ms) is computed as 60000 / bpm.
Bazett is the default because it is the most widely reported, but Fridericia and Framingham are more reliable outside 60 to 100 bpm.
Corrected QT (Bazett)
400 ms
Normal QTc range
QTc is in the normal range. Routine monitoring still applies if the patient is taking QT-prolonging medications or has structural heart disease. Bazett tends to overcorrect at fast heart rates, so cross-check the Fridericia value as well.
- Heart rate
- 60 bpm
- RR interval
- 1,000 ms
Comparison across formulas
- Bazett
- 400 ms
- Fridericia
- 400 ms
- Framingham
- 400 ms
- Hodges
- 400 ms
Medical disclaimer
This calculator is for educational use only. It is not a diagnosis and not a substitute for clinical judgment. QT measurement is operator dependent, electrolyte abnormalities and QT-prolonging medications can shift QTc substantially, and no single formula is universally accurate across all heart rates. If a real patient has a prolonged QTc, symptoms of arrhythmia, or is starting a QT-prolonging drug, consult a clinician or cardiologist before acting on this estimate.