Back to all calculators
♥
MK Created
📏

QTc Interval Calculator

Multiple validated formulas • Instant comparison

ms
200 ms
700 ms
bpm
30 bpm
200 bpm

Calculated QTc Values

All formulas shown for comparison

Clinical Interpretation

Note: QTc >500 ms significantly increases risk of torsades de pointes. Bazett formula is most widely used but tends to over-correct at high and low heart rates. Fridericia is often preferred for accuracy across a wide HR range.

Formulas Used

BAZETT
QTc = QT / √(RR in seconds)
FRIDERICIA
QTc = QT / (RR in seconds)1/3
HODGES
QTc = QT + 1.75 × (HR − 60)
FRAMINGHAM
QTc = QT + 154 × (1 − RR in seconds)
Reference: Standard electrophysiology formulas. Clinical decisions should integrate full patient context, medications, electrolytes (K⁺, Mg²⁺, Ca²⁺), and ECG morphology.
Disclaimer:
For educational and research purposes only.
All results must be verified by a qualified healthcare professional.
Use at your own risk.