Corrected QT (Hodges) Calculator

How it is calculated

The Hodges correction is linear in heart rate: QTc = QT + 1.75 × (HR − 60), with QT in milliseconds and HR in beats per minute. It adds 1.75 ms for every beat per minute above 60 and subtracts the same for every beat below 60, so at exactly 60 bpm QTc equals the measured QT. The tool shows both the corrected value and the correction itself, each rounded to whole ms. It never uses the RR interval, so you must enter heart rate, not RR. QT must be between 100 and 1000 ms and heart rate between 20 and 250 bpm; values outside those limits, such as QT typed in seconds, show no result. Educational use only.

Common mistakes

• Entering the RR interval in the heart-rate box. The field is beats per minute, so an RR of 800 ms must first be converted to 75 bpm (60,000 ÷ 800).
• Entering QT in seconds. It must be in milliseconds, so 0.36 s is 360; the value 0.36 is rejected and shows no result.
• Expecting the correction to be positive. Below 60 bpm it is negative, so the corrected QT is shorter than the measured one at slow rates.
• Comparing the result with a cut-off made for another formula. Hodges, Bazett, Fridericia and Framingham give different numbers at the same heart rate, so use the threshold of the method you chose.
• Using this as a clinical verdict. The tool only adds 1.75 ms per beat above 60; it knows nothing about the patient, the lead used or how the QT was measured.