QTc Calculator (Bazett & Fridericia)
Rate-corrected QT by the two standard formulas — the drug-safety number with thresholds shown.
Bazett (1920) remains the default but notoriously over-corrects at fast rates — cardiology and drug-safety studies increasingly prefer Fridericia, which is why both appear. The 500 ms line is where torsades risk climbs steeply and QT-prolonging drugs (the list is long: antiemetics, antipsychotics, macrolides, antifungals) get stopped. Manual measurement beats machine-read QT at extremes.
Formula
Reference aid for healthcare professionals only. Every result must be independently verified before clinical use. Never use this tool for self-medication or to replace clinical judgement.
Rate-corrected QT by the two standard formulas — the drug-safety number with thresholds shown. The QTc Calculator (Bazett & Fridericia) is a free, private qtc calculator tool — every result computes instantly in your browser with no sign-up and no data upload.
About QTc Calculator (Bazett & Fridericia)
Bazett (1920) remains the default but notoriously over-corrects at fast rates — cardiology and drug-safety studies increasingly prefer Fridericia, which is why both appear. It applies Bazett: QTc = QT ÷ √RR; Fridericia: QT ÷ ∛RR (RR in seconds). Use the QTc Calculator (Bazett & Fridericia) to get an instant, clearly-explained result with the working shown step by step — free, private and with the source method cited.
How to use QTc Calculator (Bazett & Fridericia)
- 1Enter your details in the QTc Calculator (Bazett & Fridericia) input fields above.
- 2The result updates instantly with the working and reference bands shown.
- 3Adjust any value to explore how it changes the outcome — it's free and unlimited.
Why use QTc Calculator (Bazett & Fridericia)?
- ✓Instant qtc calculator result that recomputes as you type — no waiting, no page reloads
- ✓100% client-side: your health data never leaves your browser
- ✓Shows the actual formula and your numbers substituted in, so you can see exactly how the result is reached
- ✓Based on published, citable sources (Bazett HC, Heart 1920; Fridericia LS, Acta Med Scand 1920)
- ✓Free forever with no sign-up, account or app install
Frequently asked questions
How does the QTc Calculator (Bazett & Fridericia) work?+
Bazett (1920) remains the default but notoriously over-corrects at fast rates — cardiology and drug-safety studies increasingly prefer Fridericia, which is why both appear. The calculation uses the formula: Bazett: QTc = QT ÷ √RR; Fridericia: QT ÷ ∛RR (RR in seconds). Everything runs instantly in your browser as you type — your inputs are never uploaded.
Is the QTc Calculator (Bazett & Fridericia) accurate, and what is it based on?+
The method is traceable to authoritative sources, including Bazett HC, Heart 1920; Fridericia LS, Acta Med Scand 1920; Drew BJ et al., Circulation 2010 — torsades prevention. Results are estimates — individual variation always applies, so treat the output as a well-grounded starting point.
Is the QTc Calculator (Bazett & Fridericia) free and private?+
Yes. It's completely free with no sign-up, and all computation happens locally in your browser, so none of your health data ever leaves your device.
Can I use this for medical decisions?+
This is a reference aid for healthcare professionals and must be independently verified. It is not for self-diagnosis or self-medication.
What can I use the QTc Calculator (Bazett & Fridericia) for?+
It's commonly used for qtc calculator, bazett formula, corrected qt. Rate-corrected QT by the two standard formulas — the drug-safety number with thresholds shown.
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