If you need qtc fridericia, qtc framingham and rr interval and you already have heart rate and qt interval, this calculator does the substitution for you. It suits a quick check, a homework answer you want to confirm, or any figure you need to sanity test.
What Is the QTc Calculator?
The qtc calculator gives you an estimate of qtc fridericia, qtc framingham and rr interval based on heart rate and qt interval.
It is a quick reference figure rather than a diagnosis, and it is most useful for tracking how a number moves over time rather than for interpreting a single reading.
How the QTc Estimate Is Worked Out
The calculation follows published reference relationships, so it is a reasonable approximation when the inputs are accurate. It assumes an average adult and does not account for individual variation.
If you are comparing two people, or the same person over a period of weeks, keep the method and the inputs identical. A change in the method can easily look like a change in the person.
What This Calculator Does Not Do
It does not diagnose anything, and it does not replace advice from a clinician. If a figure comes out at an extreme, or if it differs sharply from what you expect, that is a reason to speak to a professional rather than to adjust the inputs.
Nothing you type here is stored or sent anywhere. The whole calculation happens in your browser.
A Worked Example
Working through an example, with heart rate set to 10, qt interval set to 5, the calculator returns rr interval of 6, and qtc bazett of 2.04, and qtc fridericia of 2.75. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out qtc fridericia?
Enter heart rate and qt interval. The calculator then works through the relationship and reports qtc fridericia, qtc framingham and rr interval.
What does the qtc actually calculate?
It takes heart rate and qt interval and converts them into qtc fridericia, qtc framingham and rr interval using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter heart rate?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Does anything you type get stored?
No. The whole calculation runs inside your browser, and nothing you enter is uploaded, logged or sent anywhere.
Can I use this for a quick estimate as well as a precise answer?
Yes. The calculator is built for quick checks, so round your inputs to a sensible number of significant figures and the result will be just as useful. If you need more precision, keep the same method and add digits to the inputs rather than adjusting the method itself.