R-R Interval Calculator

How to calculate R-R Interval calculator?

The R-R interval is the time between consecutive R peaks on an ECG and can be derived from the heart rate or measured directly from the trace.

Key formula: R-R (ms) = 60000 / Heart Rate (bpm)

Using the R-R Interval calculator calculator: an example

Example values — use a heart rate of 70 bpm for a typical resting adult.

Step-by-step calculation:

1. Start with heart rate = 70 bpm.
2. Apply the formula: R-R (ms) = 60000 / 70.
3. Compute the value: ≈ 857 ms (rounded).
4. Optional: convert to seconds: 857 ms = 0.857 s.

Frequently Asked Questions

What is a normal R-R interval?

Normal R-R varies with heart rate; for a resting adult (60–100 bpm) R-R commonly falls roughly between 600 and 1000 ms.

How do I convert R-R from milliseconds to seconds?

Divide milliseconds by 1000. For example, 800 ms ÷ 1000 = 0.8 s.

Can R-R interval variability indicate arrhythmia?

Marked irregularity or abrupt changes in R-R intervals may suggest arrhythmia; always correlate with ECG morphology and clinical assessment.