ConverterHub

Heart Rate from RR Interval Calculator

Turn an RR interval into a heart rate in beats per minute.

Result

71 bpm
0.85 s

How it is calculated

The RR interval is the time between two successive heartbeats, and a minute holds 60,000 milliseconds, so HR (bpm) = 60000 ÷ RR (ms). The tool also shows the RR in seconds, RR ÷ 1000, to two decimals. The heart rate is rounded to a whole number of beats per minute. A single RR gives an instantaneous rate, the rate if every beat were spaced that far apart, not an average over a minute. The RR must lie between 240 and 3000 ms, which is roughly 250 down to 20 bpm; anything outside that range, or an empty box, shows no result. Educational use only.

Worked example

An ECG shows an RR interval of 850 ms between two beats. Heart rate = 60000 ÷ 850 = 70.59, shown as 71 bpm. In seconds, 850 ÷ 1000 = 0.85 s. As a check, an RR of exactly 1000 ms gives 60 bpm and 800 ms gives 75 bpm, so 850 ms falls between them, closer to 70 bpm.

Try this example →

Common mistakes

  • Entering the RR interval in seconds (0.85) instead of milliseconds (850). Values below 240 are rejected, so you get no result rather than a wrong rate.
  • Treating one beat-to-beat value as the person's resting heart rate. A single RR varies from beat to beat, so average many intervals before comparing with a resting rate.
  • Reading the whole-number bpm as exact. The result is rounded, so 70.59 shows as 71 and two nearby RR values can look identical.
  • Entering a heart rate and expecting the RR back. This tool goes only from RR to bpm; the reverse is 60000 divided by the bpm.
  • Using an RR measured across a missed or extra beat. Such a very long or very short gap gives a rate that does not reflect the underlying rhythm, and one beyond 3000 ms or under 240 ms is refused.

About this calculator

On an ECG or a chest-strap heart-rate monitor, the RR interval is the time in milliseconds between two consecutive R-wave peaks — the sharpest spike of each heartbeat's electrical signal. Because heart rate is simply how many of those beats occur per minute, the two are directly related by the formula HR = 60,000 ÷ RR interval (ms): a 1,000 ms RR interval corresponds to exactly 60 beats per minute, and an 800 ms interval to 75 bpm.

This conversion sits at the core of Holter monitors, fitness-tracker chest straps, and heart-rate variability (HRV) analysis, where researchers work with the raw RR series (sometimes called NN intervals when only normal beats are included) rather than a smoothed bpm figure, because RR intervals preserve the beat-to-beat timing detail needed to compute HRV metrics like RMSSD and SDNN.

Enter an RR interval in milliseconds and this calculator returns the equivalent instantaneous heart rate in beats per minute.

Was this helpful?

You can pick up to 3 reactions.

Comments (0)

  • Be the first to comment.

Popular calculators

Loan Calculator

Monthly payment, total interest and full amortization schedule.

Percentage Calculator

Percent change, percent of, and ratio calculations.

Discount Calculator

Calculate final price, savings, and discount amount.

BMI Calculator

Body mass index from height and weight (metric or imperial).

Age Calculator

Compute your exact age in years, months and days from a birth date.

Compound Interest Calculator

Calculate the final amount and interest earned with compounding.

All Calculators