What this page does
A heart rate recovery calculator answers one question about a session that has already finished: after you stopped, how far did your heart rate fall. The number it works out is the difference between the peak you recorded during the effort and the reading you took a fixed time after you stopped — at 60 seconds, and again at 120 seconds if your watch kept that reading too.
The page is arithmetic and nothing else. There is no model behind it, no expected value and no cut-point. Your two or three readings go in, one subtraction comes out, and the same subtraction is printed three ways so it can be read as beats per minute, as a share of the peak you recorded, and as an average fall per second. When the 120-second reading is there, the page also prints how much of the whole fall happened after the first minute, which is the only thing two windows can show that one window cannot.
Everything runs in your browser. Nothing you type is sent to a server, there is no account and no upload. The other heart-rate pages on this site answer different questions: the fat burning heart rate page carries the age formula for an estimated maximum and the intensity band that sits under it, the heart rate zones by age page cuts an estimated maximum into five bands, and this page starts where both of those stop — at the readings you already have on the watch after the run.
How the drop is calculated
Three readings at most. Let P be the peak heart rate in the session, h60 the reading at 60 seconds and h120 the reading at 120 seconds, all in whole beats per minute. The two drops are:
HRR60 = P − h60 HRR120 = P − h120
The share of the peak is that drop divided by the peak, times 100, and the average fall per second is the drop divided by the 60 seconds it took:
s60 = 100 × HRR60 ÷ P r = HRR60 ÷ 60
The second-minute drop is not another subtraction from the peak. It is the difference between the two readings, which is the part of the fall that happened between 60 and 120 seconds:
d2 = h60 − h120 f1 = 100 × HRR60 ÷ HRR120
and f1 is the first minute's share of the whole two-minute fall. Note what is missing from all five lines: nothing here is fitted, nothing is extrapolated, and no reading is estimated from another. The page does not know what your heart rate was at 90 seconds and does not guess.
- P — the peak heart rate in the session, in whole bpm, 100 to 230. The highest number the watch recorded, not an estimated maximum.
- h60, h120 — the readings taken 60 and 120 seconds after you stopped, in whole bpm. Each has to sit below the one before it.
- HRR60, HRR120 — the drop at each window, in bpm.
- s60 — the 60-second drop as a percentage of P. It is a share of the peak you recorded, which is not the same thing as a share of your maximum.
- d2 — the fall between the 60-second and 120-second readings, in bpm.
A worked example: peak 182, 148 at 60 seconds, 131 at 120 seconds
The 60-second drop is 182 − 148 = 34 bpm. As a share of the peak that is 100 × 34 ÷ 182 = 18.7%, and as an average rate it is 34 ÷ 60 = 0.57 bpm per second. The 120-second drop is 182 − 131 = 51 bpm, which is 28.0% of the same peak. The second-minute drop is 148 − 131 = 17 bpm, and the first minute carried 100 × 34 ÷ 51 = 66.7% of the whole two-minute fall. Those are the six numbers the page prints for those three readings, and the page opens on them so the first thing you see is a worked answer rather than an empty form.
One arithmetic detail worth knowing before you compare two sessions: the same drop is a different share at a different peak. 34 bpm off a peak of 182 is 18.7%, while 34 bpm off a peak of 200 is 17.0%. That is not an error and it is not a judgement — it is what dividing by a different denominator does.
Taking the two readings yourself
The arithmetic is exact, so the only thing that can spoil the answer is the measurement. Five steps, in this order:
- Stop the watch the moment you stop moving. The stop button is the clock. If you walk for twenty seconds before pressing it, the 60-second reading is really a reading at 80 seconds and every number on this page shifts with it.
- Stay still for the full two minutes. Whatever you do in those two minutes, do the same thing next time. The page cannot correct for a difference between two readings that were taken differently, because it has no measurement of what you did in between.
- Read at 60 seconds, write it down, read again at 120. Two numbers, not a memory. The second one is what makes the second-minute drop possible.
- If the watch only stores a value every few seconds, take the nearest stored value and note which one you used. A reading taken from the nearest sample is a few seconds off; the same choice made twice keeps two sessions comparable.
- Take the peak from the same session. Not from last week, and not from your estimated maximum. The subtraction is only meaningful when all the numbers come from the same effort.
That is the whole procedure. It is a measurement routine, not a test protocol: this page does not tell you how hard to run, how long to run for, or what to do with the answer afterwards.
Pace, distance, and what this page will not relate the drop to
A fair question about a page like this is whether the drop depends on how far or how fast you ran. This page does not answer it, and the reason is in what the page is made of: nothing here is transcribed from a study, so there is no published figure on this page for how many bpm the drop moves per kilometre or per minute of pace. Printing one would mean inventing a coefficient, and a coefficient invented here would be indistinguishable from a measured one on the page.
What the page does instead is hold the window still. The reading is taken 60 seconds and 120 seconds after you stop, whatever the run was: a 5K and a marathon both get the same window, so a longer run does not get a longer look at the fall. The distance and the pace change when you stop, not how long the page watches for.
If you want to compare a 5K with a marathon on this page, the comparison is only like for like when the window is the same, the peak was taken the same way, and you did the same thing during the recovery. When those three hold, the difference between the two drops is a difference in the readings. When they do not, part of the difference is the method, and the page has no way to separate the two.
Supported range and limits
- Peak heart rate: 100 to 230 bpm, whole beats. Below 100 the subtraction stops describing a hard effort; above 230 the number is more likely a misread than a reading.
- 60-second reading: 30 bpm up to one below the peak. It has to be strictly below the peak, because a reading at or above it would make the drop zero or negative and the page does not print a negative drop.
- 120-second reading: optional. When present it must be 30 bpm or more and no higher than the 60-second reading, because a heart rate that climbs between the two windows is not a recovery and the page will not pretend it is one.
- Rounding: drops in whole bpm, shares to one decimal, the average rate to two decimals. One rounding, at the end, never halfway through a chain.
- Cost: none. No account, no email, no paywall, no daily limit, no request to a server.
- Privacy: every number is computed in your browser. Nothing you type is sent anywhere or stored — reload the page and it is gone.
- Works offline once the page has loaded, and on a phone.
What this page deliberately does not do
- No expected value and no cut-point. The page does not print a number your drop should beat, and it does not say whether yours is normal, high or low. A cut-point of that kind comes from studies that follow people over time and turn a reading into a verdict, and this page has no such study behind it and does not apply one.
- No age or sex reference table. No row of this page is broken out by age or by sex, and no table on it gives a reference value for a group. The peak is whatever you recorded.
- No medical advice. If you have a heart condition, or take medication that changes your heart rate, the numbers here are arithmetic on your own readings and not a target, a warning or a clearance. Ask the person who treats you.
- No maximum-heart-rate estimate. The page takes the peak you typed. Estimating a maximum from age is the fat burning heart rate page, and cutting that maximum into zones is the heart rate zones by age page.
- No heart-rate-reserve conversion. Every share here divides by the peak. Converting between a percentage of maximum and a percentage of reserve needs a resting reading and a different denominator, and this page does neither.
- No adjustment for pace, distance, weather, terrain or posture. The page has no measurement of any of them. It holds the window still and prints what the two readings say.
- No prediction. Nothing here forecasts a race time, a fitness level or a training response, and nothing here grades the number it prints.
Questions
What is heart rate recovery?
Heart rate recovery is the fall in heart rate after you stop. On this page it is one subtraction: the peak heart rate you recorded during the effort, minus the heart rate you read a fixed number of seconds after you stopped. At 60 seconds that is the peak minus the 60-second reading, and at 120 seconds it is the same subtraction with the later reading. Nothing else is measured and nothing is estimated.
How is the drop at 60 seconds calculated?
Two numbers and one subtraction. With a peak of 182 bpm and a reading of 148 bpm at 60 seconds, the drop is 182 minus 148 = 34 bpm. The page also divides that 34 by the peak, 34 divided by 182 = 18.7%, so the drop can be read as a share and not only in beats per minute, and divides it by the 60 seconds to get 0.57 bpm per second.
What drop should I expect after stopping?
This page prints no expected value, no normal range and no cut-point, so it cannot tell you whether your number is high or low. A cut-point of that kind would have to come from studies that follow people over time and turn a reading into a verdict about their health, and this site does not make health claims. What the page prints is your own readings, the drop, and the drop as a share of the peak you recorded.
Should I use 60 seconds or 120 seconds?
Both, if your watch keeps the numbers. The page prints the 60-second drop as the headline because it is the shorter window and needs only one extra reading, and it prints the 120-second drop and the second-minute drop beside it so you can see how much of the fall happened after the first minute. One window on its own cannot show that.
How do I take the two readings myself?
Stop the watch at the moment you stop moving, so the stop button starts the clock. Stay still for the full two minutes and do the same thing you did last time, because the page cannot correct for a difference between two readings taken differently. At 60 seconds read the number and write it down, then read it again at 120 seconds. If the watch only stores a value every few seconds, take the nearest stored value and note which one you used.
Why does the page ask for a peak heart rate instead of my maximum?
Because the peak is the number you actually recorded in that session, and the subtraction has to start from a reading rather than an estimate. Your maximum heart rate is a different quantity and this page does not estimate it; the fat burning heart rate page carries the age formula for that. If the effort was not all out, the peak sits below your maximum, and every share printed here is then a share of a number lower than your maximum.
Can I compare two runs with this page?
Only like for like. The page works on one session at a time, so a comparison means entering the second session and reading its numbers next to the first. The two are comparable when the window is the same 60 or 120 seconds, the peak was taken the same way, and you did the same thing during the recovery. The page does not correct for any of those differences, because it has no measurement of them.
Does the length of the run change the drop?
This page has no source that would let it answer that with a number, so it does not adjust the drop for distance or pace, and it prints no figure for how much the drop moves per kilometre. What it does instead is hold the window still: the readings are taken 60 and 120 seconds after you stop, so a longer run does not get a longer window. Comparing a 5K with a marathon means taking both readings the same way, or part of the difference is the method.