Sleep math doesn't add up

[SusanMT]

The math just didn't look right, so I started adding it up by hand a few times. In sleep cycles, where you can touch each phase, the white box pops up that says something like: REM 51 min, 3:42 - 4:36.  Well that's 54 minutes, not 51. I add up all the sleep stages and about half of them are off by some number of minutes. Also, the sleep stage total it gives isn't even an accurate total for the numbers it showed in each sleep cycle. Today the "Total" for Deep sleep was SIXTEEN minutes off of what the cycles showed I had!!!  In the end, I had a half hour more sleep than the FitBit total tells me I did. That's a significant math error when I'm trying to track how much sleep I get !

So TWO adding problems:  The Total given for each sleep cycle doesn't coincide with the range recorded for that cycle, and - The Grand Total for the different stages does not accurately add up the cycle totals given.

I know it isn't an exact science to begin with - sometimes I wake up and see the clock but lay there another 20 minutes awake. The FitBit often thinks I'm still asleep and records that awake time as sleep time. But It would be nice if the programmers could tweak this so it at least does proper math with what it does record.  Thanks!

[AlvaroFitbit]

@SusanMT Welcome to the Fitbit Community! I hope you're doing well! Sorry to hear that the data on your sleep records isn't accurate. Try updating your app on your phone. Also log out from your account, restart your phone and then log back in. Could you also provide some screenshots about this? 

I look forward to your reply!

[LindaGski]

Mine does the same thing.  Yet my Apple watch adds up correctly.  Last night my fitbit said I slept 4 hours and 41 minutes sleep. I actually got 7 hours and 5 minutes.  BIG difference!!!!

I am extremely disappointed in your product.

[amyblanes]

Hi. Here it is 2022, and I am still having the issue these folks above are having. Last night I went to bed at 10:49 and got up at 6:06. The app said I slept 6 hours and 34 minutes. This is clearly incorrect math so I went back and checked every other day is wrong. Do you know why that would be? 

[InsomniacYes]

@amyblanes is the app ALSO showing the correct times?  Mine has started cutting off the beginning of the sleep, indicating that I went to bed one or two hours later than I really did.  This is a semi-recent development.  I think it started in January but it might have been December. 

[Susibug7]

I've started noticing the same thing. I'm thinking of manually starting all my sleep times

[dxf]

It is now August 2022, I am experiencing the same issue with Fitbit Sense. Time spent in each sleep stage (REM, Light and Deep) added up does not equal to the total Time Asleep shown the app. Looks like the same issue has existed for years and across multiple Fitbit models. Is there an update? Thanks

[LindaGski]

Sadly, not that I'm aware of. 😞

[Krazimaz]

I have the same issue.  My total minutes of sleep never adds up to my total minutes of REM, light sleep and deep sleep.  Can be off 40 minutes or more.  Last night I was in bed for 6:09.  My awake time was 12 minutes, REM 50 minutes, 4 hours light sleep and 56 minutes deep sleep.  That adds up to 5 hours and 58 minutes, a difference of 11 minutes.  That time is correct as I know what time I went to bed and what time I got up,  everything else is wrong.   But on the initial summary it shows asleep 5:09 and awake 40 minutes.  This is 49 minutes less than adding up all the sleep cycles and 28 minutes more awake time than what is shown on the tables.  I can understand small differences but these are large differences.

[dxf]

Did anyone receive an explanation from Fitbit as to why this happens, and/or a possible fix at some point? When I contacted Fitbit support, they confirmed the issue but offered no explanation or a timeline for when it'd be fixed. 

[GreenDestiny]

I think its because fitbit does not count your awake times when adding up your total sleep time. Like if you are 6 hours in bed but you total awake time throughout the night is 1 hour it will just record 5hours.

Also from what I have observed, fitbit does not log less than an hour naps. And a minimum sleep of 3 hours for it to give the sleep phases.

My sleeo can be fragmented with awake times in between but so far its accurate for me and also the sleep score do reflect how I feel after waking up. Like if I just had 5 hours of sleep but my sleep score is somehow high. I should have felt lacking but indeed I feel well rested. The opposite is if I had 8 hours total in bed but I kept on waking up throughout the night so my sleep score is lower and indeed I dont feel rested for such nights.

So far mine adds up, been using a Charge 4 with updated version.