Calorie counter on Charge 4 not working

[SunsetRunner]

Expended calories appear to be irregular. For example, some days,  I seem to burn more calories per step and other days, very few calories. What is going on?

Moderator edit: updated subject for clarity. 

[SebWotan · Accepted solution]

Hello @SunsetRunner 

The calories is a function of your heart rate, so the calories per step could be very different whether you are slowly walking or going fast up a hill. 

[SunsetRunner]

HI Seb, 

I thought so too but the disparity still raises questions. For example,  some days  my fat burn zone minutes seem to result in more calories being burned and other days, it will be the opposite. I thought the active zone minutes reflect heart rates, meaning the higher the  zone, the more calories burned.

How does the counter work really?

[SebWotan]

That is a good question. Nobody knows really as the formula is kept secret. In principle yes the higher the zone the more calories you spend. 

A lot of fitness tracker overestimate Calories burned and Fitbit is no exception. To maintain my weight for example, I need to eat 20% less calories than what Fitbit tells me I burn, meaning for me it overestimates by 20%. 

[SunsetRunner]

Hi Seb, 

Thank you for sharing. Much appreciated.

Charge 4 is a frustrating kit. I have to uninstall and reinstall. it often to get it to sync. I never did that when I used Charge 2.

I don't have a great deal of confidence in 4.

[PinkisBest]

I have noticed the same issue over the past few months. For the same workout, same length of time and very similar heart rate there is a huge difference in calories burned. 
example:

day 1 body combat 60 mins, 147 avg bpm = 51 calories burnt

day 2 body combat 60mins, 154 avg bpm = 638 calories burnt

this is a huge variation and it is happening for all work outs. Swimming, weights, whatever it is, the stats are not comparable. 

yes I’ve logged out and logged back in.

yes I’ve restarted my fitbit and the app.

Don’t understand how to get more accurate data.

[SunsetRunner]

I share your frustration. Charge 4 is an irritating kit. I had no problems with Charge 2 and only got a replacement because of problems with the straps. Accuracy of data on Charge 4 is questionable. I wish we could get official explanation for the shortcomings.