How are the calories calcullated by Fitbit?

[IsmeneP]

These days I use the Blaze. Somehow I think the calories burned are way over the top. (same with the surge and the charge HR which I also used).

For example today at 23:00 it shows me that today I burned 2700 calories. My average calories burned over the last month are, according to FItbit, about 2500.  I am a 'small person', 150 cm height and 57 kilos.

I count the calories I eat and they are always below 1800. If fitbit is correct in the calories burned I should be loosing weight, 1 kilos per 10 days (1 kilo = 7000 calories) but I am not.

Today I did a walk for 30 mins for a total of 2.3 km. Nothing strenuous I just walked the dog, and my HR did not go over 120. I did not even sweat! The blaze, using connected GPS, shows 170 calories burned from this exercise. Great.  But if I do 2.3 kms on a treadmill in 30 kins with a polar chest strap connected to the treadmill, the treadmill shows half the calories burned.

Why is there such a discrepancy between calories burned when using exercise machines (with a chest strap and the correct user data) and what fitbit is showing?

Could it be that Fitbit is over-calculating the calories burned?

Can a Fitbit moderator (or the development team) explain how the calories are calculated? From normal day to day 'living', as well as from exercise?

[CMeyer2001]

Hi @IsmeneP

Here is an article by Fitbit on how calories are calculated.  

http://help.fitbit.com/articles/en_US/Help_article/How-does-Fitbit-know-how-many-calories-I-ve-burne...

It is a combination of your basal metabolic rate (based on the information you've provided such as weight, height, etc), and the data from your activities.

I hope this helps!

[IsmeneP]

Article Text

How does Fitbit estimate how many calories I've burned?

Your basal metabolic rate (BMR) is the rate at which you burn calories at rest just to maintain vital body functions like breathing, heartbeat, and brain activity. Your BMR usually accounts for at least half of the calories you burn in a day and is estimated based on the physical data you entered when you set up your account: gender, age, height, and weight.

The calorie burn estimate that Fitbit provides takes into account your BMR, the activity recorded by your tracker, and any activities you log manually.

Your tracker's calorie count will reset each night at midnight and begin counting immediately thereafter. BMR is the reason your tracker starts the day with calories already burned—you've still burned calories even if you haven't gotten out of bed yet.

The article above in the following link:

http://help.fitbit.com/articles/en_US/Help_article/How-does-Fitbit-know-how-many-calories-I-ve-burne...

does not explain my question, does it?

The user data I entered are correct and I am saying that Fitbit is overcalculating calories, or is calculating un-realistic calories. Maybe by mistake, maybe, I would hate to day, as a marketing trick.

If what fitbit was correct, I should be loosing at least 1 or 2 kilos per month, and I am not!

Fitbit can I please get an official answer?

[SilviaFitbit]

I'll be happy to help you @IsmeneP! Thank you for the details that you've mentioned. As you could noticed with the help article that @CMeyer2001 sent you, calories burned are calculated based in your personal information. 

The amount of calories burned that you're seeing are going to be based in the exercise that you do daily. Let's say that today you went for a run, so you burned 500 calories and for the whole day you got 2600 meaning that daily your average is around 2100 but since you went for the run you got 500 extra calories. 

I would say that everyday is different just because there are some days that you exercise more than the others. I'd recommend to check your week's information by going to your Dashboard > log > activities > choose week > divide the total calories burned into 7 days and check if the data that you got is correct. 

Also, when you create a Fitbit profile, you'll have the option to set a Food Plan and by doing this, you'll be given a date of when you will reach that weight. This can totally help you more to know how much weight you're losing as well as how many calories you're eating and burning. 

Regarding your question about using another tracker besides Fitbit, each tracker tracks your information different. 

Hope this helps you clarify your questions.