How accurate is the charge 5 for calculating over all calorie burn

[Markcoughlan]

I am a 6ft 0 inch tall man , I am quite overweight at 280lbs. I have started to become very active lately in an effort to lose weight . I am currently doing 40 minutes weight training and 20k steps every day .  At the end of the day my fitbit says I have burned 5000 calories for the day. Before anyone says anything I understand BMR and I understand neat . I am just wondering if the device is overestimating how many calories I am actually burning do the scheduled exercise . I usually get the 40 mins weights and 20k steps in all in one go at the beginning of the day which takes about 3.5 hrs and then relax for the rest of the day . The burn according to the charge 5 for the direct exercise is 2500 cals and theres another 2500 over the course of the 24 hour day

1.Walk to the gym 40 mins 5000 steps 500 cals

2. Weights session 40 mins 500 calories 

3. Walk home from the gym 40 mins 5000 steps 500 cals

4. Walk in the local park 80 mins 1000 calories 

Does this sound right?

[SunsetRunner]

Hello @Markcoughlan 

Wow, first and foremost congratulations on your decision to start getting healthy and active! Woohoo 5,000 calories a day means your working hard and yes I believe it’s possible. So, yes I believe your Charge 5 is indeed accurate. I took the liberty of digging around the internet and found this great article you might find interesting here: https://www.livestrong.com/article/309810-how-to-burn-5-000-calories-per-day/ But to see how your Fitbit calculates your calorie burned you can read it here: https://help.fitbit.com/articles/en_US/Help_article/1141.htm  The most calories I burned once was 5,578 in a Fitbit beast mode challenge I did with friends that took dang near all day. 😂….my my general daily burn is 3,000 calories. So to answer your question is YES I think it’s right and welcome to BEAST MODE! 
😃 Keep at it, stay focused, stay hydrated and your gains will be rewarding. 

[lobo10]

walk in the park 80 mins
thats one long aess walk
good for you man

[LZeeW]

@Markcoughlan   My background is physiology with some biomedical engineering tossed in for good measure.

Fitbit uses the Mifflin-St Jeor equation to estimate BMR.  It is an improvement over older equations, as it is felt to be more accurate in obese people.  It uses your weight and doesn't use percent body fat.  Fat isn't metabolically very active, so it loses accuracy at higher weight and BMI.  I suspect any Fitbit will overestimate you BMR calories. 

Fitbit uses your heart rate to estimate activity calories.  So your activity calories are only as good as the heart rate monitor.  I recommend this YouTube video by The Quantified Scientist.  He reviews models of many brands of fitness trackers and is unbiased.  Fitbits can both over and underestimate your heart rate during exercise.  All wrist worn fitness trackers seem to be inaccurate during arm weight training.  You be the judge.

My answer is maybe, but unlikely.