Charge 4 calories not being accurate

[AJ44]

Hi everyone,

I have seen a couple of articles regarding the calorie count on the Charge 4, but with no real acknowledgement or solution of the apparent problem.

I am fit, 37 year old guy, 6ft 1 and 84kg - I was apparently burning between 420 and 450 calories in a 35 minute HIIT session (13 calories a minute). I was also burning 700 calories in an hours weights session (nearly 12 calories per minute). These numbers immediately questioned the accuracy.

I have since worn an Apple watch and Charge 4 simultaneously whilst doing an hour of weights - and the difference is significant - Apple Watch watch estimated a difference of 130 calories (even though average heart rate on both was within 1bpm).

Can anyone offer an explanation to this? I get wearing two devices at the same time will result in some differences, but surely not 130 calories?

Moderator Edit: Clarified subject

[AlejandraFitbit]

It's great to see you here, @AJ44.

Fitbit devices combine your basal metabolic rate (BMR)—the rate at which you burn calories at rest to maintain vital body functions (including breathing, blood circulation, and heartbeat)—and your activity data to estimate your calories burned. If your device tracks heart rate, your heart-rate data is also included, especially to estimate calories burned during exercise. The number you see on your Fitbit device is your total calories burned for the day. 

Your BMR is based on the physical data you entered in to your Fitbit account (height, weight, sex, and age) and accounts for at least half the calories you burn in a day. Because your body burns calories even if you’re asleep or not moving, you see calories burned on your device when you wake up and will notice this number increase throughout the day.

Note that in certain regions, you see kilojoules instead of calories. To change your units of measurement, see How do I change the units of measurement on my Fitbit device?.

Let me know if you need anything else. 🙂

[AJ44]

Hi @AlejandraFitbit 

Thank you for coming back to me.

I did consider the BMR impact - fortunately, Apple Watch provides two readings - one which is Total Calories (total including BMR) and one which is Active Calories (which isolates the calories burnt during the exercise, not including BMR).

Total Calories is the consistent reference against Fitbit reading, and this is the one which was 130 calories less. For comparison, the Active Calories came in 230 calories less. So I am afraid your explanation is not the reason, unfortunately.

I think, by anyones standards, burning close to 700 calories during an hour's weight session (so non aerobic exercise) is not possible. You have to be maintaining quite an intense activity to burn 12 calories a minute (even including BMR) - I certainly didn't maintain that for an hour by lifting weights.

Any other ideas? I think the device is clearly faulty

[WestHamDavid]

"Not being accurate"

You mean rubbish? 

Purchased a charge 4 to help me get an idea of my calorie burn, and it must be 2000 calories out for each day!  Done all the suggestions, and making sure it's located in the correct position on arm. The only way I can get near to near accurate is if I set my weight 4 stone (or 56lb lighter)

What's the point? 

Shall be returning this to Argos in the morning.

Thanks but no thanks

[AJ44]

@AlejandraFitbit Please can you come back to me?

[AJ44]

Ok, @AlejandraFitbit I guess you have no explanation and the Charge 4 is faulty and inaccurate. Thank you. I hope people read this before buying.

[Weishen17]

Dude... I'm almost roaming around the forum for answers and they'll just give you a generic answer, like... restarting your watch or how to wear the heart correctly but nothing works! Just move on to the polar or go with the Old Charge HR.

[AJ44]

Yeah man, just bought myself an Apple Watch. I guess you get what you pay for 

[eng3]

I first tried to estimate my actual BMR.  If you do almost the same activity (ie. sit on the couch all day) every day for a few weeks and strictly control what you wat (nutrition labels, weighing everything, etc) you can figure out your approx BMR.

Then, I adjusted my height in my profile until the BMR matched.  The estimates for the calories burned from exercise will be adjusted.

I've found it's alot closer now.

[AJ44]

Sounds like a lot of work man - don't really fancy sitting on the coach all day, every day for a few weeks to get the thing working. Good luck with that, I guess it's lock down at the moment

[AwilliamsLNK]

I just got the Charge 4 on Monday and so far, less than impressed.  Mine will not charge and I fought to get them to warranty it after doing all their trouble shooting. I too see quite a difference in my calories burned just based off my previous tracker. I did all my research and this tracker got great reviews. So far, not sure about this purchase. I will try the replacement they are sending but not holding my breath...

[Jxa77]

I've been diligently tracking my calories and comparing to my calorie output with 6 days a week exercise and was bitterly disappointed how utterly inaccurate (and basically garbage) the calories "out" feature is. Haven't lost an ounce because if the inaccuracy of it logging my exercise vs how many calories it allows me to eat. With such garbage data, what's the point of using this thing at all?? I'll be returning mine to the store. Waste of money.

[eng3]

Actually, in my case, if I blindly followed the calorie burn it indicated, and ate enough food to equal it, I'd probably gain at least 20lbs.  People have different BMR, especially if they've had alot of weight loss.  Fitbit has no way of measuring your BMR and uses a standard formula using your age, weight, and height.  In order to have the fitbit give me a useful number, I had to "calibrate" it to my BMR by lowering my height by about 1.5ft.  I've been using it for several months now and it seems to be fairly accurate now.

I mainly got the fitbit to have a good heart rate monitor.  I've tried many many other much cheaper ones and the fitbit has been the most accurate of the bunch.  Most other's I've tried are so bad that I could guess my heart rate more accurately.

[LostBoy]

just bought a charge 4 after doing a lot of research as I wanted an accurate wrist-worn HR monitor which I think it is, a lot better than my galaxy watch, and almost perfectly in line with my polar chest strap that I can't be bothered using all the time.

Also wanted the sleep tracking as I want to improve my sleep and a visual clue as to how bad it is might drive to improving this.  which it is.

But BMR way off, I'm 185cm/6'1 99kg/217lb and it's telling me I've burned 1700kcal by 3.30pm working from home at my desk.  Way off.  Maybe if my weight was pure muscle it might be accurate but it definitely isn't. 

[eng3]

Yes, HR is very accurate

Sleep isn't very good for me.  I have a desk job and spend most of the sitting. It will basically think I'm sleeping for several hours during the day as well as at night.  It never gets the start/stop time of my sleep correct.  You can go in and delete or edit it ofcourse, but it gets annoying doing it every day.

Try lowering your height until the BMR matches.  I don't know if it affects steps because I don't use that feature.   I wonder how many people are blindly following the fitbit calorie estimate and gaining tons of weight thinking they've burned so many extra calories.

[Kimblacklion]

It's hopeless. It pretty much doubles my actual calorie burn. Thank goodness I realised after the first week. Am using this to lose weight and get fit but now discount calorie burn, work it out online and keep calories under 1200. Hopeless.

And yes, unless my BMR is 200 calories an hour (it's not!) then the moderator explanation means nothing...

[eng3]

Yes, it's ironic that someone who blindly uses it out of box may end up gaining lots of weight.  I think there was even a study showing that.

Tweaking your height (or other factors) to change the fitbit's BMR estimate to a more accurate value is the only way I've been able to make it useful.

[Kimblacklion]

The BMR seems about right. It's the calculation that walking for 3.3 miles for an hour has somehow burned 606 calories that leaves me stumped 🙄

All other calculators say between 300 and 350 for my height and weight etc.

[Rich_Laue]

Of course without measuring the consumed O2 we are comparing two watches without have a set standard. As far as we know, neither may be correct. 

[Yanz]

I have the opposite problem - I'm pretty sure it UNDER estimates my calorie burn during exercise - I am only 5' in fairness but 45 minutes cycling at a pace of 30kmh and it estimated 100 calories burnt, bike estimated nearer 300.

That said I think my bmr calcs might be too high as despite being consistently in deficit in struggling to lose 😩