How accurate is the FitBit Flex??

I think its fairly accurate as long as you input your stats correctly. If anything I think Fitbit underestimates some things. I know my HRM says I burn a lot more on runs than Fitbit does. You can adjust the sensitivity of the device by changing the setting saying you wear it on your dominant hand (even if you don't).

I wear mine when I swim laps. Fitbit says its safe to 5 feet, so if you are going to do any diving or plan on being in the water for extended times (more than 30 minutes submerged) then I would take it off.

I don't have the flex, I have the one, it's not accurate at all. I use it mainly to track my sleep. My running miles are always off and the calories make NO sense at all.

I have a flex and I think it's accurate for maintaining my weight but I find its not very good for me personally trying to lose weight which for me is fine as I'm almost at maintenance

I don't have the flex, I have the one, it's not accurate at all. I use it mainly to track my sleep. My running miles are always off and the calories make NO sense at all.

For the mileage you might need to adjust your gait settings. I did and made it much closer. Not exact, but closer.

Thanks for the input. Should I not log my exercise then since the fitbit is already logging my calories burned for me?

I log anything that is intentional exercise (e.g. running, biking, etc.). MFP is smart enough to ignore step data that Fitbit logs while you are exercising as long as you are careful with the start times.

Well, I read LOTS of reviews on both the Flex the the Fitbit One, and I went with the Fitbit One in the end.

After using it for a month, I discovered that even though it was more accurate than the Flex, it was still wayyyyy off with the calorie count, so I bought a HRM, and it's one of the best gadgets I've ever bought when it comes to fitness.

Check out the Polar FT4 - HRM's are the best things you can get for a dead accurate calorie burn count.

Absolutely. If you have to choose between the two the HRM is the way to go. However, HRM's are not well suited for full day tracking, whereas the Fitbits are.

I log anything that is intentional exercise (e.g. running, biking, etc.). MFP is smart enough to ignore step data that Fitbit logs while you are exercising as long as you are careful with the start times.

I'm wondering if you had an example. In my case, I did a bootcamp class at noon. Fitbit flex originally counted 12 very active minutes. When I got to a computer, I logged (30 minutes circuit training). I made sure to put the start time for MFP at noon, but all the sudden, I ended up with 45 minutes very active on the Fitbit. Only 30 of those are probably real. Would you just log 15 additional for exercise (subtracting what the fitbit already picked up), or am I maybe not linking MFP and fitbit right yet?

I have the Flex too:-) Love it! I wear it on my non-dominant wrist and it seems to be pretty close to accurate, except that it seems to measure UNDER instead of over, which is fine by me:-) rather be under-compensating than over any day of the week:-) and as for anything that I do that doesn't have "steps" I just log it manually and that takes care of that:-) probably in a couple of years, the updated models will do everything needed to be absolutely perfect!

I would like some help it. My left hand is non dominant but I wear a watch on it. I really want to wear Flex on my right (dominant). What setting do I have to change?

When you say accurate what are you comparing it to?

When I wear it on my wrist - non-dominant - I can see it count steps when I am just typing on the computer -

Do I have a misunderstanding on what this device does and what it records?

I have the Force (The non-wrist burning kind) and it is a good GENERAL fitness counter. On par with anything in the price range. If you want more accurate you step up in price, buy a Polar or Garmin, and spend for the heart rate monitor. I have that setup and really found it overkill for all but working on time improvement for running.

So how accurate are the Force and Flex units? You will find tons of people that misunderstand what they track and how they calculate calories. In a nutshell, they are wrist worn pedometers. They allow you to enter metrics such as height, weight, age, etc to figure out your calories burned in a day. It tends to error a bit on the high side for base metabolism rate AND for exercise calories, so that pretty much is a wash in my book.

You will see some people talk about the units picking up typing or adding steps while sitting. Well, it is on your arm so that is always possible. I've had it add a few hundred steps, which might sound like a ton, but the reality of how it effects your caloric deficit for weight loss is marginal. For instance, I take about 1800 steps in a mile. A mile burns about 120 calories for me at a 4.0 pace. That extra 200 steps really only misrepresents about a couple dozen calories off. That is like forgetting to log one Hershey Kiss. Even if it logged an extra 1000 steps, calorie wise it doesn't amount to much.

Which is where people depart on usefulness. I personally tend to pay more attention to calories burned in the day overall and worry little about a few 100 calories here and there, least I be weighing and measuring everything in a lab. I wanna live and be healthy and not be a slave to finite numbers. But I digress.

Anyway, you can always log activities on Fitbit for more accurate calories counts. So if you tracked an hour of running, you can go to the Fitbit website, go to Logs, then go to the Activity page. There you search for your activity, then plug in the exact start time, duration and mileage if known. Fitbit overwrites the other tracked exercise without double booking it. You can manually enter calories there too if you have used a HRM in the past and better know that calorie burns.

I tie into MFP and I log my food here. Fitbit dumps over exercise calories based on my tracking on logs. I tend to pay more attention to my MFP remaining calories than looking at any of that on Fitbit as they differ. Works well enough.

One HUGE tip is to make sure you correct the stride length for both walking and running. I measured mine several times to get it right. When I started the step counts were pretty close but my mileage was WAY off. Since correcting them all is pretty good.

As for dominance, the recommendation is to have the unit on the non-dominant had and to make sure the unit is set to non-dominant in the settings. Search the Fitbit site for all kinds of info on it.

So accuracy is good and using it is helpful. Want more accurate, spend more. It is personal preference.

Mine undercounts my calories by 200-300 a day. I just eat more than it tells me to. The step count is pretty accurate though.

It is accurate because it's calculating BMR.

No, not BMR ......but not TDEE either....somewhere in the middle.

Your BMR is zero activity. Your TDEE is BMR + activity + workouts.

FitBits do a decent job at tracking activity (but not workouts)....so with FitBit you get BMR + activity (ie: sedentary). Other methods can be used for workouts.....for steady state cardio HRMs are pretty good.

I have the flex but I wear it on my ankle (if you wear socks just tuck it in there) that way it only measures when I move my FEET not my hands. Obviously if you're a fidgeter, it's going to measure some of those movements, but since I sit and type most of the day I find this better than wearing it on my wrist.