Alta step count inaccurate

[TraceyS2]

My Fitbit Alta is WAY out compared with the Apple Health app and Map My Walk. I mean literally WAY out. I know they measure things differently but this is ridiculous. Apple Health and MMW agree that I've done 1113 steps today, while Fitbit is telling me I've done 3586. I haven't walked much today and carry my phone with me pretty much all the time, even around the house. I can see that the iPhone apps could give slightly lower numbers if I walk 10 steps to the kitchen and forget to take the phone with, but that can't account for 2,500 difference. How do I determine which one is accurate? thanks

Moderator Edit: Clarified subject

[AlejandraFitbit]

Welcome to the Community, @TraceyS2.

For tips about improving accuracy, I recommend checking the help article: How accurate are Fitbit devices?.

Several things can affect the number of steps your Fitbit device records, including where you place the device, if you wear it on your dominant or non-dominant hand, and your stride length. If you're pushing a stroller or shopping cart, try putting your device in your pocket or use GPS to record your activity, if possible.

If it still seems like your device is undercounting or overcounting steps, try a step test. While you perform your step test, make sure you:

-Walk at a normal pace
-Don’t hold anything in your hands
-Put your arms down at your sides, swinging naturally
-Count 1 step for each foot
-To avoid getting an additional step when you bring your feet together, after you reach 100 steps:

1. Freeze in a split-stance. 
2. Move your hand up gently to check the step count on your device.  

Here’s the step test:

1. Restart your Fitbit device. For instructions, check the help article: How do I restart my Fitbit device?.
2. Put your device on your wrist.
3. Walk 100 steps, making sure to count a step each time one of your feet touches the ground.
4. Pause, then check your device to see your step count, and write down the number of steps you took and the number of steps your device counted. 
5. Perform the test 2 more times, walking 100 steps 3 different times. Each time, write down the number of steps you took and the number your device counted. 
6. Add the number of steps over or under that your device counted for all 3 tests. If your device counted 30 more or 30 fewer than the 300 steps you took, please let us know.

Let me know the outcome.