Understanding step count variation with pace

[DJG66]

I don't understand my step count, although I know it varies with my pace.  I am a walker and I have noticed that the faster I walk the less accurate I feel like my step count is. Also, I interval walk so know my stride length varies with my pace. Here is my confusion, this morning I walked about 4.25 miles with an average pace of 14:28 and my fit bit recorded 5,538 step. I was quite surprised.  My iPhone step count was at 7,982. I went back out tonight and walked 1.69 miles with an average pace of about 19:00 and my fit bit recorded 2,885 steps. I'm trying to understand and figure out how to get the most accurate reporting.  Any advice? Thanks.

[AlvaroFitbit]

@DJG66 I hope you're doing well!

Let me help you with your step detection. Your device will detect the movement on your arm and translate that movement into steps. There are situations in which your arm may be still but you could be moving or walking. This may happen when you are pushing a cart or holding bars while walking or using a treadmill. For added sensitivity you can try wearing your device on your dominant hand but select that hand as non dominant on the device’s settings to make it more sensitive to movement. Also make sure your hands are moving so the device can properly track your steps.

Let me know how it goes.