Is the pedometer on the iPhone accurate?

[MrHT]

I walk a lot to get exercise and my goal would be to walk 10 miles per day, three days per week. According to what I read, the average human being walks around 3 miles per hour, but I feel like I walk faster than that because I tend to walk fast because I'm always on the go. So assuming I walk 3 miles per hour, it should only take 3.5 hours to walk 10 miles, but sometimes I walk around that amount of time or longer and my iPhone is still showing me that I'm walking less than that.

For example, today I walked from 11am to 1pm. When I got home, my iPhone showed that I walked 5 miles. So around 3pm, I walked for another two more hours. When I got home at 5pm, my iPhone showed that my total miles walked for today was 9.2 miles.

I walked a total of 4 hours and am only showing 9.2 miles. That means I'm only walking 2.3 miles per hour. I can't be THAT slow.

I'm starting to question the accuracy of the iPhone and whether it might be worth getting an actual pedometer for more accurate results. But then again, maybe I am just a slow walker.

Is the pedometer on the iPhone accurate? Has anyone tried both an iPhone and an actual pedometer is test its accuracy?