Accuracy of mobile pedometer

eliaslexred

How accurate would you say a pedometer application is?
I started using a pedometer on my phone a week ago and it's telling me that I average 17'000 steps a day (I only turn on the app when I am walking for exercise, so that figure doesn't include steps I take just going about my day).
On weekdays I go walking (3mph) for at least an hour and a half, but mostly it's two hours, and at the weekend for three hours. I'm pretty short (5"1) so I have to take more steps to go the same distance as someone else. My strides are between 50-60cm.

I'd love to be actually taking 17'000 steps a day but I don't know how accurate the app is. I have it on low sensitivity to avoid counting extra steps.