Various websites suggest that one step is approximately 3 feet in length for the average person.
So:
5,181 x 3 =15,543 feet
15,543/5,280 = 2.94375 miles
Not too shabby for an evening stroll. Bailey probably did an extra third since he was in full cat-chasing mode tonight.
I guess we needed to walk off all the frosted mini wheats we consumed for breakfast.