Beginner, short distance (say 10-15 miles): average speed 12 mph. Most cyclists can achieve 10-12 mph average very quickly with limited training. More experienced, short-medium distance (say 20-30 miles): average 15-16 mph. Reasonable experience, medium (say 40 miles): average around 16-19 mph.
Stride length is measured from heel to heel and determines how far you walk with each step. On average, a man's walking stride length is 2.5 feet, or 30 inches, according to Arizona State University Extension. A woman's average stride length is 2.2 feet, or 26.4 inches, reports the school.
Your pedometer likely comes with an instruction manual which includes directions on how to measure your stride. Most pedometers suggest that you take 10 steps, measure the distance from start to finish, and divide by 10. The result is your stride length. Very fast. Very simple.