Described herein are systems, devices, and methods for determining a users stride length and monitoring various aspects of the users activities. An apparatus worn or carried by the user may determine and track when a user takes a step and, based at least in part on user-specific information, determine an estimated stride length of the user associated with a respective step rate or step rate range. The apparatus may further monitor the physical location, speed, or pace of the user during an activity and, in conjunction with step count information, determine a verified stride length for the user associated with a respective step rate or step rate range. The estimated and verified stride length determinations may be stored and used to determine one or more aspects of a users subsequent activities, including but not limited to pace, speed, and calorie expenditure information, even when physical location information is unavailable.
