Find the battery compartment of the pedometer. On most models, the battery compartment is either on the backside of the digital display on the top cover or is a slit opening along the sides or bottom on the front of the pedometer.
Flick open the battery compartment cap or slit with your finger or any thin, flat-edged object. If the compartment has been sealed with screws, use a jeweler's screwdriver or any tiny screwdriver to remove the screws.
Remove the battery by either flipping the pedometer onto your hand or flicking it out by pushing a small, flat edge just underneath the battery.
Find a replacement battery that matches the one required by your model. Many designs use a CR2032 lithium battery, but the exact battery type is usually indicated near the battery compartment. Check the user's manual of your specific model for further verification.
Place the new battery into the compartment. Make sure it is inserted with the proper polarity.
Push the battery compartment cover back into its place. Use the tiny screwdriver to replace any screws that may have been removed earlier.
Re-enter any of your personal settings, such as weight or stride, since replacing the battery resets any previously entered data to its default settings.