Spring-Levered Pedometers: The most common type of less-expensive pedometers are spring-levered pedometers. A lever arm swings downward to close a contact to count a step. Then the spring returns it to its original position. You hear a click with each step, which can be annoying. A coiled spring retains its accuracy longer than a hairspring, and they are more expensive. If you are paying more than $15 for a pedometer, do the research to find out whether it is a coiled-spring pedometer so you are getting value for your money.
Favorite Coiled-Spring Pedometer: Yamax Digiwalker CW-701 Review - Compare Prices
Accelerometers - Piezo-electric Pedometers: These pedometers are more accurate than the spring-levered pedometers. They have no moving parts, so there is no clicking. An accelerometer uses a strain gauge, which measures how fast you are moving. This uses more battery power. So users need to replace the batteries more often -- every 6 months or so. These pedometers also tolerate being tilted to one side, giving more accurate readings for a wider array of body shapes. They can also be carried in a pocket. They will usually cost over $25.
Favorite Accelerometer Pedometer: Omron HJ-112 Review | Compare Prices
GPS Pedometers: GPS uses satellites to measure distance and speed. These do not give you a step count but give very accurate speed and distance measurements outdoors. They work poorly indoors and won't work for treadmill walking or walking in place. You can download an application to use the GPS built into your cell phone as a GPS pedometer, or buy a stand-alone GPS pedometer.
GPS Speedometer Reviews