Why your pedometer distance is wrong
Short answer: a pedometer estimates distance as steps times stride length. Many apps use a fixed stride, often 70 cm, for everyone. If you are taller or shorter than average, every kilometre is off. Enter your height so the app can estimate your own stride.
The formula
Distance = steps × stride length. 10,000 steps at 70 cm is 7 km; at 60 cm it is 6 km. A 10 cm difference in stride changes the result by a whole kilometre.
Estimate your stride from height
A widely used rule of thumb puts walking stride at about 0.41 times your height. At 160 cm that is about 66 cm; at 180 cm about 74 cm. For a closer number, walk 10 normal steps, measure the distance and divide by 10.
Other reasons distance drifts
Miscounted steps carry straight into distance: steps added in a car or missed while the phone sat on a desk. Fix the step count first, and the distance follows.
Doing it with Tallystep
Enter your height once and Tallystep uses your stride for distance and calories. If a day's steps are wrong, set them by hand; distance updates with it.
FAQ
How does a pedometer calculate distance?
Distance equals steps multiplied by stride length. Without GPS, the stride is an estimate.
What is a typical stride length?
A common estimate for walking is about 0.415 times your height for men and 0.413 for women — roughly 70 cm for someone 170 cm tall.
Is GPS more accurate for distance?
Outdoors, often yes, but it uses much more battery. A step sensor with your own stride is accurate enough for daily walking.