Where accuracy usually holds up
During regular walking or running with the iPhone in a pocket, the motion sensors reliably detect the typical step pattern. For everyday comparison of your own activity across days and weeks, this level of accuracy is usually sufficient.
Where deviations can happen
Pushing a stroller or shopping cart can remove the arm motion the system partly relies on, which can lead to undercounting. On the other hand, if the iPhone sits loosely in a large bag or gets shaken heavily, for example on a bumpy ride, unrelated motion can occasionally be counted as steps.
Very slow walking or unusual movement patterns can also fall outside the recognized step pattern.
Not a medical measurement device
The iPhone step counter is meant for everyday personal orientation, not for medical diagnosis or scientific measurement. For health questions, qualified medical professionals are the right point of contact.
Tips
- Consistency over time matters more than an exact daily figure.
- Carry the iPhone the same way each day, such as in the same pocket, for comparable values.
- Expect a practical orientation, not scientific precision.