How would an app know what size your step was?
Smart phones also have GPS which track your movement.
Sensors on modern phones are quite accurate at estimating your steps based in already input stats like age, height, weight etc.
Smart phones also have GPS which track your movement.
What app do you suggest?
Or are the step counters not accurate?
Depends on the phone you have. S Health is really good if you have a Samsung phone, it does more than Google Fit. But Google Fit connects with other services like Fitbit/Strava and so on.
I use Google Fit for that reason.