Yeah a fitness tracking device like a Fitbit, Jawbone, Garmin, etc are ideal although there are also many fairly cheap standalone pedometers you can buy from places like Takealot or Sportsmans Warehouse.
Many newer smartphones have a pedometer built in (like iOS has it in their Health app and Android has a standalone pedometer I think).
The latest Jawbone app for smartphones also lets you use the built-in pedometer stats with their more user-friendly and sophisticated fitness app.
Otherwise as a last resort: 6,000 steps is about 4.8 kilmeters or 60 minutes of brisk walking.



