In Amsterdam every official taxi must have blue number plates, a price list available from both inside and outside the taxi, and a taxi-driver's pass on the dashboard with photo and name.
Go to a taxi rank to get a taxi, because taxis are not allowed to stop everywhere. At a taxi rank you are not obliged to take the first taxi in line. Keep in mind that all licensed taxi drivers in Amsterdam must work with a defined fare structure.
Check this overview to see how the total the total price paid per journey is calculated.
Maximum start price: € 2.83
Maximum price per kilometre: € 2.08
Maximum price per minute: € 0.34