I have written this several times over the years... but it is good information that bears repeating!
Click on above picture to enlarge!
Taxis in Sweden are not regulated. This means that it is free pricing and taxi companies can determine their own cost per minute/kilometer on their taxi meters. When the government deregulated the taxi industry, I am sure they did this with the best intentions (allowing smaller companies to be competitive). However, it has backfired. Small companies can legally charge double or even triple what larger companies do. As a Stockholmer, I know exactly which taxis to take or not. Unfortunately this means that the smaller companies end up preying on visitors who do not know better. This might sound a little bleak... but as long as you stick to rules above (checking the window sticker) you should be fine. Another rule of thumb is to stick with the larger companies, which all have similar pricing. Here at the Rival Hotel we use Taxi Stockholm among others. Other good companies include Taxi Kurir, Top Cab and Taxi 020. Another tip is to avoid hailing a taxi on the street and always have the hotel, restaurant or store call you a taxi. That way you are sure to get a "good" taxi.
And here you have some handy tips for catching a taxi at the airport!