In the majority of Istanbul’s bars and restaurants, service is not included. But tipping is not only expected for table services. So, for what services are tips expected, and how much?
In places where service is not included, it is custom to tip for the table services you received. And even in the handful of places where service is included (look for the words “servis dahil“), just as on mainland Europe the waiters will expect you to tip on top of that.
The rule of thumb is to leave a tip worth 10% of the bill in restaurants, cafés and bars. Bills are always brought to your table on a plate, in a box or in some kind of booklet. Although you can pay the bill with your credit card in 99% of the places, adding an amount to the original bill before paying with your credit card is not (yet) possible. Be prepared to have some cash money on you for tipping.
But restaurants, cafés and bars are not the only places where tips are expected. It is also custom to tip hotel staff, porters, hairdressers and musicians. Hamam attendants however expect 25% of the bill. Tipping taxi drivers is not custom, unless he helped you load the luggage.
When you travel to Turkey you should mind these rules.