Tipping in Sweden isn't as established as in many other countries. It's always welcome but not expected.
When eating out in Sweden it is common to to round up to the nearest big number. For example if your bill comes to 380 SEK, you can round up to 400 SEK. However, even if you choose not to leave a tip, it’s unlikely anyone will be offended. Often a service charge is included in the bill so check first. But giving a couple of kronor extra is a nice way of saying thanks for friendly service.
Tipping for special services provided by hotel staff is fine, but is not expected and is simply a matter of personal taste.
Taxi drivers can be given a few extra kronor.
Porters and cloakroom attendants often charge fixed fees. Doormen at hotels and restaurants are tipped modestly.