Quick answer
Perdón
the everyday version
Disculpe
the alternative — see below for when
Which one to use
Use perdón when you bump into someone, interrupt, or need a quick small apology. It is short, neutral and works in every country.
Use disculpe when you approach a stranger to ask something. It is the formal usted form, so it sounds respectful with waiters, officials and people you do not know.
All the versions
Perdón.Sorry / excuse me — everyday, all purposes.
Disculpe.Excuse me — formal, approaching a stranger.
Disculpa.Excuse me — informal, to a friend or someone your age.
Con permiso.Excuse me — when passing through or leaving a table.
¿Me permite?May I? — very polite, squeezing past someone.
Where you are matters
In Mexico <b>con permiso</b> is extremely common when moving past people, while in Spain a simple <b>perdona</b> covers most of the same ground.
Check yourself
You want to ask a stranger for directions. What do you start with?