Knock twice or three times in knocking etiquette?

three times.

the most polite way to knock at the door is to knock three times, once in a while, and then knock a few times. Wait for an answer after knocking at the door. If you don't hear the right to say "come in", you should wait for 3 seconds and knock on the door again, and raise your voice moderately.

if the door says push or pull, it's very simple. just do as required. But in some places where there is no reminder, you must pay attention to it. At this time, sliding doors are more polite than pushing doors, because the two-way opening and closing doors are pulled in their own direction, so it is not easy to bump into others.

Precautions for knocking at the door

It should be noted that if you are visiting a relative or friend's house, you can call the other person's name while knocking at the door; If it is to a leader's home or a relatively public occasion, it is not recommended to make any noise.

If no one answers the door after knocking for several times, it should be that there is no one at home, so we should stop knocking to prevent it from affecting others. At this time, we should call the landlord. Sometimes we will encounter the wrong door. At this time, we should bow our heads and say sorry for finding the wrong person, and say sorry to show our respect.