There are some slight differences in connotations of each letter ending. I'll order them in increasing formality.


Very personal. Used between lovers, family and close friends.


Very casual. Used between friends. Can be used between coworkers if you want to appear very casual, at the risk of sounding unprofessional.

Take care

Casual and used between friends.

Thanks or Thank You

'Thanks' is very casual and 'Thank You' is formal. Usually used in a business setting. 'Thank You' is a great way to end an email to a stranger, especially if you are making a request or asking a question.
 “Thanks”是非常随意的语气,而“Thank you”较为正式、常用在商业场合。给陌生人写邮件,尤其是你提出请求或者问问题的时候,“Thank you”是一个很好的邮件结尾。

Yours or Yours Truly or Truly

Casual or Business casual. A more personal, but still polite way to end the letter. You've probably met the recipient in real life.

Best or Best Wishes

Casual or Business casual. A polite way to end the letter. Can be used between friends or strangers.

Sincerely or Sincerely Yours or Yours Sincerely

Casual, Business casual or Formal. The standard letter ending. 'Sincerely' is the most versatile ending because it can be used to end either casual or formal correspondence. If you're unsure about how to sign your letter, use 'Sincerely'.

Regards or Best Regards

Business casual or formal. You would use this if the recipient is someone you haven't met in real life.

Formal. Used in business correspondence when the topic of the letter is serious. Sometimes used if there is a conflict between the sender and the recipient.

Using an ending that is too casual for the situation may not always be inappropriate. Conversely, using a casual ending can show your self-confidence. But to do this requires you to gauge whether the recipient would like a more casual conversation.