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Can Not and Cannot (The Difference)

The Quick Answer
Cannot (one word) is the most common expansion of the contraction can't.

Can't can also be expanded to can not (i.e., two words), but this is less common and usually reserved for emphasis. For example:

  • I cannot do it!
  • (Can't is usually expanded to cannot.)
  • I can not do it!
  • (This is considered more emphatic.)
Of course, the words can and not sometimes appear alongside each other when the not forms part of another construction (such as not only). For example:

  • Kevin can not only rap but dance too.
  • (Here, can not must be written as two words. It is not an expansion of can't.)

Cannot or Can Not?

Writers are often unsure whether to write cannot (one word) or can not (two words).


Cannot (one word) is the usual expansion of the contraction can't. It is possible to write can not as two words, but this is usually reserved for emphasis. For example:

  • A flower cannot blossom without sunshine, and man cannot live without love. (Max Muller)

  • Three things cannot be long hidden: the sun, the moon, and the truth. (Buddha)

  • I can not tolerate laziness!
  • (Here, can not is written as two words for emphasis. It allows the reader to emphasize the word not independently.)

Can Not (When Not an Expansion of Can't)

Although rare, it is possible for can and not (just like any two words) to be situated alongside each other. This is most common with the correlative conjunction not only... but also. For example:

  • I like that people who are not experts can not only understand but also become engaged by my work. (Leslie Fiedler)

  • A very quiet and tasteful way to be famous is to have a famous relative. Then you can not only be nothing, you can do nothing too. (P. J. O'Rourke)