To, too and two are homophones, meaning the sound exactly the same as each other. That fact, coupled with the similar spelling, means we can often mix up to, two and too in writing. The three words have different meanings, so learning how to use them correctly is important. You will never encounter a situation in language when to, two or too can be used interchangeably.
To is one of the most common words in English, one which has a variety of functions. Indeed, the examples below are just a small selection of the uses of to, and not an exhaustive list.
Often, we use to as a preposition to express motion towards a physical destination or condition:
To can be used to as an identifier for someone affected by something:
To is used for identifying relationships:
To is used for indicating things that are attached:
To is also used as the infinitive marker:
And in place of an unspoken infinitive at the end of a sentence:
Too has two main functions: It’s used as an adverb to mean also or as well, or to mean excessively. Here is too meaning also or as well:
Too can also be used as an adverb that means excessively, or to a higher degree than is possible or necessary:
Because it’s a homophone of to and too, two can also get mixed up with these words. Two is a number, a group of more than one thing and less than three things.
Two can also specifically refer to years of age:
Because of the similarity in spelling of to and too, it might feel to some that the two words should be connected or closely related. They are not. Too will always mean also or excessively, whereas to is a preposition with the wide variety of functions listed above. Native speakers often mix them up to such an extent that it’s almost accepted at times, such as with the informal setting of social media. However, if you mix them up in formal situations, it can make your writing look clumsy, unprofessional and even lead to confusion. Consider the examples below:
This phrase indicates that Kevin is also going someplace (with other people).
This phrase indicates that Kevin will do something in the future.
Here are some more examples, showing the difference between to, too and two: