To vs Too: Here’s the Difference with Sentence Examples

To has two functions: it is (1) a preposition with many meanings, and (2) part of the infinitive form of verbs in English, e.g. to run, to walk, to say.

As a preposition, it usually implies direction towards:

I give this to you.

I moved to Sweden.

As part of infinitive verb forms, to has no meaning. It simply marks the infinitive. In most languages, the infinitive form is one word, so we treat English infinitives as if each were one word. This is why you might have been taught not to split the infinitive—not to put any words between to and the verb:

I want to study the Sumerian language.

To explain, it is a very ancient language.

To err is human.

In these sentences, the to has no meaning. You could understand the phrases equally well without it!

Too also has two different uses: (1) meaning also / in addition, and (2) meaning overly, as in too much, which means “more than is reasonable, appropriate, or expected.”

In meaning (a), too follows the phrase it modifies, which can be a noun, verb, or adjective:

She seems intelligent, and pretty too.

She wants to eat sushi and I do too.

We bought him drawing paper and pencils too.

In meaning (2), too precedes an adjective, adverb, or quantifier:

You are driving too fast; slow down!

You gave him too little; give him more.

The child is too young to see this movie.

As you can see too and to must be used in very specific ways.