How do you know whether to use “onto,” or “on to” in your sentence? I find authors often confuse these two in work I edit, so here’s the tip I use to decide which one would be correct in any particular sentence.

Onto is a preposition that indicates either movement to a position on or in a state of awareness about.

On to is a combination of an adverb (“on”) and a preposition (“to”). The adverb “on” indicates position and the preposition “to” indicates movement.

You can see why these two may be frequently confused. Yet the following two sentences have very different end results:

  • I drove up Broadway and on to the bank to deposit my check.
  • I drove up Broadway and onto the bank to deposit my check.

In the first sentence, I’m just running an everyday errand, taking Broadway to get to my bank. In the second sentence, I’ve still driven up Broadway but I parked my car on top of the bank to deposit a check.

I actually picked up a trick from The Chicago Manual of Style on how to determine which of these two options to choose. If you can insert the word “up” before “on” and the sentence still makes sense, “onto” would be the correct choice to make.