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Is “Onto” One Word or Two?

In your everyday speech, you may give little thought to whether you’re using the word “onto” or the phrase “on to.” After all, they sound just the same when spoken. But what about when written? Does that tiny little space change the meaning between the word and the phrase? 

The word “onto” is correct as a preposition meaning “upon,” “to a position on,” or “into awareness of.” The two-word phrase “on to” usually involves the word “on” as part of a verb phrase, followed by the preposition “to.” So, it is correct to say, “Come up onto the porch” and “Carry on to wherever you’re going.”

Mastering “onto” and its close relative “on to” is problematic. But the information in this article will help you understand the difference between the two and how to use them correctly. You may even learn a few simple tricks along the way. 

What Does “Onto” Mean?

“Onto” is a preposition we most commonly use to describe an item’s transition from one place to a position on another surface. “Onto” implies movement and is synonymous with “upon” or “on top of” (source).

Consider its meaning in these sentences:

  • I stepped onto the escalator.
  • Spread the frosting onto the cake.
  • Let’s go onto the slide.

Remember that when we talk about being on top of something, we aren’t always speaking of physical objects. Instead, we might easily use “onto” to indicate that someone was on top of a problem or situation, like in these examples:

  • The power company says they’re onto resolving the outage.
  • I’m onto the issue with the neighbor’s barking dog.
  • She’s onto my request for her famous chocolate cake.

You may also use “onto” to describe someone who is aware of something. Saying a person is “onto” someone or something means they are conscious of the information another party might be trying to conceal.

  • I think he is onto the plans for his surprise party.
  • The teacher was onto the students’ plot to skip school.
  • You were onto me the minute you heard me whispering on the phone.

We occasionally use the word “onto” to indicate a transition from one location or activity to the next. This use of “onto” is less common, particularly in written English, because “on” is more acceptable. However, you can occasionally use it when speaking to emphasize where you placed an object on something.

  • I put his book onto the left side of the table.
  • Her water poured onto the floor.
  • Sam scattered the sand onto the sidewalk.

“On to,” expressed as a two-word phrase, has an entirely different meaning than the word “onto.” ; however, the word “on” is usually part of a verb phrase or phrasal verb. 

  • Students, please log on to your computers.
  • I hope to catch on to the concept quickly.
  • She held on to the idea of opening a restaurant.
  • It’s time to move on to our lesson on fractions.
  • After we finish this task, we’ll move on to the next one.
  • Lead us on to the next stop in the tour.

How Do You Use “Onto”?

You should use the word “onto” to indicate the transfer of something to a different surface. Saying something or someone is moving “onto” something else means the person or thing wasn’t there before. “Onto” implies movement, whereas “on” indicates a location.

Compare these two sentences:

  • The boy glided on the ice.
  • The boy glided onto the ice.

The second sentence clarifies that the boy was not on the ice before, and now he is. The first sentence is less specific. The boy may have just been entering the ice, or he could have continued to glide on it.

When you want to express that someone is fully aware of something hidden, you may say that they are “onto” the situation. Here are some examples of this use.

  • We’re onto the martians’ plan to take over the earth.
  • Mom is onto the fact that I’ve been staying up past bedtime.

You can also use “on to” to indicate that someone is transitioning to another location or activity. We typically reserve phrasal verbs like these for informal situations. You should opt for a verb that replaces the phrasal verb + preposition phrase entirely in formal writing because it is not precise.

  • It’s time to move on to the next round! 
  • Should we go on to the next episode?

Using “Onto” in a Full Sentence

“Onto” is a preposition that explains the relationship between other words in the sentence. Prepositions tell us an item’s location in relation to another object. They may also indicate when something happened or will happen.

To create a relationship, the preposition must have an object. For example, see how the prepositions (orange) in these sentences create a relationship between the subject (purple) and object (dark green) of the sentence.

  • The book is under the bed.
  • The letter “B” comes before “C.”
  • You should throw the ball at the target.

Because “onto” is a preposition, it, too, must always have an object.

  • [You] place the book onto the shelf.
  • I’m onto the problem.
  • [You] Step onto the platform.

Ending a Sentence with a Preposition

Now it’s time to address the elephant in the room. Is it okay to end a sentence with a preposition? You’ll be happy to know that this practice is no longer taboo. There are many cases where the grammatically correct sentence construction just sounds unnatural. 

The object is still there when the preposition is at the end of the sentence. They’re just out of order. Let’s look at some examples of awkward-sounding yet grammatically correct sentences and see how much better they sound if we bend the rules.

CorrectStill Correct, but Better
He’s looking to get onto a rental bike.He’s looking for a rental bike to get onto.
It’s not worth catching onto some secrets.There are some secrets not worth catching onto.
Onto which stair did you fall?Which stair did you fall onto?

In What Context Can You Use “Onto”?

Many people struggle with when to use the double pronoun “onto” instead of the simple preposition “on.” While there are some cases where you can use the two can interchangeably, their meanings are slightly nuanced.

Image by Borta via Pexels

If we break down the word “onto,” you’ll see it contains the simple prepositions “on” and “to.”

Saying something is “on” something is a matter of simply stating its location (source).

  • The dog is on the porch.
  • I put the hat on my head.

“To” is a directional preposition that indicates someone or something is going from one place to another. It suggests movement.

  • Let’s go to the movies.
  • Head to the left.

Therefore, you should always use “on to” instead of merely “on” when communicating that something was in one place and is now in another, except when “on” is actually part of a phrasal verb.

  • Phrasal Verb + Preposition: We moved on to the next station.
  • Preposition: The cat jumped onto the window sill.

When Can You Use “Onto”?

We’ve discussed using “onto” to indicate awareness or transition. But by far, we most often use this word to indicate movement to another surface. So you may still find it tricky to know when it’s the right word to use.

As the previous section explains, “on” usually refers to a stationary position. “Onto,” on the other hand, suggests movement from one location to another. Given that knowledge, you can generally trust that “on” is appropriate for describing fixed situations.

  • He is on the road. (He could be just standing there.)
  • She went on vacation. (She’s not here, but we don’t know what she’s doing.)

Similarly, you should use “onto” to describe something that moved.

  • I fell onto the bed. (I wasn’t on the bed, and now I am.)
  • Come out onto the beach. (I’m on the beach, and you’re not. Come join me.)

If you’re still struggling to make sense of these distinctions, there’s an easy trick you can try. Simply add the word “up” before the word “onto” in your sentence. Then, if it still makes sense, then “onto” is the right choice.

  • Correct: Let’s climb up onto the roof.
  • Incorrect: Let’s move up onto the next page.

When Not to Use “Onto”

The most common error we make when choosing between “onto” and “on to” is when “on” is part of the verb. Many phrasal verbs include the word “on.”

Here are some common phrasal verbs with “on.”

  • Carry on
  • Hold on
  • Go on
  • Get on
  • Catch on
  • Move on
  • Read on

You may often see the preposition “to” after these verb phrases. However, you should never combine them to form “onto” when “on” is part of the verb (source).

  • Correct: Hold on to me.
  • Incorrect: Hold onto me.
  • Correct: Go on to school.
  • Incorrect: Go onto school.
  • Correct: Carry on to your next class.
  • Incorrect: Carry onto your next class.

Try adding the word “up” in the above sentences, and you’ll see why they don’t work with the word “onto.” For example, you would never instruct someone to climb “up on top” of the school.

What Can You Use Instead of “Onto”?

The words “on,” “to,” and “onto” are all prepositions. So, unsurprisingly, you can often substitute one for another and still retain the intent of the sentence.

For example, you may use “on” instead of “onto” following action verbs, even though you may lose the connotation of the person or thing having been somewhere else previously.

  • Step onto on the top stair.
  • He walked onto on the stage.

You may often use “to” instead of “onto” to indicate transition or continuation.

  • Let’s move onto to our next example.
  • The baby graduated from formula onto to solid foods.

To avoid overuse of “onto,” try using any number of closely related prepositions or prepositional phrases.

We’re moving onto a solution.We’re moving toward a solution.
They went onto the terrace.They went out on the terrace.
He put the hat onto the snowman.He put the hat atop the snowman.
Come onto the boat.Come aboard the boat.
Spread the wax onto the car.Spread the wax all over the car.
She put the crown onto his head.She put the crown upon his head.

Open, Closed, and Hyphenated Compounds

As mentioned, “onto” is a preposition made up of the separate words “on” and “to.” When we combine two separate words to create a single word with a new meaning, we call it a compound word.

Compound words have their own distinct meaning from the two words that make them up. Moreover, compound words can be almost any part of speech: nouns, verbs, adjectives, adverbs, and prepositions. 

Because there is no space between the two words, “onto” is a closed compound word. Therefore, it should never contain a hyphen. Here are some similar words.

  • Bedroom
  • Weekend
  • Skateboard
  • Inside

Compound words that do contain a space are known as open compounds. Because they appear to be two separate words, open compounds are harder to identify. However, they still appear together as a pair and carry a different meaning when combined than when you use them separately. Here are a few common ones. 

  • Cell phone
  • Web page
  • High school
  • Hot dog

The third type of compound is the hyphenated compound. These are much harder to remember, so it’s always best to use a spell checker if you’re unsure whether a word or phrase should be hyphenated. Here are a few you’ll see often.

  • Long-distance
  • Over-the-counter
  • Mother-in-law
  • Runner-up

Preposition Types

As previously mentioned, prepositions are words that explain the relationship between two other things in the sentence. For example, they may indicate time, location, distance, spatial relationships, or other correlations. There are four main types of prepositions: simple, double, compound, and participle.

Image by Vlada Karpovich via Pexels

Simple prepositions are easy to recognize because they consist of one word. They typically come after a verb and before an object, creating a relationship between it and the subject. Here are some common simple prepositions and how we use them.

Single PrepositionExample
atThe dog is at the veterinarian’s office.
fromMilk comes from cows.
underThe cat is under the sofa.

Double prepositions are two prepositions we use together as closed or open compound words. We often use them to indicate direction.

Double PrepositionExample
across fromHe lives across from his aunt.
withoutDon’t leave home without a jacket.
intoStir the nuts into the batter.

Compound, or complex, prepositions are compound words made up of a simple preposition and one or more other parts of speech, often another preposition.

Compound PrepositionExample
on behalf ofI’m here on behalf of the governor. 
in addition toThis is in addition to the previous balance.
in front ofShe parked in front of the restaurant.

Participle prepositions are words that look like verbs but also function as prepositions. They end in “-ed,” “-en,” and “-ing.”

Participle PrepositionExample
duringHe naps during the afternoon.
includingEveryone is here, including me.
concerningThis meeting is concerning the merger.

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For more information on words that could be written as one word or two, you might enjoy reading Is “Everyday” One Word or Two? and Throughout or Through Out: Which is Correct?

Final Thoughts

The rules about when to use “onto” or “on to” are complicated. But the tricks you’ve learned should help considerably the next time you ask whether to use one or two words. So now, onto our next lesson!