Ensure vs Insure: How to Make Sure You Get It Right

Few languages have as many homophones — words that sound the same but are spelled differently and have different meanings — as the English language. Ensure and insure is one pairing which is commonly confused, with assure sometimes also being thrown into the mix.

Ensure, insure, and assure are all verbs related to the idea of “making sure.” Broadly, ensure means to make sure of (or guarantee) an outcome, while insure means to take out an insurance policy for something of value, and assure to remove doubt or say something with confidence.

In this post, we’ll take a closer look at these three verbs, giving examples to clarify their usage, as well as some simple tricks to tell them apart. But first, let’s look at why these words are so similar.

Historically just a spelling difference 

Distinguishing between ensure and insure can be tricky because for years it was simply a matter of spelling and regionality, much like centre and center. Both terms — as well as the constant third wheel assure — relate to the idea of “making sure” or “being sure” of something, and it wasn’t until the mid 19th century that people started distinguishing between ensure and insure.

Since they’re all related to the same idea and used in similar situations, it’s no wonder that people conflate them. In fact, some people and style guides still argue that you can use ensure and insure interchangeably (like the New York Times stylebook). These days, however, the general consensus in both British and American English is that they have distinct usages, so knowing how to tell them apart will help level up your writing and keep the grammar police off your back. 

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Let’s look at these words one by one to break it down.

Use ensure to guarantee an outcome

Ensure is considered a more widely applicable verb than insure since it’s more generally used to guarantee or make sure that something happens. Compared to insure, which is also a form of guarantee, ensuring something implies no contractual obligation nor particular precautions. Rather, it’s often used to describe one thing causing or leading to another, or someone (actively) making certain that something will or won’t happen — to make sure of an outcome or result.

Here are a few example sentences to make it a bit more clear:

Studying hard usually ensures good results.

She went to deliver the documents in person to ensure they wouldn’t get lost.

A sample sentence can be a great way to ensure your readers understand your message.

Notice how, in all of these examples, ensure is an active verb which makes something happen to someone or something else.

Examples of ensure from literature

As a relatively active verb, the word ensure is often used to show cause and effect — one thing or event ensuring a particular result or outcome — or to indicate implicit promises or relationships between people or things. 

Here are a few examples from literature:

““Good intention” is a hall pass through history, a sleeping pill that ensures the Dream.” 

— Ta-Nehisi Coates, Between the World and Me

“It's clear to me now that I have been moving toward you and you toward me for a long time. Though neither of us was aware of the other before we met, there was a kind of mindless certainty bumming blithely along beneath our ignorance that ensured we would come together. Like two solitary birds flying the great prairies by celestial reckoning, all of these years and lifetimes we have been moving toward one another.”

― Robert James Waller, The Bridges of Madison County

“Time ensures children never know their parents young.”

― Delia Owens, Where the Crawdads Sing

“The trick to happiness wasn’t in freezing every momentary pleasure and clinging to each one, but in ensuring one’s life would produce many future moments to anticipate.”

― Brandon Sanderson, Oathbringer

In these examples, ensure is used to soften the sentences and make them less direct, while still expressing cause and effect. This feels more poetic than saying, for example, “Children never know their parents young because of the passage of time.” It also allows the author to make things such as  “time” or “mindless certainty” — abstract nouns — into the subject of the sentence, with a sort of agency of their own. 

Use insure to cover something with an insurance policy

Insure used to simply be an alternative spelling for ensure, but has gained its own nuance of “making certain, especially by taking necessary measures and precautions,” according to Merriam Webster. More commonly, it means to take out a literal insurance policy for things like travel, health, house, or life.

Over the years, insure has thus evolved to specifically refer to a binding contract, insuring property or things of monetary value to receive compensation if that thing fails, breaks, or ceases to exist. If you use this interpretation, you’re less likely to get caught by the grammar police, so we recommend you separate ensure and insure according to this distinction.

Here are some example sentences with insure in action:

My brother bought an expensive sports car but forgot to insure it. It cost him a fortune to get it fixed when someone scratched it.

We recommend that you insure your flight ticket to get money back in case of cancellation, sickness, or other unforeseen circumstances.

Jennifer Lopez has insured her backside and other body parts for 28 million dollars to protect them against damage and risks.

In one sense, you can think of insure as a more passive verb than ensure, since it’s a last ditch effort if all else fails: a precaution or necessary measure meant to kick in only if something undesirable happens, but not necessarily the cause of an event. Of course, the act of insuring is an active decision which causes compensation, but thinking of it this way can help you keep the two apart.

Examples of insure from literature

If we’re being technical about it (which, in all fairness, this article is all about), you won’t find many examples of insure being used in literature. The reason is simple: few authors and readers find the topic of insurance a scintillating read, especially in fiction — and when they do, they commonly revert to the noun form “insurance” instead.

For fun, here’s an examples where insure was used when it probably should have been ensure: 

“Of all the means to insure happiness throughout the whole life, by far the most important is the acquisition of friends.”

― Epicurus, A Guide To Happiness

Either the old Greek philosopher Epicurus was looking to sign an insurance policy for happiness, or he meant to say that making friends is the best way to ensure — or guarantee — happiness. We’ll leave it up to you to decide which is more likely.

However, here’s a situation where insure has to be used: 

“Sometimes I even go to Fun parks and ride in the jet cars when they race on the edge of town at midnight and the police don't care as long as they're insured.”

― Ray Bradbury, Fahrenheit 451

Of course, there are probably a lot more examples of insure being used in literature, but for some reason, readers aren’t in the habit of noting down quotes about insuring things.

Insure → insurance

As mentioned, it's more common to see insure in its noun form, insurance. You can check whether you should use insure or ensure (or assure) in a sentence by converting between the noun and verb form:

For example:

When she bought the house, she signed an insurance.

When she bought the house, she signed an ensurance.

When she bought the house, she signed an assurance.

Only the sentence with insurance makes sense since “ensurance” isn’t an actual word and you can’t sign an assurance. Conclusion: you have to use insure if you want to use a verb in this context.

When she bought the house, she insured it.

Use assure to remove doubt or express confidence

Assure is often the annoying third wheel in the debate over ensure and insure. With its slightly different pronunciation, it may not be a direct homophone, but it’s still similar enough in meaning and usage to cause confusion. So let’s make sure to iron out all the wrinkles while we’re at it. 

To assure is to say something with confidence, to inform positively, to remove doubt, or even to offer comfort (or reassurance). But, as you may know, people say all sorts of things without being able to back it up or guarantee it, so the cynic might be compelled to point out that assuring something doesn’t necessarily mean it will come true, like ensuring might. 

Here are some examples of assure used in sentences:

Her boyfriend assured her he had not cheated when, in fact, he had been unfaithful for months.

I assure you, we’re doing everything we can to save your husband.

My mom assures me that I’m her favorite child. But I’m her only child.

Examples of assure from literature

The inherently insecure nature of human beings means that you’ll come across many instances in literature where characters are seeking assurance or want to assure others.

Here are some of our favorite examples:

“It was one of those rare smiles with a quality of eternal reassurance in it, that you may come across four or five times in life. It faced—or seemed to face—the whole eternal world for an instant, and then concentrated on you with an irresistible prejudice in your favor. It understood you just as far as you wanted to be understood, believed in you as you would like to believe in yourself, and assured you that it had precisely the impression of you that, at your best, you hoped to convey.”

― F. Scott Fitzgerald, The Great Gatsby

“Deep grief sometimes is almost like a specific location, a coordinate on a map of time. When you are standing in that forest of sorrow, you cannot imagine that you could ever find your way to a better place. But if someone can assure you that they themselves have stood in that same place, and now have moved on, sometimes this will bring hope.”

― Elizabeth Gilbert, Eat, Pray, Love

“Go to bed, you fool," Calcifer said sleepily. "You're drunk."

"Who, me?" said Howl. "I assure you, my friends, I am cone sold stober."”

― Diana Wynne Jones, Howl’s Moving Castle

Assure → assurance

You can do the same test with assurance as we did with insurance:

Her parents' assurance told her she was doing the right thing.

Her parents’ insurance told her she was doing the right thing.

Her parents’ ensurance told her she was doing the right thing.

Again, the only sentence that makes sense is the one with assurance, since insurances can’t really speak and generally don’t get involved in questions of right or wrong, and, again, “ensurance” is not a real word. Thus, you need to use the verb assure if you want to rewrite the sentence:

Her parents assured her she was doing the right thing.

If you find this process of noun-to-verb conversion too tiresome and are still having trouble keeping these verbs apart, you can use memory tricks to remember which to use and when.

Memory tricks to get it right 

Telling ensure, insure, and assure apart can be tricky, especially since they’re so closely related to each other. To help make sure you always get it right, here’s our favorite trick to remember the difference:

A sport metaphor

Our preferred way to remember the difference between ensure, insure and assure is to use metaphors or short stories that encapsulate both the meaning of the three verbs, and helps you create memory hooks!

The best memory hooks are once you create yourself and which hold particular significance to you, but here's an example we created which you might want to use:

🏒 Mark is an ice hockey player. He trained all summer to ensure he’d be in shape for the upcoming season. But in the first game, he got badly injured. He will have to undergo an expensive surgery. Luckily he’s insured, but his morale is down. His coach assures him that rehabilitation will get him back in no time.   

💡Psst. You don’t have to use sports as a metaphor; the trick is to come up with a short snippet or story that helps you create memory hooks that show the nuance of the three words. The more the story or metaphor relates to your own life and interest, the better.

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We hope this article helps you rest assured that you know the difference between these verbs. Or why not hire an editor who can help you?