There are a number of words that are often mixed up in writing: effect vs. affect, compliment vs. complement, and others. Here's a problem I've encountered a lot: the confusion of ensure versus insure.

But wait, those two words are the same, right? Well . . . not exactly. Let's look at some definitions and examples.

When to Use Ensure vs Insure

The Connection Between Ensure and Insure

Every time I hear the word “ensure,” I think of the high-protein flavored beverage that I will never drink.

But we're going to use this ingestible product to help you remember how to use ensure. Win-win (kind of).

Both “insure” and “ensure” are verbs. They both derive from the same word meaning “to make sure.” So are they just a spelling variant of the same word?

No. The context can help clarify the difference between insure and ensure and the more distinct meanings for each.

What does Ensure mean?

For example:

Carrie knew that drinking a gallon of milk in an hour would ensure that Simon would experience intense gastrointestinal discomfort, but she didn't make any moves to prevent his performance.

If you've ever watched someone take on the gallon challenge, where a person tries to drink an entire gallon of milk or other beverage all at one time, you're familiar with this scenario.

Participating in the gallon challenge ensures that Simon will not be doing well in an hour or less– his stomach is going to hurt as it processes that much liquid. The rapid consumption ensures he won't feel well.

What does Insure mean?

Insure suggests protecting or securing against a negative outcome.

In this case, achieving the desired outcome will require some work or investment; it's not an easy guarantee. You often insure against something.

It's most commonly used in the context of an insurance policy usually with an insurance company (health, homeowner's, car, life insurance etc.). But it still has uses outside of the realm of policies, deductibles, and financial compensation:

Unbeknownst to Carrie, Simon had two bottles of Pepto-Bismol in his pocket, hoping that they would insure against trouble in his digestive tract.

In this case, Simon has brought some medicinal aids in order to protect his digestive system from undesirable effects. In this broader meaning, he's trying to protect against a stomach ache by taking medicine to counteract it.

Insure Against Grammar Mishaps

The English language can be tricky. But we'll keep posting articles like this to ensure you understand all its ins and outs. Keep reading and practicing in the comments to insure against unfortunate errors in your writing! (See what I did there?)

Need more grammar help? My favorite tool that helps find grammar problems, (ensuring that my grammar is correct) and even generates reports is ProWritingAid. Works with Word, Scrivener, Google Docs, and web browsers. Also, be sure to use our coupon code to get 20 percent off: WritePractice20

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What sets of similar words trip you up? Let us know in the comments!


Take fifteen minutes to write about Simon's decision to partake in the gallon challenge. How successful was his insurance attempt? Has he really ensured his digestive demise?

Post in the Pro Practice Workshop here, so we can be just as grossed out as you are. Be sure to leave feedback on your fellow writers' pieces!

Liz Bureman has a more-than-healthy interest in proper grammatical structure, accurate spelling, and the underappreciated semicolon. When she's not diagramming sentences and reading blogs about how terribly written the Twilight series is, she edits for the Write Practice, causes trouble in Denver, and plays guitar very slowly and poorly. You can follow her on Twitter (@epbure), where she tweets more about music of the mid-90s than writing.

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