Biennially vs. Biannually: What's the Difference?

By Amy Gilmore, updated on August 31, 2023

Do you need to know the difference between 'biennially' vs. 'biannually?' If so, you aren't alone.

Here is the short answer: 

  • 'Biennially' is an adverb that means occurring once every two years. 
  • 'Biannually' is an adverb that means occurring two times a year. 

These adverbs are often used in official business and communications. It is essential that you understand exactly what they mean and how to use them.

So, keep reading!

What is the Difference Between 'Biennially' vs. 'Biannually?'

'Biennially' and 'biannually' are both terms used to describe how often a verb occurs. However, they have different meanings.

  • The first term means every two years
  • The second means two times per year

When and How to Use 'Biennially' vs. 'Biannually'

If you are signing a contract with a payment schedule, there is a big difference between being paid every two years and every six months.

Furthermore, if your boss asks you to schedule a 'biannual' event, they would not appreciate you booking it every two years.

So, here are a few tips for when and how to use these terms:

  • Use 'biennially' when you are talking about an event that occurs every two years.

For example, you might say:

We have a family reunion biennially. We used to do it every year, but it was harder for everyone to attend. 

  • Use 'biennially' to describe a report or review that occurs every two years.

As an example, you could say:

You have to complete the productivity report biennially. Since you only have to do it once every two years, it can be challenging to remember. So, add a reminder to your calendar. 

  • Use 'biennially' for events that last for two years.

As an example, you might hear someone say:

There are some plants that complete their lifecycle biennially.  

  • Use 'biannually' for events that happen twice a year.

So, someone might ask you:

Are you coming to the biannual softball game? We missed you at the last game.

  • Use 'biannually' to describe a payment or publication that occurs twice a year.

For example, I might say:

You have to read this magazine. The articles are so interesting that you won't be able to get enough. It's just too bad that they only publish it biannually. I hate waiting six months for the next issue. 

Definition of 'Biennially': What Does 'Biennially' Mean?

According to the Merriam-Webster Dictionary, the meaning of the adverb 'biennially' means:

  • Happening every two years

It can also mean:

  • Occurring or lasting for two years
  • In reference to plants, a variety that matures, flowers, and dies within two years

'Biennially' Terms and Phrases

Definition of 'Biannually': What Does 'Biannually' Mean?

The same dictionary defines the adverb 'biannually' as:

  • Occurring two times per year

'Biannually' Terms and Phrases

  • Biannually published
  • Biannual event
  • Biannual report

Pronunciation of 'Biennially' vs. 'Biannually'

Now that you understand the difference between 'biennially' vs. 'biannually,' let's look at their pronunciations. Knowing how to pronounce these terms is just as important as knowing their definitions.

So, here is a quick pronunciation guide you can reference. 

  • Use this phonetic spelling to pronounce 'biennially':


  • Use this phonetic spelling to pronounce 'biannually':


As you can see, these terms look similar, but they have very different pronunciations. So, when you are writing, be sure to use the correct spelling, and when you are speaking, ensure that you use the appropriate pronunciation.

Sample Sentences Using 'Biennially' vs. 'Biannually'

Before you leave, read these sample sentences using 'biennially' vs. 'biannually.' They will help you remember the difference between 'biennially' vs. 'biannually' and how to use them.


  • Our organization has a manager's retreat biennially for executives and their families. This year, it is going to be at a ranch near Austin, Texas.
  • You should join our country club. The membership fee is $2,500 biennially, but it is worth every penny.
  • Don't buy plants that flower biennially. They last longer than annuals, but they still die.
  • Perennials flower annually, but they do not die. Annuals and biennials die after one and two years, respectively.
  • We take a family trip biennially. We used to go on vacation annually, but the economy has been slow.


  • In addition to commission on each sale, the sales team receives incentive bonuses biannually.
  • Biannually is not frequent enough to review the sales reports. We should review them monthly.
  • Are you able to travel for work biannually? We have conventions twice a year, usually in New York City and Las Vegas.
  • You need to renew your six-month insurance policy biannually.
  • The charity has events biannually to raise money for their cause.
  • I review my budget biannually to ensure that I am in good shape financially.


  • We bought a boat share. We paid a buy-in to use the boat for a weekend biannually and a week biennially.
  • Biennially is not frequent enough. Can we do it biannually?
  • The mayor used to do a city-wide block party biannually, but after budget cuts, the event had to be rescheduled biennially.
  • Celebrating birthdays biennially is just as ridiculous as celebrating them biannually.

Review of the Difference Between 'Biennially' vs. 'Biannually'

Finally, let's recap the difference between 'biennially' vs. 'biannually': 

  • 'Biennially' is an adverb that means occurring every two years or for two years. 
  • 'Biannually' is an adverb that means occurring twice a year. 
  • You use 'biennially' and 'biannually' to describe the frequency of verbs. 

Even after learning the difference between these terms, they can be challenging to remember. So, if you ever get mixed up, you can always return to this post for a quick review.

You can also use our site to verify the meanings of other terms in the confusing words section. There are hundreds of posts, and each contains a brief and detailed explanation of the difference between the terms it covers and definitions, usage tips, grammar rules, and sample sentences.

Whether you are an aspiring writer or learning English as a second language, they are an incredible resource for expanding your vocabulary and learning how to use terms correctly.

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Written By:
Amy Gilmore
Amy Gilmore is one of the lead freelance writers for She has been a professional writer and editor for the past eight years. She developed a love of language arts and literature in school and decided to become a professional freelance writer after a demanding career in real estate. Amy is constantly learning to become a better writer and loves sharing tips with other writers who want to do the same.

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