once every three years

USAGE SUMMARY

The phrase "once every three years" is correct and usable in written English.
You can use it to describe a specific interval of time that occurs once in three years. For example, "The company holds a large gathering of staff members once every three years."

✓ Grammatically correct

News & Media

Academia

Science

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

I wear this tie, like, once every three years.

Cornell University

Instead, they have a chance only once every three years.

The Economist

Members have a one-person show once every three years.

The New York Times

It is given to an IFS grantee once every three years.

Columbia University

(The least popular: a 3/3 ARM, which adjusts once every three years).

The New York Times

A general assemby of the union is held once every three years.

The Economist

His family visits his father's tomb in Japan once every three years.

The New York Times

Each side may reopen the contract once every three years if market circumstances change "materially".

The Economist

The National Congress, which meets once every three years, is formally the most powerful party institution.

Encyclopedia Britannica

Maybe once every three years or so I raise my voice.

The Guardian - Arts

What's more, stool DNA tests are recommended once every three years, whereas FIT is offered annually.

Nature

Expert writing Tips

Best practice

When using the phrase "once every three years", ensure the context clearly establishes what event or action is being referenced to avoid ambiguity. For instance, specify "The audit occurs "once every three years"" rather than simply stating "It happens "once every three years"".

Common error

Avoid using "once in every three years"; the correct and more natural phrasing is "once every three years". The preposition "in" is redundant and grammatically awkward in this context.

Linguistic Context

The phrase "once every three years" functions as an adverbial phrase of frequency, specifying how often an event or action occurs. As Ludwig AI confirms, this is a correct and usable phrase in English.

Expression frequency: Very common

Frequent in

News & Media

54%

Academia

20%

Science

12%

Less common in

Encyclopedias

2%

Wiki

2%

Formal & Business

2%

Ludwig's WRAP-UP

The phrase "once every three years" is a common and grammatically sound way to express the frequency of an event, indicating it occurs every three years. As Ludwig AI confirms, it’s readily usable in English across a spectrum of contexts. Its versatility is evident in the diverse sources, from academic papers to news reports, where it provides clarity in schedules, regulations, and descriptions of recurring processes. While alternatives like "every three years" or "triennially" offer concision or formality, respectively, sticking to "once every three years" ensures clarity and prevents the use of incorrect variations like "once in every three years".

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

every three years

Omits the initial "once", offering a more concise expression of the same frequency.

triennially

Uses a single word to denote an event occurring every three years, providing a more formal tone.

every third year

Rephrases the interval using ordinal numbers, emphasizing the year in the sequence.

at three-year intervals

Focuses on the span between occurrences, highlighting the duration rather than the repetition.

every 36 months

Converts the period to months for specificity, useful in technical or precise contexts.

a three-year cycle

Emphasizes the cyclical nature of the recurrence, suitable when discussing repeating processes.

every three-year period

Adds redundancy to emphasize the duration, suitable when the time frame needs special highlighting.

on a three-year basis

Highlights the timing from a planning or organizational point of view.

recurring every three years

Specifically indicates the repetition of an event over a three-year timeframe.

every leap triennium

Reference to leap year, for a duration of time every 3 years, where one of those years is a leap year.

FAQs

How can I use "once every three years" in a sentence?

You can use "once every three years" to describe events that recur every three years. For example, "The conference is held "once every three years"" or "The equipment undergoes maintenance "once every three years"".

What is a simpler way to say "once every three years"?

A simpler way to say "once every three years" is "every three years". This alternative omits the "once" for a more concise phrasing while retaining the same meaning.

Is it correct to say "once in every three years" instead of "once every three years"?

No, the correct and more common phrasing is "once every three years". Using "in" is redundant and can sound awkward. Sticking to "once every three years" maintains clarity and grammatical correctness.

How does the meaning of "once every three years" differ from "three times a year"?

"Once every three years" means something happens only one time within a three-year period, whereas "three times a year" means something happens three separate times within a single year. They describe very different frequencies.