Flies or Flys: Which One Is Correct?

Flies is usually the correct spelling, while flys is rarely correct, and this single fact answers the query immediately. Many people search for “flies or flys” because English plural rules

and verb forms can be confusing, especially when words end in -y. Is flies the plural of fly? Is flys ever correct? Does the rule change in British or American English? This article solves all these doubts clearly and simply.

You will learn the correct spelling, the history behind it, spelling rules, common mistakes, real-life examples, and professional advice so you can use flies or flys with full confidence in any situation.

Flies or Flys: Quick Answer

Flies is the correct spelling in most cases.

Flies = plural noun of fly (the insect)
Flies = third-person singular verb of fly

Flys is almost always incorrect, except in very rare technical or brand-related uses.

Examples:

The room is full of flies. ✅
She flies to Dubai every month. ✅
❌ Many flys were in the kitchen. (Incorrect)

The Origin of Flies or Flys

Origin of the Word “Fly”

The word fly comes from Old English flēoge, meaning a flying insect. Over time, English developed spelling rules to make plurals and verb forms easier to recognize in writing.

Why “Flies” Replaced “Flys”

In English, when a noun or verb ends in a consonant + y, the y changes to i before adding -es.

fly → flies
cry → cries
try → tries

This rule became standardized in Modern English, which is why flies is correct and flys disappeared from common usage.

Why Spelling Confusion Still Exists

English has many irregular rules
Learners expect simple +s plurals
Auto-correct sometimes hides mistakes

This makes flies or flys a very common search query.

British English vs American English Spelling

There is no difference between British and American English for flies and flys.

British English

Correct: flies
Incorrect: flys

Example:

The garbage attracted many flies.

American English

Correct: flies
Incorrect: flys

Example:

He flies to New York every week.

Comparison Table

Feature	Flies	Flys
British English	✅ Correct	❌ Incorrect
American English	✅ Correct	❌ Incorrect
Grammar standard	Accepted	Not accepted
Everyday usage	Very common	Very rare

Which Spelling Should You Use?

For US Audiences

Always use flies in both writing and speech. Using flys looks like a spelling error.

For UK & Commonwealth Audiences

The rule is the same. Native speakers expect flies only.

For Global & ESL Writing

Stick to flies in all academic, professional, and online content.

Professional advice: If the base word ends in consonant + y, change y to i and add -es.

Common Mistakes with Flies or Flys

Mistake 1: Adding Only “s”

❌ Many flys are around. ✅ Many flies are around.

Mistake 2: Confusing Plural Noun and Verb Form

❌ She flys every weekend. ✅ She flies every weekend.

Mistake 3: Assuming Both Spellings Are Acceptable

Only flies is accepted in standard English.

Flies or Flys in Everyday Examples

Emails

Please close the window; flies are coming in.
He flies to London for work.

News Writing

Warm weather increases the number of flies.

Social Media

Too many flies today 😖

Formal & Academic Writing

The bird flies at high altitude.

Grammatical Roles of “Flies”

As a Plural Noun

One fly → many flies

Example:

The kitchen was full of flies.

As a Verb (Third-Person Singular)

Used with he, she, it in present tense.

Example:

She flies every Friday.

Is “Flys” Ever Correct?

In standard English, flys is not correct.

Rare exceptions:

Technical codes
Brand names
Scientific labels

These cases do not apply to everyday writing.

Comparison Table: Flies vs Flys

Aspect	Flies	Flys
Plural of fly	✅ Yes	❌ No
Verb form	✅ Yes	❌ No
Standard English	Correct	Incorrect
Professional writing	Recommended	Avoid

Flies or Flys: Google Trends & Usage Data

Search data shows that “flies or flys” is a highly searched grammar question.

Popular Countries

United States
United Kingdom
India
Pakistan
Australia

Why People Search This

Unclear plural rules
ESL learning
Frequent daily usage

Usage Insight

Online books, news, and academic writing use flies almost exclusively. Flys appears mainly in spelling errors.

FAQs About Flies or Flys

Is “flies” the plural of fly?

Yes. Flies is the correct plural form.

Is “flys” ever acceptable?

No, not in standard English.

Why does fly change to flies?

Because words ending in consonant + y change y to i before adding -es.

Is this rule the same in US and UK English?

Yes. Both follow the same rule.

What about words like “boys”?

Boy ends in a vowel + y, so it becomes boys, not boies.

Can “flies” be a verb?

Yes. It is the third-person singular form of fly.

Does pronunciation change?

No. Only the spelling changes.

Conclusion

The confusion between flies or flys comes from misunderstanding how English handles words ending in -y. In correct, standard English, flies is the proper form for both the plural

noun and the present-tense verb. The spelling flys is almost always incorrect and should be avoided in writing, exams, emails, and professional content.

This rule does not change between British and American English, which makes it easier to remember. Once you know that consonant + y changes to -ies, you can apply the same logic

to many other words like cries, tries, and replies. Using flies correctly improves clarity and instantly makes your writing look more polished and professional.

If you remember one thing, remember this: fly becomes flies, never flys. With this guide, examples, tables, and FAQs, you now have a complete and confident answer to the question.