Flys vs Flies: Which Is Correct? The Simple Answer

Have you ever typed flys or flies and wondered which spelling is correct? You’re not alone. These two forms look similar, but only one is normally correct in standard English. The confusion usually happens because fly can be both a noun and a verb, and its plural or third-person forms change depending on how it is used.

In this guide, we’ll explain flys vs flies in simple terms, show you the correct spelling, and give you practical examples. If you’re writing an email, school assignment, blog post, or everyday message, you’ll know exactly when to use flies and why flys is usually a spelling mistake.

Quick Answer:

Flies is the correct standard English spelling in almost every situation.

• Flies can be the plural of fly: “There are several flies in the kitchen.”
• Flies can also be the third-person singular form of the verb fly: “The bird flies over the trees.”
• Flys is generally incorrect in standard English.

So, if you’re choosing between flys or flies, use flies.

What Does “Flies” Mean?

The word flies has two common uses in English.

1. “Flies” as the plural of “fly”

When fly refers to the small flying insect, its plural form is flies.

For example:

• One fly is sitting on the window.
• Two flies are sitting on the window.
• The kitchen has too many flies.
• I saw several flies near the garbage.

Notice the spelling change from fly to flies.

2. “Flies” as a verb

Flies is also used when talking about one person, animal, or thing that moves through the air.

Examples:

• The eagle flies high above the mountains.
• A bird flies across the sky.
• The airplane flies over the city.
• Time flies when you are having fun.

Here, flies is the third-person singular form of the verb fly.

Why Is “Flys” Incorrect?

The confusion comes from a common English spelling rule.

When a word ends in a consonant followed by y, the y often changes to i before certain endings are added.

For example:

• fly → flies
• try → tries
• cry → cries
• carry → carries
• study → studies

Because fly ends in a consonant (l) followed by y, its plural or third-person singular form becomes flies, not flys.

Therefore:

❌ flys
✅ flies

This is one of those English spelling patterns that becomes much easier once you recognize the rule.

Fly vs Flies: What Is the Difference?

The difference is mainly grammatical.

Word	Meaning/Use	Example
fly	Singular noun	I saw a fly on the wall.
flies	Plural noun	There are flies in the room.
fly	Base verb	Birds fly south in winter.
flies	Third-person singular verb	The bird flies south.
flys	Usually incorrect spelling	❌ The bird flys away.

A useful way to remember this is:

One fly → many flies
I fly → he/she/it flies

Examples of “Flies” as a Noun

When flies means more than one insect, it is a plural noun.

Here are some natural examples:

1. The flies are attracted to the food.
2. We need to keep the windows closed because of the flies.
3. Several flies were buzzing around the kitchen.
4. The farmer used a screen to keep flies away from the animals.
5. I noticed a few flies near the trash can.
6. The restaurant takes precautions to prevent flies from entering.
7. The warm weather brought more flies into the house.

In each sentence, flies refers to multiple insects.

Examples of “Flies” as a Verb

When flies is a verb, it describes what one subject does.

Examples:

1. The butterfly flies from flower to flower.
2. The bird flies across the lake.
3. My brother flies to London tomorrow.
4. The plane flies above the clouds.
5. The kite flies beautifully in the wind.
6. Time flies when you’re enjoying yourself.
7. The eagle flies over the valley.

A quick grammar test can help: if the subject is he, she, or it, you may need flies.

For example:

• I fly.
• You fly.
• We fly.
• They fly.
• He flies.
• She flies.
• It flies.

Common Mistakes With Flys and Flies

The most common mistake is simply adding s to fly without changing the y.

Mistake 1: Using “flys” as the plural

❌ There are many flys in the house.

✅ There are many flies in the house.

Mistake 2: Using “flys” as a verb

❌ The bird flys over the tree.

✅ The bird flies over the tree.

Mistake 3: Confusing “flies” with “fly’s”

These are different forms.

Flies is usually a plural noun or verb.

Fly’s is a possessive form or a contraction in certain contexts.

For example:

• The flies are everywhere.
• The fly’s wings are damaged.

In the second sentence, fly’s means the wings belong to one fly.

The Spelling Rule Behind “Fly → Flies”

Understanding the spelling rule can prevent similar mistakes with other words.

For many words ending in a consonant + y, change y to i and add -es.

Examples:

• baby → babies
• city → cities
• lady → ladies
• party → parties
• story → stories
• country → countries
• fly → flies

However, if a word ends in a vowel + y, the y usually stays.

For example:

• boy → boys
• toy → toys
• day → days
• key → keys
• play → plays

So compare:

fly → flies
boy → boys

That small distinction explains why flys is not the standard spelling.

Is “Flys” Ever Correct?

For ordinary English writing, flys should be treated as incorrect.

You may occasionally encounter unusual uses of flys in specialized names, brands, usernames, informal writing, or other nonstandard contexts. However, these exceptions do not change the normal English spelling rule.

If you are writing an article, essay, email, school assignment, or professional document, use flies.

American vs British English: Flys vs Flies

There is no meaningful American vs British spelling difference between flies and flys.

Both American English and British English use:

• fly as the singular noun
• flies as the plural noun
• fly as the base verb
• flies as the third-person singular verb

For example:

American English:
“The bird flies across the sky.”

British English:
“The bird flies across the sky.”

The spelling remains the same.

Some English words have different American and British spellings, such as color/colour or traveling/travelling, but flies is not one of them.

How to Remember “Flies” Easily

If you often forget whether to write flys or flies, try this simple memory trick:

A fly can become many flies.

Think:

fly + es → flies

You can also connect it with familiar words:

• cry → cries
• try → tries
• fly → flies

Another useful trick is to remember that “flys” looks incomplete because the spelling rule changes the final y to ie before the s sound.

Flys vs Flies in Everyday Sentences

Here are some quick examples to make the difference crystal clear:

• ❌ The bird flys away.
  ✅ The bird flies away.
• ❌ There are three flys on the wall.
  ✅ There are three flies on the wall.
• ❌ She flys to New York every month.
  ✅ She flies to New York every month.
• ❌ The flys are annoying.
  ✅ The flies are annoying.
• ❌ Time flys when you’re having fun.
  ✅ Time flies when you’re having fun.

FAQs

Is “flys” a correct word?

In standard English, flys is generally not correct. The correct form is flies, whether you mean multiple insects or the third-person singular form of the verb fly.

Is it “flies” or “flys”?

The correct spelling is flies. For example, “The bird flies away” and “There are many flies outside.”

Why does fly become flies?

Because fly ends in a consonant followed by y. When the plural or third-person singular ending is added, the y changes to i, producing flies.

What is the plural of fly?

The plural of fly, when referring to the insect, is flies.

Example: “There were several flies near the window.”

Is “the bird flys” correct?

No. The correct sentence is “The bird flies.” The subject “bird” is singular, so the third-person singular form of fly is flies.

Is “flies” only used for insects?

No. Flies can refer to multiple insects, but it can also be the third-person singular form of the verb fly.

Example: “The plane flies every morning.”

Is “flies” the same in American and British English?

Yes. Both American and British English use flies. There is no standard spelling difference between the two varieties.

How can I remember the spelling of flies?

Remember the pattern fly → flies, just like try → tries and cry → cries. The final y changes to ie.

Summary:

When deciding between flys vs flies, the answer is straightforward: flies is the correct standard English spelling. It can be the plural of the noun fly, as in “There are flies in the kitchen,” or the third-person singular form of the verb fly, as in “The bird flies across the sky.”

The spelling flys is normally a mistake caused by simply adding s to the word fly. Remember the consonant + y spelling rule: fly becomes flies. This same pattern appears in words such as try → tries, cry → cries, and study → studies. The rule is the same in both American and British English.

Actionable Takeaway

Whenever you see yourself typing flys, stop and check the sentence. In standard English, you almost certainly need flies.

Easy rule to remember:

fly → flies
one fly → two flies
the bird flies

Get this simple pattern right, and you’ll avoid one of the most common spelling mistakes involving words that end in -y.