Any Day vs. Anyday: Which One Is Correct?

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English has many small word combinations that can cause surprisingly big confusion. One common example is “any day” vs. “anyday.” Because English contains many words that have developed from two separate words into one, it is understandable that writers sometimes wonder whether “anyday” should be written as a single word. However, in standard English, the correct form is “any day.”

The two-word expression is widely used in everyday conversations, professional writing, academic work, emails, and online content. If you want to improve your Grammar, understanding this simple distinction can help you avoid a common spelling and word-usage mistake. “Anyday” may appear in casual posts or informal messages, but it is generally treated as a nonstandard form.

Any Day vs. Anyday: The Quick Answer​

The correct form is “any day”, written as two separate words.

For example:

• I can visit you any day this week.
• We can arrange the meeting any day after Monday.
• The package could arrive any day now.
• You can call me any day if you need help.

The form “anyday” is generally not recommended in standard English. Major usage references and English-learning resources consistently recommend keeping “any” and “day” separate.

What Does “Any Day” Mean?​

“Any day” is a phrase made up of the determiner “any” and the noun “day.” It normally refers to an unspecified day or one day from a range of possible days.

For example, if someone says, “You can visit any day,” they mean that the visitor does not have to choose one particular day. Monday, Tuesday, Wednesday, or another suitable day may work.

Consider these examples:

• You can submit the form any day this week.
• She is available any day after three o’clock.
• We can travel any day next month.
• Choose any day that works for you.

In each sentence, “day” remains a normal noun, while “any” describes the choice or possibility. There is therefore no reason to combine the two words.

Why Is “Anyday” Usually Incorrect?​

The confusion comes partly from the fact that English does contain many compound words. Some expressions that originally consisted of separate words eventually became accepted as single words. This can make it tempting to assume that “anyday” should work in the same way.

However, English does not follow one universal rule for combining words. Some combinations become standard compounds, while others remain separate phrases.

“Any day” belongs to the second category in standard English. Writing it as “anyday” is generally considered nonstandard, particularly in formal, academic, business, and edited writing. Grammar and style references commonly recommend using the two-word form.

Any Day in Everyday Sentences​

One of the easiest ways to understand the correct usage is to see “any day” in different situations.

Talking About Availability​

When you are available on multiple possible days, use “any day.”

For example:

• I am free any day this week.
• You can come over any day after Friday.
• The doctor has appointments available any day next week.

Here, “any day” means that there is flexibility about which day is selected.

Talking About an Expected Event​

“Any day” can also describe something that may happen soon.

For example:

• The results could be announced any day now.
• The baby is expected any day now.
• Our new furniture should arrive any day.

The phrase “any day now” is especially common. It means that something is expected to happen soon, although the exact time is uncertain.

Expressing Preference​

“Any day” can also be used when expressing a strong preference.

For example:

• I would choose tea over coffee any day.
• She would pick the blue dress any day.
• I would rather walk than wait for a bus any day.

In these examples, “any day” works as part of an informal expression meaning something like “under any circumstances” or “whenever given the choice.”

Any Day vs. Everyday​

A major reason people make the “anyday” mistake is confusion with “everyday.” Although the two expressions look similar, they do not follow exactly the same pattern.

Every day is written as two words when it means “each day.”

Example:

• I exercise every day.
• She reads every day.
• They go to work every day.

However, everyday is a single word when it functions as an adjective meaning ordinary, usual, or common.

Examples include:

• These are my everyday shoes.
• Stress is an everyday problem.
• We use everyday language in the conversation.

So, “every day” and “everyday” both exist, but they have different grammatical functions. This does not mean that “anyday” is automatically a correct compound. In standard English, the correct form remains “any day.”

Any Day vs. Anytime​

Another source of confusion is the word “anytime.” In many varieties of English, “anytime” is an accepted single-word adverb meaning “at any time.”

For example:

• You can call me anytime.
• Come by anytime.
• I can help you anytime.

However, “any day” has not developed the same standard single-word form. This is an important reminder that you cannot always create a new compound word simply by copying the pattern of another expression.

For instance:

• any day ✓
• anytime ✓
• anyway ✓
• anyone ✓
• anyday ✗ in standard usage

The English language contains many irregular patterns, so learning each expression based on its established usage is often the safest approach.

Common Mistakes With Any Day​

Here are some examples of mistakes you may encounter:

Incorrect: I will call you anyday.

Correct: I will call you any day.

Incorrect: The package should arrive anyday now.

Correct: The package should arrive any day now.

Incorrect: You can choose anyday next week.

Correct: You can choose any day next week.

Incorrect: I would pick this restaurant anyday.

Correct: I would pick this restaurant any day.

The important point is that the meaning does not require “any” and “day” to be joined together.

How to Remember the Correct Form​

A simple memory trick can make this rule easier.

Think of “any day” as meaning “any particular day.” If you can imagine choosing one day from several possible days, keep the words separate.

For example:

Choose any day that suits your schedule.

You are choosing one day from several possibilities. Therefore, “any day” is correct.

Another useful trick is to compare it with “every day.” When “day” refers to an actual day or days on a calendar, the two words are normally kept separate.

• I work every day.
• I can work any day.
• We meet every day.
• We can meet any day.

This comparison can help prevent the common mistake of automatically turning “any day” into “anyday.”

Is “Anyday” Ever Used?​

You may occasionally see “anyday” online, especially in social media posts, comments, text messages, or other informal writing. Some people use it casually, and examples can be found in real-world writing. However, seeing a form used does not necessarily mean it is preferred in standard English.

If you are writing an essay, business email, website article, school assignment, application, report, or other formal material, “any day” is the safer and standard choice.

Even in casual writing, using the standard form is useful because it avoids unnecessary questions about correctness.

Any Day: Examples for Better Understanding​

Here are several natural examples:

1. I can meet you any day this week.
2. The delivery should arrive any day now.
3. You can choose any day for your appointment.
4. She is willing to help any day.
5. We could leave any day after the weekend.
6. I would choose this option any day.
7. The weather may improve any day now.
8. You can contact our office any day during business hours.
9. He could return any day.
10. I would rather stay home any day than drive in heavy traffic.

Notice that “any day” remains two words in every example.

Final Verdict: Any Day or Anyday?​

The answer is straightforward: “any day” is the standard and preferred form.

Use any day when you mean an unspecified day, one possible day from a range of days, or when using expressions such as “any day now” and “any day of the week.”

Avoid anyday in formal and standard English because it is generally considered a nonstandard spelling. While you may encounter it in informal online writing, it is not the form you should choose when accuracy and professionalism matter.