Any Day vs Anyday: Which One Should You Actually Use?

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Have you ever typed "swing by anyday" in a message and suddenly wondered whether it should be written as one word or two? You're not alone. Any day vs anyday is a common spelling confusion because English contains many similar-looking words that have evolved into single terms. The good news is that the correct choice is straightforward: "any day" is the standard form.
The Quick Answer
"Any day" is correct and should always be written as two words. It combines the determiner "any" with the noun "day."
"Anyday" is not considered a standard English word. Although you may see it in social media posts, casual messages, usernames, or branding, it is generally treated as a spelling mistake when the intended meaning is "any day."
For example:
[ul]

• Correct: You can visit any day next week.
• Incorrect: You can visit anyday next week.

[/ul]
The same rule applies in both American and British English.
Why Do People Write "Anyday"?
The confusion is understandable because English has many words that look similar.
Consider words such as:
[ul]

• Anyone
• Anything
• Anytime
• Anywhere
• Everyday

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Because several words beginning with "any" have become compounds, people naturally assume that "anyday" should work in the same way.
There are several reasons this mistake appears frequently.
Similarity to "Anytime"
"Anytime" is a legitimate word in many contexts, so writers may assume that "anyday" follows the same pattern.
For example:

You can call me anytime.

But:

You can call me any day.

The two expressions look almost identical, but only the first uses the standard one-word form.
Fast Typing
When people type quickly, especially on phones, spaces can easily disappear. Autocorrect and predictive text can also contribute to unusual spellings.
Casual Online Writing
Social media, texting, and online comments often contain shortened or unconventional spellings. Once a nonstandard form becomes common online, people may begin assuming that it is grammatically correct.
Pronunciation
When spoken quickly, "any day" can sound almost like one continuous word. This can influence how people spell the phrase.
However, pronunciation does not determine whether two words should be combined in writing.
What Does "Any Day" Mean?
"Any day" generally refers to an unspecified day. It means that the exact day has not been chosen, does not matter, or can be selected from several possibilities.
For example:
You can come over any day this week.
This means you are free to choose whichever day works best.
The phrase can be used in several situations.
Flexible Scheduling

We can meet any day that works for you.

Here, "any day" shows that there is flexibility about the meeting date.
Uncertain Timing

The package could arrive any day now.

This means the package might arrive soon, but the exact day is unknown.
General Preference

I would choose homemade food over fast food any day.

In this sentence, "any day" emphasizes a strong preference.
Availability

The office is open any day from Monday through Friday.

The phrase indicates that the option is available on whichever applicable day is chosen.
A Simple Way to Remember the Rule
One useful trick is to compare "any day" with similar expressions such as "any time," "any place," and "any way."
For example:
[ul]

• I can meet you any day.
• I can meet you any time.
• We can go any place you prefer.
• We can solve it any way you want.

[/ul]
These phrases contain separate words because they function as ordinary combinations rather than established single-word compounds.
So if you are unsure, remember:
Any + day = any day
Not:
Any + day = anyday
Any Day vs Everyday
Another major source of confusion is the difference between "any day" and "everyday."
Although they look similar, they have completely different meanings and grammatical functions.
Everyday is a single word used as an adjective. It describes something ordinary, common, or routine.
Example:

These are my everyday shoes.

Here, "everyday" describes the shoes.
Every day, on the other hand, is a two-word phrase meaning "each day."
Example:

I walk to work every day.

Now compare both with "any day":

[th]Phrase[/th] [th]Meaning[/th] [th]Correct Form[/th]
Any day	An unspecified day	Two words
Anyday	Nonstandard spelling of "any day"	Avoid
Everyday	Ordinary or routine	One word
Every day	Each day	Two words

Understanding this distinction makes the spelling much easier to remember.
Common Examples of "Any Day"
Here are some natural examples:
[ul]

• You can call me any day this week.
• We can finish the project any day before Friday.
• I would choose this restaurant over the other one any day.
• She could return any day now.
• Come visit us any day you are free.
• The weather may change any day.

[/ul]
In each example, "any day" remains two separate words.
Where You Might See "Anyday"
Even though "anyday" is not the standard spelling, you may still encounter it online.
It can appear in:
[ul]

• Social media posts
• Text messages
• Usernames
• Brand names
• Informal comments
• Blog posts containing typos
• Marketing slogans

[/ul]
A company or website may deliberately use "Anyday" as part of a brand name. That does not make it the standard grammatical spelling in ordinary English.
The same principle applies to creative usernames and product names. Names can intentionally bend normal spelling conventions.
Should You Ever Write "Anyday"?
For standard writing, it is best to avoid "anyday."
This includes:
[ul]

• School assignments
• Essays
• Business emails
• Reports
• Blog articles
• Professional documents
• Applications
• Formal communication

[/ul]
Even in casual writing, using the correct form is a good habit because small spelling mistakes can easily carry over into professional situations.
If you see "anyday" in an informal conversation, the meaning will usually still be obvious. However, that does not make the spelling grammatically standard.
Any Day in Formal and Informal Writing
The good thing about "any day" is that it works naturally in almost every type of writing.
Informal:

Come over any day this week.

Professional:

Please let me know if any day next week is convenient for you.

Academic:

The experiment may produce different results on any day because environmental conditions can change.

The spelling remains exactly the same regardless of the context.
Final Takeaway
When choosing between "any day" and "anyday," the answer is simple: use "any day."
"Any day" is the standard two-word phrase used to describe an unspecified, flexible, or possible day. "Anyday" may appear online or in branding, but it is not the standard spelling for ordinary English writing.
A quick way to remember it is to think of "any day" alongside phrases such as "any time," "any place," and "any way." Keeping the words separate will help you avoid this common spelling mistake.
If you regularly come across confusing spelling and grammar choices, learning these small distinctions can make your writing clearer, more polished, and more professional. For more practical explanations of common language mistakes, Residence Hexa's Grammar section offers additional guidance.