Mistakingly or Mistakenly: Correct Spellings in 2026? 

When you’re deciding between “mistakingly or mistakenly,” the correct choice for most modern English writing is “mistakenly.” It means doing something by mistake, incorrectly, or because you believed something that wasn’t true. For example, you might say, “I mistakenly deleted the file” or “She mistakenly thought the meeting was tomorrow.” The word works naturally in casual conversations, academic writing, emails, and professional communication.

Although “mistakingly” may look like a logical form of the word mistake, it’s rarely used in contemporary English. It is an attested word, so it isn’t completely imaginary or impossible. However, most readers will find “mistakenly” more familiar, natural, and polished. Using the common form also helps your writing sound confident rather than unusual or forced.

So, when in doubt, choose “mistakenly.” It’s the standard option for expressing an action done in error. Remembering the phrase “by mistake” can help you connect it with “mistakenly” and avoid unnecessary confusion in your writing.

What Does Mistakenly Mean?

The word mistakenly is an adverb that means:

Doing something incorrectly because of a mistake, misunderstanding, or wrong belief.

It describes an action that happens accidentally or unintentionally.

The word comes from the adjective mistaken, which means incorrect, wrong, or based on a misunderstanding.

For example:

• “He was mistaken about the meeting time.”
• “She made a mistaken assumption.”
• “They mistakenly believed the store was closed.”

The structure is:

Mistaken + ly = mistakenly

This pattern is common in English.

Similar examples include:

Adjective	Adverb
accidental	accidentally
intentional	intentionally
incorrect	incorrectly
mistaken	mistakenly

The adverb form tells the reader how an action happened.

Consider these two sentences:

Incorrect:

I mistake opened the file.

Correct:

I mistakenly opened the file.

The second sentence clearly explains that opening the file was not intentional.

Mistakenly Definition and Examples in Everyday Writing

The easiest way to understand mistakenly is to replace it with phrases like:

• by mistake
• accidentally
• unintentionally
• incorrectly
• in error

For example:

“I mistakenly took your jacket.”

This means:

“I took your jacket by mistake.”

The action happened, but the person did not intend to do it.

Here are more examples:

Daily Life Examples

Wrong delivery

“The package was mistakenly delivered to my neighbor.”

The delivery happened, but the address or handling was incorrect.

Wrong message

“I mistakenly sent the email before finishing it.”

The sender made an accidental error.

Wrong assumption

“She mistakenly thought the appointment was tomorrow.”

Her belief was incorrect.

Workplace Examples

Professional communication often requires accuracy. A small spelling mistake can affect credibility.

Examples:

“The invoice was mistakenly created with the wrong amount.”

“The report mistakenly included outdated information.”

“The employee mistakenly attached the previous version of the file.”

In business writing, mistakenly sounds clear, professional, and natural.

Read More: Poopy or Poopie? Learn the Right Choice Today (2026)

Academic Writing Examples

Students and researchers often use the word when explaining errors:

“The data was mistakenly recorded during the experiment.”

“The article mistakenly referred to the older study.”

The word helps explain that the error was unintentional.

The Main Difference

The confusion between these two words happens because they look almost identical.

Here is the simple comparison:

Word	Usage	Meaning	Recommendation
Mistakenly	Standard English	By mistake or incorrectly	Use this
Mistakingly	Rare and nonstandard	Intended to mean by mistake	Avoid in normal writing

The important point is that mistakenly is the established form used by modern English speakers, editors, and professional writers.

Although “mistakingly” may seem logical, it does not function as the preferred adverb.

English contains many words that cannot be predicted only by rules. A word may look like it should exist, but common usage decides whether it becomes accepted.

Think of language like a road system. Some roads look like they should connect, but only the roads people actually use become the main routes.

Is Mistakingly a Real Word?

The question “Is mistakingly a word?” is more complicated than simply saying yes or no.

The term mistakingly appears occasionally in informal writing. People create it because they follow a common pattern:

Verb + ing + ly

Examples:

• surprising → surprisingly
• interesting → interestingly
• confusing → confusingly

So someone may think:

mistake → mistaking → mistakingly

The logic seems understandable.

However, standard English does not recognize mistakingly as the normal adverb form for “by mistake.”

The accepted form developed from:

mistaken → mistakenly

This happens because the meaning focuses on being mistaken, not actively mistaking something.

Compare:

Mistaking
means the act of making a mistake or confusing one thing with another.

Example:

“I am mistaking the two names.”

This means the person is currently confusing the names.

Mistakenly
means an action happened because of a mistake.

Example:

“I mistakenly wrote the wrong name.”

The difference is small but important.

Why People Confuse 

English spelling confusion often happens because words share similar roots.

The word mistake creates several related forms:

Word	Type	Meaning
mistake	noun/verb	an error or to make an error
mistaken	adjective	incorrect or wrong
mistaking	verb form	confusing one thing with another
mistakenly	adverb	by mistake

The tricky part is that both mistaken and mistaking come from the same root.

Imagine two branches growing from the same tree. They look connected, but they serve different purposes.

The adjective mistaken describes a state:

“He was mistaken.”

The participle mistaking describes an action:

“He was mistaking the person for someone else.”

The adverb mistakenly describes the manner of an action:

“He mistakenly identified the person.”

Understanding the root makes the spelling easier to remember.

Common Mistakes 

Even people who know the correct spelling sometimes use the word incorrectly.

Here are common errors:

Using Mistakingly in Formal Writing

Incorrect:

“The customer mistakingly received the wrong product.”

Better:

“The customer mistakenly received the wrong product.”

The second version follows standard English usage.

Confusing Mistakenly With Mistaken

Incorrect:

“I was mistakenly.”

Correct:

“I was mistaken.”

or:

“I mistakenly entered the wrong password.”

“Mistaken” describes a person or belief.

“Mistakenly” describes an action.

Using the Wrong Word Form

Incorrect:

“She mistake clicked the button.”

Correct:

“She mistakenly clicked the button.”

The adverb modifies the verb “clicked.”

How to Remember the Correct Spelling 

A simple memory trick helps:

Remember:

Mistaken + ly = mistakenly

The word describes an action caused by being mistaken.

You can also connect it with similar words:

• accidentally
• unintentionally
• incorrectly

All three explain that something happened without the intended result.

A quick test:

Ask yourself:

“Could I replace this word with ‘by mistake’?”

If yes, use mistakenly.

Example:

“I mistakenly locked the door.”

Replace:

“I locked the door by mistake.”

It works.

Side-by-Side Examples

Seeing the words in real sentences makes the difference much easier to understand.

Sentence	Correct or Incorrect	Explanation
I mistakenly deleted the folder.	✅ Correct	The deletion happened by accident.
She mistakenly called the wrong number.	✅ Correct	The action was unintentional.
He mistakingly forgot the appointment.	❌ Not recommended	Use “mistakenly” in standard writing.
They mistakenly believed the store was open.	✅ Correct	The belief was incorrect.
The form was mistakenly filled out.	✅ Correct	The form contained an error.

The key idea is simple:

Use “mistakenly” when you mean “because of a mistake.”

If you are writing an email, article, report, essay, or professional document, mistakenly is the form you should choose.

Mistakenly in Professional and Formal Writing

Words carry impressions. A small spelling choice may seem minor, but professional writing depends on consistency and accuracy.

Imagine reading a business report:

“The payment was mistakingly processed twice.”

The reader can probably understand the meaning. However, the unusual spelling creates a moment of doubt.

Now compare:

“The payment was mistakenly processed twice.”

The sentence feels natural and polished.

In professional environments, clarity matters because your words represent your attention to detail.

You will often see mistakenly used in:

• Business emails
• Legal documents
• Customer support responses
• Research papers
• News articles
• Technical documentation
• Website content

Examples:

Customer support

“Your order was mistakenly delayed due to a system issue.”

Company communication

“The previous announcement mistakenly included outdated information.”

Technical explanation

“The software mistakenly identified the file as corrupted.”

The word helps explain an error without assigning blame.

Mistakenly vs Accidentally: Are They the Same?

Many people wonder whether mistakenly and accidentally mean exactly the same thing.

They are similar, but there is a small difference.

Accidentally

“Accidentally” focuses on something happening unintentionally.

Example:

“I accidentally dropped my phone.”

The event happened without planning.

Mistakenly

“Mistakenly” focuses on an error in judgment, belief, or action.

Example:

“I mistakenly sent the wrong file.”

The person made an incorrect choice.

Both words work in many situations, but the focus changes.

Word	Main Focus	Example
Accidentally	No intention	I accidentally spilled coffee.
Mistakenly	Wrong action or belief	I mistakenly sent the wrong document.

Sometimes either word works:

“She accidentally deleted the photo.”

“She mistakenly deleted the photo.”

Both are understandable.

The second version highlights that she made an error.

Alternatives to Mistakenly

Sometimes you may want to avoid repeating the same word. English gives you several options.

Accidentally

Used for unplanned events.

Example:

“I accidentally pressed the wrong button.”

Unintentionally

A more formal alternative.

Example:

“The comment was unintentionally offensive.”

Incorrectly

Used when something is done in the wrong way.

Example:

“The information was incorrectly entered.”

By Mistake

A simple everyday phrase.

Example:

“I opened your message by mistake.”

In Error

Often used in professional or official writing.

Example:

“The payment was processed in error.”

Here is a quick comparison:

Alternative	Best Used For
Accidentally	Everyday situations
Unintentionally	Formal explanations
Incorrectly	Wrong information or actions
By mistake	Casual conversations
In error	Professional notices

Case Study: Why Correct Word Choice Matters

Consider a company sending a customer announcement.

Version one:

“Your subscription was mistakingly canceled.”

Version two:

“Your subscription was mistakenly canceled.”

The meaning is almost identical. However, the second version sounds more trustworthy.

Why?

Because readers recognize standard patterns quickly. Familiar language feels smoother. Unusual wording forces the brain to stop and analyze.

Good writing removes unnecessary friction.

The goal is not to impress readers with complicated words. The goal is to communicate clearly.

How Grammar Tools Handle Mistakenly and Mistakingly

Modern writing tools often help catch spelling issues. Grammar checkers and word processors usually recognize mistakenly as the standard form.

However, automated tools are not perfect.

A rare word may appear in dictionaries without being the best choice for everyday writing.

That is why context matters.

A tool may tell you a word exists. It does not always tell you whether it sounds natural.

Good writing requires both:

• Correct grammar
• Natural usage

Read More: Referred vs Refered: Correct Spelling Guide for 2026

FAQs

1. Is “mistakenly” the correct word?

Yes. “Mistakenly” is the standard and most widely used adverb in modern English. Use it when you mean that something happened by mistake or because of an incorrect belief.

2. Is “mistakingly” a real word?

Yes, “mistakingly” is an attested word, but it’s uncommon in contemporary English. Most readers expect “mistakenly,” making it the better choice in most situations.

3. What does “mistakenly” mean?

“Mistakenly” means doing something incorrectly, accidentally, or based on a wrong understanding. For example, “I mistakenly called the wrong number.”

4. Can I use “mistakingly” in formal writing?

It’s better to avoid it. Although the word exists, “mistakingly” can sound unusual or awkward in formal writing. “Mistakenly” is clearer and more familiar.

5. Is “mistakenly” an adverb?

Yes. “Mistakenly” is an adverb formed from the adjective “mistaken.” It describes an action performed because of an error or misunderstanding.

6. Which sounds more natural: “I mistakenly did it” or “I mistakingly did it”?

“I mistakenly did it” sounds much more natural. Native speakers commonly use “mistakenly” to describe an action performed by accident or in error.

7. Can “mistakenly” mean “accidentally”?

Sometimes, yes. However, the two words aren’t always interchangeable. “Mistakenly” often suggests an error in judgment or belief, while “accidentally” usually emphasizes that something happened unintentionally.

8. What is an example of “mistakenly”?

You could say, “She mistakenly sent the document to the wrong person.” Here, mistakenly explains that she made an error.

9. Why do people say “mistakingly”?

The confusion probably comes from the verb “mistake” and the familiar adverb-forming ending “-ingly.” However, standard modern usage strongly favors “mistakenly.”

10. How can I remember which word to use?

Connect “mistakenly” with the phrase “by mistake.” If you can naturally say “by mistake,” “mistakenly” will usually be the right choice.

Conclusion

When choosing between “mistakingly or mistakenly,” go with “mistakenly” in almost every modern writing situation. It’s the familiar, natural, and widely accepted choice for describing something done by mistake or based on an incorrect belief.

Although “mistakingly” is an attested word, its rarity makes it a poor choice for most readers. If you want your emails, essays, professional documents, and everyday writing to sound clear and polished, “mistakenly” is the safer option.