Mistakingly or Mistakenly: Correct Spelling Explained

Many people get confused when they see these two words. You may have typed mistakingly or mistakenly in an email and stopped to wonder which one is right. It is a common doubt, and you are not alone.

Only one of them is correct in standard English. The right word is “mistakenly.” It means doing something by error or by accident. For example, “She mistakenly sent the message to her boss.”

“Mistakingly” looks logical, but it is not a real word. Most dictionaries do not list it. In this guide, you will learn the correct spelling, its meaning, and easy examples to remember it.

Mistakingly or Mistakenly: What’s the Difference?

There is no difference in meaning. There is only one real word and one spelling error.

Spelling	Correct?	Status
Mistakenly	Yes	Standard adverb in US and UK English
Mistakingly	No	Misspelling, not found in major dictionaries

Both versions try to say the same thing: “by mistake.” But only “mistakenly” is accepted in formal and everyday writing.

Think of it like this. “Mistakenly” is the word. “Mistakingly” is a typo that feels logical, so it keeps spreading.

Is “Mistakingly” a Real Word?

No. “Mistakingly” is not a standard English word. Major dictionaries list “mistakenly” and do not list the other form.

You may still see it online. People publish it in blogs, comments, and captions. That does not make it correct. It only shows how common the slip is.

What professional writing favors

Editors, journalists, and academic writers use “mistakenly” every time. Style guides and spellcheck tools flag “mistakingly” as an error.

If your text is for work, school, or publication, use mistakenly. It protects your credibility.

Why “Mistakenly” Is Correct

The word comes from a simple chain.

• Mistake is the base verb (mistake, mistook, mistaken).
• Mistaken is the past participle. It means wrong or misunderstood.
• Mistaken + -ly gives you mistakenly.

So the adverb is built from “mistaken,” not from “mistaking.” That is why you see the “-en” in the middle.

Compare it with similar words: “hidden” becomes “hiddenly” in rare use, and “forgiven” can become “forgivenly” in poetry. The idea is the same. The participle form takes the “-ly.”

What Does Mistakenly Mean?

“Mistakenly” is an adverb. It describes an action done by error, or a belief that is wrong. It carries two shades of meaning:

• By accident: you did something without meaning to.
• Wrongly: you believed or judged something incorrectly.

It usually sits next to a verb, such as believed, sent, assumed, thought, deleted, or identified.

Example sentences

• She mistakenly poured salt into her coffee.
• He mistakenly believed the meeting was on Friday.
• The clerk mistakenly sent the invoice to the wrong client.
• I mistakenly deleted the file before saving it.
• They mistakenly assumed the store was open.
• The system mistakenly flagged the email as spam.

Notice the pattern. In each sentence, a person or system made an honest error. Nobody did it on purpose.

Mistakenly vs Accidentally

These two words overlap, but they are not identical.

Key difference

Mistakenly points to a wrong belief or wrong judgment. Accidentally points to something that happened without intention, often a physical slip.

Compare them

Feature	Mistakenly	Accidentally
Core idea	Wrong belief or choice	Unplanned event
Typical cause	Misjudgment, confusion	Clumsiness, bad luck
Common verbs	believe, assume, identify, send	drop, spill, hit, delete
Example	He mistakenly thought it was free.	He accidentally dropped the glass.

Some sentences work with both. “She mistakenly sent the email” and “She accidentally sent the email” are both fine. The first suggests she misread something. The second suggests her finger slipped.

Why People Write “Mistakingly”

This error is not random. There are clear reasons behind it.

False pattern matching

The verb is “mistaking.” It feels natural to add “-ly” to it. Many adverbs follow a simple rule: take the root and add “-ly.” The brain applies that rule and lands on “mistakingly.”

But English adverbs often grow from participles or adjectives, not from “-ing” forms. That is the source of the confusion.

Sound causes confusion

Say the word out loud: mis-TAKE-en-ly. The middle sound is soft. Many speakers blur it, so the ear hears something close to “mis-TAKE-in-ly.” Spelling by sound then drifts toward “mistakingly.”

A fast speaker or a writer typing by ear can easily swap the letters.

Why English Uses “Mistakenly” Instead of “Mistakingly”

English borrowed its verb forms from older patterns. “Mistake” is an irregular verb, so its participle is “mistaken,” not “mistaked.” When we need an adverb, we build it on the participle.

This is the same logic you see in other words:

• Broken gives brokenly
• Unknown gives unknowingly (a different pattern, but still tied to the form of the base)
• Mistaken gives mistakenly

The language settled on one form over time. Dictionaries record that form. Speakers learned it. “Mistakingly” never gained ground.

Common Phrases Using “Mistakenly”

You will meet this word in many settings. Some phrases are very common.

Everyday phrases

• mistakenly believed
• mistakenly thought
• mistakenly assumed
• mistakenly identified
• mistakenly sent
• mistakenly deleted
• mistakenly charged
• mistakenly left behind

These pair “mistakenly” with verbs of thinking or doing. That pairing is a good sign you are using it right.

Example in context

“I mistakenly assumed the package had shipped, so I told the customer it was on the way.”

The speaker held a wrong belief and acted on it. That is the classic use.

Incorrect vs Correct Usage

Incorrect	Correct
He mistakingly sent the file.	He mistakenly sent the file.
I mistakingly believed her.	I mistakenly believed her.
The bill was mistakingly doubled.	The bill was mistakenly doubled.
They mistakingly took my bag.	They mistakenly took my bag.
She mistakingly called me John.	She mistakenly called me John.

Quick check: if you see “-aking-ly” in the middle, swap it for “-aken-ly.”

What Dictionaries Say

Trusted dictionaries agree. They list “mistakenly” as an adverb and show it as the standard form. They do not carry “mistakingly” as a separate entry.

Common dictionary treatment

• Part of speech: adverb
• Pronunciation: mis-TAY-kun-lee
• Meaning: by mistake, or in a wrong way
• Related words: erroneously, wrongly, incorrectly, inadvertently
• Opposites: correctly, deliberately

Some entries note two senses: an unintended action, and an incorrect belief or judgment. Both fit the examples earlier in this guide.

Case Study: A Costly “Mistakenly” Error in Business Writing

The following is an illustrative scenario, not a real company.

Imagine a small online store. A support agent writes a refund email to an unhappy customer: “We mistakingly charged you twice, and we apologize.”

The customer notices the odd spelling. The apology feels careless. A screenshot goes up on social media with the caption: “They can’t even spell their own apology.”

The store never lost the sale because of the double charge. It lost trust because of a spelling slip in a message meant to rebuild trust.

Lessons from this scenario:

1. Small errors weaken serious messages.
2. Apologies need extra care, because readers look for sincerity.
3. A quick proofread, or a spellcheck pass, would have caught it.

Mistakenly in Business Communication

In the workplace, “mistakenly” often shows up when explaining an error without blaming anyone harshly. It sounds polite and neutral.

Common uses

• Billing: “Your account was mistakenly charged.”
• Shipping: “The order was mistakenly sent to another address.”
• HR and admin: “The form was mistakenly filed under the wrong name.”
• IT: “The file was mistakenly moved to the archive.”
• Customer service: “We mistakenly listed the wrong price.”

Tone tip: “mistakenly” admits an error while keeping the message calm. It fits apologies, status updates, and incident reports.

Mistakenly in Legal Writing

Legal documents care about intent. Whether an act was a mistake or deliberate can change the outcome.

You may see phrases such as:

• “mistakenly delivered”
• “mistakenly identified the party”
• “mistakenly omitted from the record”

In formal legal drafting, writers sometimes choose erroneously instead. It sounds stricter. But “mistakenly” remains correct and clear, and it is widely used in contracts, notices, and court filings.

One rule applies everywhere: spell it correctly. In a legal setting, even a small spelling slip can look sloppy.

Is “Mistakingly” Ever Acceptable?

In formal writing, no. In casual texting, some people let it slide, but it still reads as an error.

There are only two safe situations for the wrong form:

• You are quoting someone else’s text exactly, and you mark it with [sic].
• You are writing an example of a misspelling, like in this article.

Outside of those cases, choose “mistakenly.”

American vs British English: Is There a Difference?

Good news. There is no regional split here.

US English

American English uses mistakenly. Dictionaries and style guides in the United States treat it as the only standard form.

British English

British English also uses mistakenly. You will see it in UK newspapers, legal texts, and everyday writing the same way.

Region	Spelling
United States	mistakenly
United Kingdom	mistakenly
Canada, Australia	mistakenly

So you do not need to change your spelling based on your audience.

Common Grammar Mistakes Related to Mistakenly

People who stumble on this word often trip on other look-alike words. Here are four of the most common.

Accidently vs Accidentally

Accidentally is the standard spelling. It comes from “accidental” plus “-ly.” Some sources list “accidently” as a rare variant, but most editors treat it as an error. Stick with accidentally.

Definately vs Definitely

Definitely is the only correct form. The base word is “definite,” so the ending stays “-ite.” “Definately” is a spelling error caused by sound.

Judgement vs Judgment

Both spellings exist. Judgment is the usual US form. Judgement is common in British English, although legal writing in the UK often prefers “judgment.” Pick one and stay consistent.

Mistook vs Mistaken

These are two forms of the same verb.

• Mistook is the simple past: “I mistook him for my cousin.”
• Mistaken is the past participle: “I have been mistaken.”

Never write “I have mistook” or “I mistaken him.” Match the form to the sentence.

Verb form	Example
mistake	Don’t mistake silence for agreement.
mistook	She mistook the salt for sugar.
mistaken	You are mistaken about the date.
mistaking	He is mistaking kindness for weakness.

How to Remember the Correct Spelling

A few simple tricks lock this word in.

The easiest trick

Remember: mistaKEN-ly. The word contains “mistaken.” If you can spell “mistaken,” you can spell “mistakenly.” Just add “-ly.”

Pattern shortcut

Ask yourself: Is there a “mistaken” inside this word?

• mistaken + ly = mistakenly ✅
• mistaking + ly = mistakingly ❌

One more memory hook: the correct word has an “e” before the “n.” Think of “e” for error.

Why Search Interest for “Mistakingly or Mistakenly” Keeps Growing

More people search this phrase every year. Here is why.

Spellcheck dependence

Many writers rely on autocorrect. When the tool does not flag a word, they assume it is fine. Some tools flag “mistakingly” and some do not catch it in context, so doubt remains. Writers then turn to search.

Phonetic spelling habits

People spell by sound more than ever, especially while typing fast on phones. The soft middle vowel in “mistakenly” invites errors.

Pattern assumptions

We learn the “verb + -ing + -ly” idea from words like willingly and knowingly. Those are real words, so “mistakingly” looks like one more. That false pattern keeps the search volume high.

Real-World Examples From Daily Use

Here is how the word appears in common places.

Email

• “I mistakenly sent you the old draft. Please use the attached version.”
• “Our team mistakenly scheduled two calls at the same time.”

Texting

• “omg i mistakenly texted my boss instead of my sister 😭”
• “Sorry, I mistakenly left your charger at home.”

Social Media

• “Mistakenly ordered two coffees today. No regrets.”
• “I mistakenly opened the front camera. Never again.”

Even in casual spots, the correct spelling looks cleaner and gets taken more seriously.

Quote Worth Remembering

If “mistaken” is hiding inside the word, you spelled it right.

Keep this line in mind the next time you hesitate.

Mistakingly or Mistakenly

The debate has a clear winner. Mistakenly is correct, and mistakingly is not. The adverb comes from the participle “mistaken,” and every major English dictionary follows that form.

Use “mistakenly” when you mean by accident or wrongly. Use it in emails, reports, essays, posts, and legal notes. It is the same in US and UK English.

Quick Rule Summary

• ✅ Mistakenly is the correct spelling.
• ❌ Mistakingly is a misspelling.
• Build the adverb from mistaken, not mistaking.
• Use it with verbs like believed, sent, assumed, thought, and deleted.
• Choose accidentally for unplanned physical events, and mistakenly for wrong beliefs or wrong choices.
• Spelling is the same in American and British English.

Frequently Asked Questions

Is it mistakingly or mistakenly?

The correct spelling is “mistakenly.” “Mistakingly” is a common misspelling.

Is mistakingly a real word?

No. Standard dictionaries do not list it as a word.

What does mistakenly mean?

It means by mistake, or in a wrong way. For example: “She mistakenly took my umbrella.”

What is the difference between mistakenly and accidentally?

“Mistakenly” suggests a wrong belief or choice. “Accidentally” suggests something that happened without intent.

Why do people write mistakingly?

They add “-ly” to the verb form “mistaking,” or they spell the word by sound.

Is mistakenly used in both American and British English?

Yes. Both use the same spelling.

Is mistakenly a formal word?

It works in both formal and casual writing. In very formal or legal text, “erroneously” is a stricter alternative.

What are synonyms for mistakenly?

Common synonyms are wrongly, erroneously, incorrectly, and inadvertently.

How do I remember the spelling of mistakenly?

Spot the word “mistaken” inside it, then add “-ly.”

Can I use mistakenly at the start of a sentence?

Yes. For example: “Mistakenly, he opened the wrong door.” It is correct, though most writers place it before the verb.

Final Thought

The answer to “mistakingly or mistakenly” is short: mistakenly. Once you see that the word is built from “mistaken,” the confusion fades.

A clean spelling shows care. Whether you are writing a client email, a school paper, or a quick text, take two seconds to check this one. Your readers will trust your words more, and your message will land the way you meant it.