Choosing between mistakenly and mistakingly can be confusing because both forms appear in written English. They look similar, contain the same basic word, and seem to follow familiar patterns for forming adverbs. However, they do not have the same level of acceptance in everyday modern writing.
For most American English readers and writers, mistakenly is the better choice. It is the established, familiar form used to describe an incorrect belief, an action performed by mistake, or a decision based on an error.
The word mistakingly also appears in dictionaries and published writing. Therefore, it would be inaccurate to say that it has never existed or that it is impossible to understand. The main difference concerns ordinary usage and editorial preference, not a clear difference in meaning.
This guide explains when to use each form, why people confuse them, and how to choose the more natural wording for school assignments, professional emails, reports, and everyday communication.
Quick Answer
Mistakenly is the recommended spelling in modern American English. It means wrongly, incorrectly, or by mistake.
Examples:
- I mistakenly sent the email to the wrong person.
- She mistakenly believed the store was still open.
- The payment was mistakenly charged to another account.
Mistakingly is a rare, historically recorded form that can also convey the idea of acting or thinking erroneously. However, it is much less familiar to most modern readers.
For normal writing, choose mistakenly. You generally do not gain a different meaning or a useful grammatical distinction by choosing mistakingly instead.
Why People Confuse Them
The confusion begins with the word mistake. English uses several related forms, including mistake, mistaken, and mistaking. Because these forms are connected, a writer may assume that adding -ly to either mistaken or mistaking should produce an equally natural adverb.
That assumption seems reasonable. Many English adverbs end in -ly, and their formation can depend on the adjective or word form used as the base. However, familiar word-building patterns do not guarantee that every possible form will be equally common or appropriate.
Consider these examples:
- Mistakenly: He mistakenly identified the caller.
- Mistakingly: He mistakingly identified the caller.
Both sentences communicate an incorrect identification. Nevertheless, the first sounds more natural in contemporary American writing because mistakenly is the established choice.
Another source of confusion is exposure to older books, historical documents, and occasional modern publications that use mistakingly. Seeing a word in print can make it appear as common as a more familiar alternative. In this case, the existence of the rarer form does not make the two choices equally suitable for everyday writing.
The practical lesson is simple: recognize that mistakingly exists, but prefer mistakenly when you want clear, conventional wording.
Key Differences At A Glance
The two forms are closely related in meaning, but their usage differs in familiarity and practical suitability.
| Feature | Mistakenly | Mistakingly |
|---|---|---|
| Grammatical role | Adverb | Adverb |
| General meaning | Wrongly or by mistake | Erroneously or wrongly |
| Modern US usage | Standard and familiar | Rare and less familiar |
| Everyday writing | Recommended | Usually avoid |
| Formal writing | Natural and appropriate | May seem unusual |
| Meaning distinction | No established separate meaning | No established separate meaning |
The main distinction is conventional usage. Mistakenly is the dependable choice in modern American English, while mistakingly is an uncommon alternative.
Neither form should be assigned a separate meaning simply to explain why the spellings differ. Their meanings overlap substantially, and the stronger recommendation for mistakenly comes from its established use.
Are They the Same Word?
Mistakenly and mistakingly are related adverbs used to express the idea of being wrong or making an error. They are not best explained as two words with clearly separate meanings.
The difference is primarily one of usage. Mistakenly is the familiar form that readers normally expect in current English. Mistakingly is an attested but uncommon form.
For example:
- The employee mistakenly entered the wrong address.
- The employee mistakingly entered the wrong address.
The intended message is essentially the same in both sentences. The first sentence is preferable because it follows conventional modern usage and is less likely to distract the reader.
The same applies when describing a belief rather than an action:
- We mistakenly assumed the deadline had changed.
- We mistakingly assumed the deadline had changed.
Both versions express an incorrect assumption, but mistakenly remains the more natural choice.
It is also important to distinguish the adverb mistakingly from the verb form mistaking. In a sentence such as “She was mistaking his silence for agreement,” the word mistaking is part of the verb phrase. It does not serve as an alternative spelling of the adverb mistakenly.
Understanding this distinction helps writers avoid confusing related word forms with competing spellings.
US vs UK Preference
For both American and British English, mistakenly is the familiar, established choice in ordinary writing. There is no clear basis for treating mistakingly as the standard British spelling and mistakenly as the standard American spelling.
This is important because many English spelling differences follow recognizable regional patterns. Words such as color and colour, for example, differ according to established spelling conventions. The comparison between mistakenly and mistakingly does not follow that same pattern.
American writers should use mistakenly in schoolwork, workplace communication, news writing, and general publications. British writers can use it as well.
A publisher may have its own editorial rules, but that is a matter of individual house style rather than a widely recognized US-versus-UK spelling rule.
The presence of mistakingly in historical or published material should not be taken as evidence of a separate regional standard. When the goal is natural, broadly understood English, mistakenly is the safest choice on either side of the Atlantic.
Which Spelling Should You Use?
Choose mistakenly in almost every ordinary writing situation. It communicates the intended idea clearly and matches the form most readers expect.
Use it in the following contexts:
School assignments: If you are explaining an incorrect answer, belief, or decision, write, “The student mistakenly selected option B.”
Professional emails: If you need to correct an error, write, “I mistakenly attached the earlier version of the report.”
Business communication: If an order or payment was handled incorrectly, write, “The customer was mistakenly charged twice.”
News and informational writing: If a person or organization made an incorrect claim, write, “The statement mistakenly identified the location.”
Everyday messages: If you made a simple error, write, “I mistakenly thought we were meeting tomorrow.”
In each example, the word fits naturally without requiring the reader to stop and consider an unusual spelling.
You may encounter mistakingly in older texts or in writing that preserves an author’s original wording. In such cases, it can be appropriate to retain the original form when quoting or discussing the historical text. That does not mean you need to choose it for your own writing.
When editing a draft, replace mistakingly with mistakenly unless a specific historical, quotation, or editorial reason calls for preserving the less common form.
When One Spelling Looks Wrong
The word mistakingly can look incorrect in modern writing because it is uncommon. A reader may assume it is a typographical error or an attempt to form an adverb from mistaking.
However, calling it universally nonexistent would be too strong. Historical dictionary records and published examples show that the form has been used. The better distinction is between a form that exists and a form that is recommended for ordinary use.
Mistakenly rarely raises the same concern because it is well established and widely recognizable.
Consider this sentence:
“She mistakingly sent the confidential document to the wrong department.”
The meaning is understandable, but the spelling may draw attention away from the message. A more conventional version is:
“She mistakenly sent the confidential document to the wrong department.”
The revised sentence is clearer from an editorial perspective because it uses the familiar form.
This does not mean that every uncommon word is wrong. English contains many rare but legitimate words. Nevertheless, when two forms express the same idea and one is far more familiar, the familiar form is usually the better choice for a general audience.
For students and non-native English learners, using mistakenly also reduces the chance of receiving a correction from a teacher or editor who expects standard contemporary usage.
Common Mistakes (and Quick Fixes)
Writers can avoid confusion by recognizing a few recurring errors.
Mistake 1: Treating both forms as equally common
Incorrect assumption: Both spellings are equally suitable for every modern context.
Quick fix: Use mistakenly as your default. The fact that mistakingly exists does not make it equally familiar or preferable.
Mistake 2: Assuming the forms have different meanings
Incorrect assumption: Mistakenly describes an accidental action, while mistakingly describes an incorrect belief.
Quick fix: Do not invent this distinction. Both forms have been used to express an erroneous action, judgment, or belief. The practical difference is usage preference.
Mistake 3: Confusing mistakingly with mistaking
Incorrect: “I was mistakenly the noise for a warning.”
Correct: “I was mistaking the noise for a warning.”
Also correct: “I mistakenly thought the noise was a warning.”
Quick fix: Use mistaking when the sentence requires that verb form. Use mistakenly when you need an adverb.
Mistake 4: Assuming the less common form is a regional spelling
Incorrect assumption: Mistakingly is British, while mistakenly is American.
Quick fix: Use mistakenly in both American and British English unless a specific publication requires otherwise.
Mistake 5: Replacing a clear word with an unusual one
Less natural: “The manager mistakingly approved the wrong invoice.”
Better: “The manager mistakenly approved the wrong invoice.”
Quick fix: Prefer the familiar form in business, academic, and public-facing writing.
Mistake 6: Correcting historical quotations without considering context
A historical text may contain mistakingly. Automatically changing the spelling in a direct quotation could alter the source wording.
Quick fix: Preserve the original wording when accuracy requires it. In your own explanatory text, use mistakenly.
These corrections help maintain clear writing without overstating the status of the rarer form.
Everyday Examples
The following sentences show how mistakenly works in natural American English. Each example describes an error in an action, belief, judgment, or understanding.
- I mistakenly deleted the file before saving a backup.
- She mistakenly believed the appointment was scheduled for Friday.
- The package was mistakenly delivered to our neighbor’s house.
- We mistakenly assumed that the office would be open on the holiday.
- He mistakenly entered the wrong ZIP code on the application.
- The teacher mistakenly marked the correct answer as incorrect.
- I mistakenly sent the draft to the entire team.
- The bank mistakenly processed the payment twice.
- They mistakenly thought the event had been canceled.
- The website mistakenly displayed an outdated price.
- My friend mistakenly took my jacket after the meeting.
- The report mistakenly identified the year of the incident.
- She mistakenly thought I was criticizing her work.
- The receptionist mistakenly booked two appointments for the same time.
- We mistakenly left the signed form at home.
Each example uses the same familiar pattern: mistakenly modifies an action or describes how an incorrect belief or judgment occurred.
The following examples demonstrate how the rarer form may appear:
- He mistakingly identified the visitor as a customer.
- She mistakingly believed the instructions applied to everyone.
- They mistakingly recorded the wrong date.
These sentences remain understandable, but mistakenly would normally be the preferred replacement in contemporary writing.
A useful editing technique is to read the sentence aloud and substitute “by mistake” or “incorrectly” for the adverb. If the sentence retains its intended meaning, mistakenly will often be a suitable choice.
For instance, “I mistakenly selected the wrong file” can become “I selected the wrong file by mistake.” The second version is equally clear, although it has a slightly different sentence structure.
Dictionary-Style Word Details
Verb
Mistakenly: This is an adverb, not a verb. It modifies an action or describes an incorrect belief, decision, or conclusion. For example, “He mistakenly entered the wrong number.”
Mistakingly: This is also used as an adverb in recorded English, although it is uncommon. It is not a standard verb form. For example, “He mistakingly entered the wrong number” conveys the same general idea but is less natural for most modern readers.
The related verb is mistake. Its forms include mistakes, mistook, mistaken, and mistaking, depending on tense and grammatical structure. These forms should not be confused with either adverb.
Noun
Mistakenly: It is not a noun. The related noun mistake refers to an error or an incorrect action, judgment, or belief.
Mistakingly: It is not a noun either. The rare adverb does not create a separate noun meaning.
For example, “That was a mistake” uses the noun, while “I mistakenly made that choice” uses the adverb.
Synonyms
Mistakenly: Useful alternatives include incorrectly, wrongly, erroneously, and in error. Depending on the sentence, by mistake or accidentally may also fit. These alternatives are not always exact substitutes because they can emphasize different aspects of an error.
Mistakingly: The closest plain alternatives are also incorrectly, wrongly, and erroneously. The rare form does not have a separate set of synonyms based on its spelling.
Antonyms can include correctly, accurately, and properly when the sentence describes an action or judgment that can be performed correctly. The best opposite depends on the context.
Example Sentences
Mistakenly:
- I mistakenly used the old address.
- The customer was mistakenly charged an extra fee.
- She mistakenly thought the meeting began at noon.
- The article mistakenly named the wrong person.
Mistakingly:
- He mistakingly attributed the quote to the wrong author.
- They mistakingly assumed the entrance was on the next street.
- She mistakingly identified the file as the final version.
The first group illustrates the preferred modern form. The second group shows how the uncommon form can be understood in context. For new writing, the second group would normally be edited to use mistakenly.
Word History
Mistakenly: The word is formed from mistaken with the adverb-forming suffix -ly. Its structure is consistent with the way English forms many adverbs from adjectives.
Mistakingly: Historical dictionary records document this form as an adverb meaning erroneously or falsely. Its existence shows that it is not simply an impossible combination of letters. However, its history does not establish it as an equally common modern alternative.
The useful point for present-day writers is not a precise date of origin or a speculative explanation for its decline. It is the difference between historical attestation and current editorial preference.
Phrases Containing
Mistakenly: Common patterns include mistakenly believed, mistakenly assumed, mistakenly identified, mistakenly reported, mistakenly entered, and mistakenly charged. These combinations occur naturally when describing an error in thought, communication, identification, or action.
Examples:
- The form was mistakenly entered twice.
- She mistakenly assumed that permission had been granted.
- The customer was mistakenly charged for a second order.
Mistakingly: The form can appear before verbs such as believed, assumed, identified, and attributed. However, these combinations are uncommon in contemporary general writing. Writers who want a natural, familiar expression should normally use the corresponding phrase with mistakenly.
Neither form has a unique set of phrases that creates a reliable difference in meaning. The choice is primarily about conventional usage.
FAQs
Is it mistakenly or mistakingly?
Mistakenly is the preferred spelling in modern English, especially in American writing. It means wrongly, incorrectly, or by mistake. Mistakingly is a rare, historically attested alternative, but it is less common in everyday writing.
Is mistakingly a real word?
Yes, mistakingly is a recorded English adverb. However, it is uncommon in modern usage. Most writers should choose mistakenly for clearer, more natural communication.
What does mistakenly mean?
Mistakenly means doing something based on an error or believing something that is not correct. For example, “I mistakenly sent the email to the wrong person.”
What is the difference between mistakenly and mistakingly?
The main difference is usage and familiarity. Both forms can express the idea of being wrong, but mistakenly is the established, widely preferred form in contemporary English. They do not have a clear, standard difference in meaning.
Is mistakenly correct in American English?
Yes. Mistakenly is the recommended choice in American English. It is suitable for school assignments, professional emails, reports, articles, and everyday conversations.
Is mistakingly grammatically incorrect?
Not necessarily. Mistakingly is a documented form, but it is rare and may sound unusual to modern readers. In most situations, replacing it with mistakenly is the better editorial choice.
Is mistakenly an adverb?
Yes. Mistakenly is an adverb that describes an incorrect action, belief, or judgment. For example, “She mistakenly entered the wrong address.”
Can I use mistakingly in formal writing?
It is possible, but it is generally better to use mistakenly in formal writing. The familiar form is clearer and less likely to distract readers.
What are some synonyms for mistakenly?
Depending on the sentence, synonyms or alternatives include incorrectly, wrongly, erroneously, and by mistake. The best alternative depends on the context.
How can I remember the correct spelling of mistakenly?
Remember the familiar phrase “a mistaken belief.” Adding -ly to mistaken gives you mistakenly. When describing an action or belief that is wrong, use mistakenly as your default choice.
Conclusion
When comparing mistakenly vs mistakingly, the most practical answer is to use mistakenly in modern American English.
It is the familiar adverb for describing an incorrect action, belief, assumption, or judgment. It fits naturally in academic assignments, professional communication, reports, and everyday messages.
Mistakingly is a rare but historically attested form. It can communicate a similar idea, so it is too strong to claim that the word has never existed. Still, its rarity makes it a less suitable choice for most contemporary writing.
Remember the simplest rule: if you mean “wrongly,” “incorrectly,” or “by mistake,” choose mistakenly unless you have a specific reason to preserve the less common form.
This choice keeps your writing natural, clear, and consistent for a broad American English audience.
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