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If you’ve ever typed “fourty” and had a nagging feeling something was wrong, you’re not alone. This is one of those misspellings that occurs so often that it’s practically become part of English folklore — the number that breaks the pattern. Most of us expect “four” and “fourteen” to guide us toward “fourty”, but English has other ideas.
The correct spelling is “forty” — without the “u”. It’s been this way for centuries, and it’s the only accepted form in both American and British English. Let me show you why it breaks the pattern, how to make it stick in your memory, and why this particular mistake is so common.
Key Takeaways
- The correct spelling is “forty” — no “u”, no exceptions. Both American and British English use this spelling.
- Why the confusion? — Four (4) and fourteen (14) both contain “u”, so people expect it in forty.
- The historical reason: The “u” was dropped during the phonetic evolution of English; the “-ty” suffix changed pronunciation over time.
- Memory hook: Forty is related to “fortify” (to make strong), not directly to “four”.
- Impact of the error: Using “fourty” signals carelessness and can undermine credibility in formal writing (cheques, legal documents, applications).
The Only Accepted Spelling: Forty
There is no debate here. Forty is the sole correct spelling of the number 40 in English. No dictionary recognizes “fourty”. No major style guide allows it. No English-speaking country uses an alternate spelling.
When you need to write the number 40 in words — whether in a formal document, an essay, a cheque, or a casual email — use “forty”. Every single time.
Real-World Examples
Example 1: I will turn forty next month, and I’m planning a big party.
Example 2: The speed limit on this road is forty miles per hour.
Example 3: She has been working at the company for forty years.
Example 4: It took me forty minutes to drive to the airport.
Example 5: The restaurant can seat approximately forty people at one time.
Why This Mistake Happens So Often
The Pattern Trap
English speakers learn number patterns early: twenty, thirty, and then — by logic — what comes next? If four (4) has a “u”, and fourteen (14) has a “u”, shouldn’t forty (40) also have a “u”?
This is called false analogy in linguistics. We see a pattern and assume it continues. But English isn’t a perfectly logical language. It’s inherited from multiple language families, each with their own rules.
| Number | Spelling | Contains ‘u’? |
|---|---|---|
| 4 | Four | Yes |
| 14 | Fourteen | Yes |
| 24 | Twenty-four | Yes |
| 34 | Thirty-four | Yes |
| 40 | Forty | No ✗ |
As you can see, forty is the exception. Every number containing the digit “4” has a “u” — except the ones ending in -ty (twenty, thirty, forty, fifty, etc.). This is because the “-ty” suffix (meaning “tens”) has a different origin and pronunciation than the individual digit.
Phonetic Change Over Time
The spelling of English words often reflects historical pronunciation changes. In Middle English, the word for 40 was spelled “fourtie” or “fourty”, and it was pronounced with a “u” sound. Over centuries, the pronunciation shifted, and the vowel sound changed. By Modern English, the “u” was dropped from the spelling to match how people actually pronounced it.
This same process affected other “-ty” words. If we look at the root words — “twenty” from “two”, “thirty” from “three”, “forty” from “four” — we can see that the “-ty” suffix has gradually lost the vowel connection to the single-digit number.
Pro tip: Think of “forty” as related to words like “fortify” (to make strong/secure) rather than directly to “four”. This mental connection helps break the false pattern.
Both American and British English: Same Spelling
One common misconception is that “forty” is American and “fourty” might be British (or vice versa). This is completely false. Both American English and British English use the spelling “forty”. There is no regional variant.
If you see “fourty” in published text from any English-speaking country, it’s an error. Period.
Why This Matters in Real Writing
You might think: “Who cares if I spell it ‘fourty’? People will still understand what I mean.” And that’s true — in casual contexts, readability won’t suffer. But in formal writing, this misspelling carries real weight:
- Cheques and financial documents: A cheque written with “fourty” looks unprofessional and could raise questions about the writer’s attention to detail.
- Job applications and resumes: Hiring managers notice spelling errors, and this one is easy to spot.
- Academic papers and essays: It signals carelessness to instructors and readers.
- Professional emails and letters: First impressions matter, and a basic spelling error undermines credibility.
The good news: once you know the rule, it’s trivial to apply consistently.
How to Remember: Three Strategies
Strategy 1: The Digit 4 Rule
Think: “The digit 4 has the ‘u’, but the word ‘forty’ drops it.” This helps break the false pattern.
Strategy 2: Rhyming Memory
Forty rhymes with “sporty”, “saucy”, and “naughty” — none of which have a “u” before the “ty”. So forty fits the pattern of words ending in “-ty”.
Strategy 3: The Fortify Connection
Remember that “forty” is historically related to words like “fortify” and “fort” (a fortified place). This shifts your mental connection away from “four” and toward a different word family.
Common Mistakes and How to Fix Them
✗ Incorrect: I will be fourty years old next year.
✓ Correct: I will be forty years old next year.
Why: The correct spelling is always “forty”, not “fourty”.
✗ Incorrect: The temperature is expected to reach fourty degrees.
✓ Correct: The temperature is expected to reach forty degrees.
Why: Measurements and numbers always use the correct spelling “forty”.
✗ Incorrect: She won the race in under fourty seconds.
✓ Correct: She won the race in under forty seconds.
Why: Time measurements require the correct spelling “forty”.
Sample Dialogue
Teacher: I noticed in your essay you wrote “fourty minutes”. Is that the spelling you meant?
Student: Oh, I think so? Four, fourteen, forty?
Teacher: I see the logic, but no — the correct spelling is “forty” without the “u”. It breaks the pattern.
Student: Why?
Teacher: The “-ty” suffix came from a different word root that evolved differently. So while “four” and “fourteen” keep the “u”, the number “forty” drops it.
Student: Got it. So it’s just one of those English exceptions?
Teacher: Exactly. And now that you know, you’ll remember it!
Quick Quiz
- Write the number 40 in words: __________
- True or False: British English spells it “fourty” while American English spells it “forty”.
- Complete the phrase: “The speed limit is __________ miles per hour.”
- Which spelling is correct: “fourty” or “forty”?
- Write in words: “I bought forty-two apples.” (Is this spelled correctly?)
Answers: 1. Forty · 2. False (both use “forty”) · 3. forty · 4. forty · 5. Yes, that’s correct.
Related Articles
- ↑ Master Pillar: English Grammar
- ↑ Back to pillar: English Confused Words
Frequently Asked Questions
Is “forty” the only correct spelling?
Yes, absolutely. “Forty” is the sole correct spelling in English. No dictionary recognizes “fourty”. No English-speaking country uses an alternate spelling. If you see “fourty” anywhere, it’s a mistake.
Why does “forty” not have a “u” when “four” and “fourteen” do?
The “-ty” suffix (meaning “tens”) evolved differently from the single-digit words. Historically, the vowel sound in the suffix changed, and the spelling was updated to match. So while “four” keeps the “u”, the compound “forty” dropped it to reflect actual pronunciation.
Is this a British vs. American spelling difference?
No. Both American and British English spell the number as “forty”. There is no regional variant. If you encounter “fourty” in any English text, it’s an error.
Does this affect other “-ty” numbers?
No. Twenty, thirty, fifty, sixty, seventy, eighty, and ninety all have their own patterns (most derived from different roots: two, three, five, six, seven, eight, nine). None of them break the “u” rule in the way “forty” does — because “forty” is the only one where the base word has a “u” but the “-ty” form doesn’t.
What about writing it in compound form (like “forty-two”)?
The same rule applies. It’s “forty-two”, “forty-three”, “forty-nine”, etc. Never “fourty-“.
How important is this spelling in formal writing?
Very important. In formal contexts — cheques, contracts, legal documents, academic papers, job applications — this misspelling signals carelessness. It’s easy to avoid once you know the rule, so there’s no excuse for getting it wrong in final drafts.
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