Have you ever written 13rd instead of 13th? You’re not alone! Ordinal numbers in English can be confusing because some end in -st, -nd, or -rd, while others end in -th. However, for the number 13, only one ending is correct.
In this guide, you’ll learn the difference between 13rd vs 13th, the rules for ordinal numbers, examples, common mistakes, and an easy memory trick to help you remember the correct form.
Quick Answer
- 13th ✅ — Correct ordinal form.
- 13rd ❌ — Incorrect ordinal form.
Use 13th whenever you’re referring to the thirteenth position, date, floor, chapter, or event.
Examples:
- Her birthday is on the 13th of May.
- He finished in 13th place.
What Do 13rd and 13th Mean?
Although these forms look similar, only one follows standard English grammar.
What Is 13th?
13th is the correct ordinal form of the number 13.
It is used to indicate:
- Position in a sequence.
- Dates.
- Rankings.
- Floors.
- Chapters.
- Anniversaries.
Examples:
- Today is the 13th of October.
- She came in 13th place.
- We live on the 13th floor.
- Read the 13th chapter first.
What Is 13rd?
13rd is an incorrect ordinal form.
It is not recognized in standard English and should never be used in writing.
The confusion happens because people associate the digit 3 with the suffix -rd, but ordinal suffixes depend on the entire number, not just the last digit.
13rd vs 13th Comparison Table
| Feature | 13rd | 13th |
|---|---|---|
| Correct English Form | ❌ No | ✅ Yes |
| Grammar Rule | Incorrect | Correct |
| Used in Dates | No | Yes |
| Used in Rankings | No | Yes |
| Used in Everyday English | No | Very Common |
Why Is “13th” Correct?
English ordinal numbers follow these rules:
- 1st → First
- 2nd → Second
- 3rd → Third
- 4th–20th → Use -th
The numbers 11, 12, and 13 are special exceptions.
Even though 13 ends in 3, it still takes -th because it belongs to the group 11–13, which always uses -th.
Therefore:
- 13th ✅ — Correct.
- 13rd ❌ — Incorrect.
Examples of 13th in Sentences
- My appointment is on the 13th.
- She celebrated her 13th birthday.
- He finished 13th in the race.
- The meeting starts on the 13th of June.
- They moved into the 13th apartment.
- Today marks the 13th anniversary.
- Open the 13th page of the book.
Common Mistakes People Make
Many writers accidentally:
- Write 13rd because the number ends in 3.
- Forget that 11, 12, and 13 are exceptions.
- Use the wrong ordinal suffix in dates.
- Miss the typo while proofreading.
Incorrect:
- ❌ Today is the 13rd of August.
Correct:
- ✅ Today is the 13th of August.
Simple Memory Trick
💡 Memory Trick
Special Rule Box
- 11th
- 12th
- 13th
These three numbers are a special group and always end with -th, even though 13 ends with the digit 3.
Rule: Remember 11–13 always use -th.
When Should You Use 13th?
Use 13th when talking about:
- Dates.
- Birthdays.
- Rankings.
- Floors.
- Chapters.
- Anniversaries.
Examples:
- 13th birthday.
- 13th floor.
- 13th chapter.
- 13th place.
- 13th day.
- 13th anniversary.
When Should You Use 13rd?
Never.
13rd is always incorrect and should be replaced with 13th.
American vs British English
There is no difference between American and British English.
Both varieties use:
- ✅ 13th
- ❌ 13rd
The ordinal form is identical in both.
Related Words and LSI Keywords
- 13th meaning
- ordinal numbers
- English grammar
- ordinal suffixes
- first second third
- thirteenth
- dates in English
- grammar rules
- English writing
- commonly confused numbers
- proofreading tips
- language learning
- correct English usage
- number spelling
Tips for Remembering the Difference
- 13th is always correct.
- Remember that 11, 12, and 13 all use -th.
- Don’t choose the suffix based only on the last digit.
- Check dates carefully before publishing.
- Use spell check when writing.
Frequently Asked Questions
Is 13rd correct?
No. 13rd is grammatically incorrect.
Which is correct: 13rd or 13th?
13th is the correct ordinal form.
Why isn’t 13 written as 13rd?
Because 11, 12, and 13 are special exceptions that always take the suffix -th.
Is 13th used in American and British English?
Yes. Both varieties use 13th.
Can I write 13rd in formal writing?
No. Always use 13th.
What are the correct endings for ordinal numbers?
- 1st
- 2nd
- 3rd
- 4th–20th (including 11th, 12th, and 13th)
Summary
The difference between 13rd vs 13th is simple. 13th is the correct ordinal form used for dates, rankings, birthdays, and positions. 13rd is a common grammar mistake because many people focus only on the last digit instead of the complete number.
Whenever you’re writing about the number thirteen in an ordinal form, always use 13th.
