13th vs. 13rd: Which Spelling Is Correct? Meaning and Examples

You are filling out a form, writing a birthday card, or typing a date into an email. You reach the number 13 and stop. Should it be 13th or 13rd? The number three ends in “rd,” and 13 ends in three, so “13rd” looks logical. It still looks a little off, though, and that feeling is right.

This guide gives you the answer straight away. It then explains why the rule exists, where it came from, and how to apply it to dates, rankings, and bigger numbers like 113th. By the end, you will never second-guess this spelling again.

13rd or 13th: Quick Answer

The correct form is 13th. The form “13rd” is always wrong, in every dialect of English.

Here is the short version:

• Correct: 13th (written out: thirteenth)
• Incorrect: 13rd, 13st, 13nd
• Reason: every number from 11 to 19 takes the “th” ending, even when the last digit is 1, 2, or 3

Use it like this: “Her thirteenth birthday is Friday,” or “He finished 13th in the race.”

What Is the Correct Ordinal Form: 13th or 13rd?

An ordinal number tells you the position of something in an order. First, second, and third are ordinals. So are fourth, fifth, and thirteenth. A cardinal number, by contrast, tells you how many of something there are: one, two, three, thirteen.

When you write an ordinal with digits, you add a short suffix made from the last letters of the spoken word. For example:

• first becomes 1st
• second becomes 2nd
• third becomes 3rd
• fourth becomes 4th

The abbreviation copies the end of the word. That is the key idea. The suffix is not decoration. It is a shortcut for the spelled-out ordinal.

Now look at the word for 13’s position: thirteenth. It ends in “th.” So the abbreviation is 13th. Nothing in the word “thirteenth” ends in “rd,” so “13rd” has no word to abbreviate. Dictionaries such as Collins list the ordinal of thirteen as “thirteenth,” often written 13th, and none of the standard references recognize any other written form.

Why Do People Think “13rd” Is Correct?

The mistake is understandable. It comes from a pattern that works almost everywhere else.

The pattern that fools the eye

Most English ordinals follow a tidy rule based on the final digit:

• Ends in 1: use “st” (1st, 21st, 31st)
• Ends in 2: use “nd” (2nd, 22nd, 32nd)
• Ends in 3: use “rd” (3rd, 23rd, 33rd)
• Everything else: use “th” (4th, 10th, 25th)

Apply that to 13, and you land on “13rd.” The logic feels airtight. The number ends in 3, so it should end in “rd.” Your brain is following a rule that is correct 99 times out of 100 and simply missing the exception.

The cardinal number hides the problem

Another reason is that “thirteen” starts with “thir,” which sounds a lot like “third.” Because 3 and 13 share that sound, people assume they share the ordinal ending too. Many learners of English also memorize the rule by last digit alone, without ever being told that the teens are treated as a separate group.

Auto-pilot typing

After typing 3rd, 23rd, and 33rd several times in a row, the hand keeps going. That is why “13rd” shows up in long lists and schedules.

Why Doesn’t 13 Follow the “Third” Pattern?

Here is the part most guides skip. The number 13 does not actually contain the word “third.”

Look at how each number is built:

• 3 is three, and its ordinal is third
• 13 is thirteen, which is “three” plus “teen,” and its ordinal is thirteenth

The ordinal for 13 is formed by adding “th” to the end of the whole word “thirteen.” It is not formed from “third” at all. The sequence in speech goes twelfth, thirteenth, fourteenth. Nobody says “thirteenrd” or “thirdteen” as an ordinal.

Compare the two:

The difference is the “teen.” Any number whose last two digits fall between 11 and 19 is built with a “teen” ending (or is eleven or twelve, which behave the same way), and these all take “th.” The word for 23, on the other hand, ends in “three,” so its ordinal ends in “third,” and the digits carry “rd.”

So the rule is not random. The suffix follows the final word, not the final digit. Once you see it that way, the exception stops feeling like an exception.

Where Did This Rule Come From?

English ordinals have been irregular for a very long time. The first three are the odd ones out: first, second, and third do not follow the pattern of “number plus th.” From four onward, English settled on adding a “th” sound, as in fourth, fifth, and sixth. The teens followed the same path, which is how we got “thirteenth.”

The writing convention is newer. When people began abbreviating ordinals with digits, they borrowed the last letters of the spoken word. That is why 1st comes from “first,” 2nd from “second,” and 3rd from “third.” Since the spoken word for 13 ends in “th,” its abbreviation does too.

The detailed early history of each ordinal is a specialist topic, and sources describe it with varying certainty. What is not in doubt is the working rule every modern dictionary and style guide follows: the teens, including 13, take “th.”

Historical and Religious Uses of “13th”

The number 13 has carried a lot of cultural weight, and the ordinal form “13th” appears in many famous contexts. Seeing it in real history helps lock the spelling in your memory.

Friday the 13th

The best-known use is Friday the 13th, a date many people in Western cultures consider unlucky. Some sources trace the belief to the idea that thirteen guests sat at the Last Supper, with Judas Iscariot as the thirteenth to take a seat. Other explanations point to older folklore. The origin is debated, but the phrase itself is spelled “the 13th” or “the thirteenth,” never “the 13rd.”

The 13th Amendment

In American history, the Thirteenth Amendment to the Constitution abolished slavery and involuntary servitude, except as punishment for a crime. It was ratified in December 1865. Writers and teachers refer to it as the 13th Amendment all the time, and a well-known 2016 documentary film is titled simply 13th.

Religious and cultural calendars

Different traditions give the number meaning in their own ways. In Shia Islam, the 13th day of the month of Rajab is observed as the birthday of Imam Ali. In Christian tradition, the “thirteenth” at the table in the Last Supper story has shaped superstitions for generations. Some cultures treat 13 as lucky instead.

Time, music, and measurement

• The 13th century covers the years 1201 to 1300.
• In music, a thirteenth chord stacks notes up to the 13th scale degree and is common in jazz.
• Geography uses the 13th parallel north, a circle of latitude.
• Many cities have a 13th Street or Thirteenth Avenue.

In every one of these examples, the spelling is the same. Always “th.”

13rd vs 13th: Quick Comparison Table

Use this table as a fast reference.

And here is how the teens compare with their “neighbors”:

Notice that 21, 22, and 23 follow the normal pattern, while 11, 12, and 13 break it. The teens are the only place where the last digit does not decide the suffix.

Real-Life Examples of “13th” Used Correctly

Seeing the form in context makes it stick. Here are examples across different situations.

Birthdays and milestones

• “Tomorrow is my daughter’s 13th birthday.”
• “They celebrated their 13th anniversary with a trip to the coast.”
• “She turned 13 last month, and her thirteenth birthday party was a surprise.”

Sports and competitions

• “He came in 13th in the marathon.”
• “The team finished in 13th place this season.”
• “That was the 13th goal of the tournament.”

School and work

• “The 13th chapter covers ordinal numbers.”
• “Our office is on the 13th floor.”
• “This is the 13th time she has applied for the grant.”

History and culture

• “The 13th Amendment changed the course of American history.”
• “Many castles in Europe date from the 13th century.”
• “Friday the 13th is a date many people avoid.”

Formal and informal writing

• Formal: “The committee will reconvene on the 13th of March.”
• Casual: “See you on the 13th!”

If you need to spell it out, use “thirteenth.” The digit version and the word version are interchangeable, but the digit version always carries “th.”

Common Mistakes People Make With “13th”

Even people who know the right answer slip up now and then. Here are the most common errors and how to fix them.

1. Writing “13rd” This is the classic one. Fix: the teens always take “th.”

2. Writing “13st” or “13nd” These come from overgeneralizing “first” and “second.” They are wrong for the same reason.

3. Writing “23th” or “33th” This is the opposite mistake. People learn that 13 is “th” and then wrongly apply it to 23, 33, and so on. Fix: only numbers ending in 11, 12, and 13 take “th.” The numbers 23 and 33 take “rd.”

4. Spelling the word “thirteenth” incorrectly Common slips include “thirtenth” (missing the “e”) and “thirteeth.” Remember that the word includes both “teen” and “th,” so the “e” stays.

5. Mixing styles in the same document Pick one style. If you write “5th” and “13th” in one paragraph, do not switch to “fifth” and “thirteenth” in the next unless a style guide tells you to.

13rd or 13th in Dates

Dates cause plenty of confusion, because there are several accepted ways to write them. The 13th works the same way as any other day in all of them.

American style

In the United States, the month usually comes first:

• March 13, 2026
• March 13th, 2026 (common in informal writing)
• 3/13/2026 (numeric)

Many style guides recommend dropping the suffix when the month comes first. Writing “March 13” is clean and standard. Writing “March 13th” is also widely used and not wrong in everyday text.

British and international style

In British English and much of the world, the day comes first:

• 13 March 2026
• 13th March 2026
• The 13th of March, 2026

When the day comes before the month, adding the suffix is common and natural, especially when speaking. You would say “the thirteenth of March.”

Quick date checklist

• Day before month: the suffix is natural (“the 13th of June”)
• Month before day: the suffix is optional (“June 13” or “June 13th”)
• Numeric dates: no suffix at all (13/06/2026)
• Whatever you choose, the suffix, if you use one, is always “th” for the 13th

How to Use 13th for Sequences and Order

Also Read This:Congratulations or Congradulations? Correct Spelling, Meaning and Examples

Ordinals exist to show position. Whenever you are describing where something falls in a list, a race, a series, or a schedule, you use the ordinal form.

Rankings

• “She ranked 13th in the national exam.”
• “It’s the 13th largest city in the region.”

Steps and lists

• “The 13th step in the process is final approval.”
• “Item 13 is the 13th on the list.”

Floors, rows, and places

• “The meeting room is on the 13th floor.”
• “We sat in the 13th row.”

Interestingly, many buildings skip a “13th floor” in their numbering because of superstition. The floor is simply labeled 14, even though it is physically the thirteenth level. If you ever see “13th floor” on a sign, the spelling is still the same.

Repeating events

• “This is the 13th annual charity run.”
• “The company is celebrating its 13th year in business.”

Tips for choosing numerals or words

• Use digits (13th) in lists, tables, addresses, and sports results
• Use words (thirteenth) in formal prose, especially at the start of a sentence
• In dialogue and creative writing, spelling it out reads more smoothly

For example, avoid starting a sentence with a numeral. Instead of “13th place went to Mia,” write “Thirteenth place went to Mia.”

Which One Should You Use: 13th or 13rd?

The answer is simple: always use 13th.

There is no context where “13rd” is acceptable. It is not a regional variation. It is not a casual or slang form. It is not allowed in British English, American English, Australian English, or any other standard variety. Dictionaries do not list it, and teachers, editors, and style guides mark it as an error.

If you are unsure at any point, run through this quick check:

1. Look at the last two digits of the number.
2. If they are 11, 12, or 13, use “th.”
3. If not, look at the last digit and apply the usual rule: 1 is “st,” 2 is “nd,” 3 is “rd,” and everything else is “th.”

That three-step check will get you the right answer every time.

Does This Rule Apply to 113th, 213th, and Other Larger Numbers?

Yes. The teens rule applies to every number that ends in 11, 12, or 13, no matter how large the number gets.

The suffix depends on the last two digits, not on how big the number is. So:

The key line in this table is the last two: 123 ends in 23, which is not in the teens range, so it takes “rd.” Likewise, 1,003 ends in 03, so it also takes “rd.”

This is the same logic programmers use when they write code to attach suffixes to numbers. A typical rule says: if the last two digits are between 11 and 13, use “th”; otherwise, check the last digit. This reflects how English speakers actually say these numbers. Nobody says “one hundred and thirteenrd.”

How to Remember 13th vs 13rd Permanently

Knowing the rule is good. Having a memory trick is better. Here are several you can use, so pick the one that clicks for you.

Trick 1: Say the word out loud

Say “thirteenth.” Hear the “th” sound at the end. You cannot say “thirteenrd” without sounding strange. If the spoken word ends in “th,” so does the written abbreviation.

Trick 2: Remember the “teen” family

Every number from 13 to 19 has “teen” in it, and every one of them takes “th” as an ordinal:

• 13th
• 14th
• 15th
• 16th
• 17th
• 18th
• 19th

Eleven and twelve behave the same way, giving 11th and 12th. If you think of the whole group from 11 to 19 as “the th gang,” you will stop treating 13 as a special case.

Trick 3: Look at the last two digits

Whenever you are unsure, ignore the number’s size and look at the last two digits. If they are 11, 12, or 13, the answer is “th.”

Trick 4: Spell it out first

If you ever freeze, spell the number out in words: thirteenth. The word ends in “th,” so the digits must too. If you can spell the word, you can write the abbreviation.

Final Takeaway

The correct form is 13th, and “13rd” is always a mistake. The teens (11, 12, and 13) are an exception to the usual last-digit rule, so they take “th” just like the spelled-out word “thirteenth.”

The same rule holds for larger numbers such as 113th and 1,013th, while numbers like 23rd and 33rd correctly keep “rd.” When in doubt, say the word out loud or spell it out, and the right ending will be clear.