How To Write Ordinal Numbers Correctly

Ordinal numbers are everywhere — in dates, rankings, addresses, reports, and even storytelling. Whether you’re writing “the 21st century,” “the 3rd chapter,” or “the 5th attempt,” knowing how to write ordinal numbers correctly ensures your writing is both accurate and professional. Many writers underestimate how essential this simple rule of grammar is. A small mistake, such as writing “1th” instead of “1st”, can instantly disrupt readability and credibility. In academic, business, or formal communication, precision matters — and ordinal numbers are no exception. This guide provides everything you need to master the correct way to write ordinal numbers — in both words and figures — with clear rules, examples, and style guidance.

Table of Contents

1. What Are Ordinal Numbers?
2. Difference Between Cardinal and Ordinal Numbers
3. The Basic Rules for Writing Ordinal Numbers
4. How to Form Ordinal Numbers in Words
5. Using Numerals with Ordinal Indicators (1st, 2nd, 3rd, etc.)
6. Common Mistakes When Writing Ordinal Numbers
7. How to Write Ordinal Numbers in Formal and Informal Contexts
8. Writing Ordinal Numbers in Dates
9. Ordinal Numbers in Legal, Academic, and Technical Writing
10. Ordinal Numbers in Spoken vs. Written English
11. Using Ordinal Numbers in Lists, Tables, and Rankings
12. Ordinal Numbers in Different English Variants (UK vs. US)
13. Style Guide Recommendations (APA, MLA, Chicago, etc.)
14. Step-by-Step Process for Writing Ordinal Numbers Correctly
15. Examples of Correct and Incorrect Usage
16. Tips for Teaching or Learning Ordinal Numbers

What Are Ordinal Numbers?

Ordinal numbers show position or order in a sequence. Unlike cardinal numbers, which tell how many, ordinal numbers tell which one.

For example:

• Cardinal: one, two, three

• Ordinal: first, second, third

If you say “I finished second in the race,” the word second shows your position, not the quantity.

Ordinal numbers are often used when ranking, ordering, or describing sequence, such as:

• The 1st place winner

• The 10th floor

• The 5th day of the week

Difference Between Cardinal and Ordinal Numbers

Understanding the distinction between cardinal and ordinal numbers is key to using them correctly.

Type	Function	Examples
Cardinal Numbers	Show quantity	one, two, three, four
Ordinal Numbers	Show position or order	first, second, third, fourth

• Cardinal: “She has three cats.”

• Ordinal: “Her third cat is the most playful.”

In writing, confusing the two can change meaning entirely. Saying “the third day” is different from “three days.”

The Basic Rules for Writing Ordinal Numbers

Writing ordinal numbers follows a few clear grammatical rules:

1. Add suffixes to the numeral form to indicate position.

   • 1 → 1st

   • 2 → 2nd

   • 3 → 3rd

   • 4 → 4th

2. After 3rd, most ordinal numbers simply take “th.”

   • 5 → 5th

   • 6 → 6th

   • 7 → 7th

3. For numbers ending in 11, 12, and 13, use “th” even though they end in 1, 2, or 3.

   • 11th, 12th, 13th

4. When writing in words, add the appropriate suffix.

   • First, Second, Third, Fourth, Fifth, etc.

5. Avoid mixing forms. Don’t write “1st first” or “second 2nd.” Use either words or numerals, not both.

How to Form Ordinal Numbers in Words

Forming ordinal numbers in words is straightforward, but a few irregular forms must be memorized.

Irregular Ordinals

Cardinal	Ordinal
One	First
Two	Second
Three	Third
Five	Fifth
Eight	Eighth
Nine	Ninth
Twelve	Twelfth

These words deviate from the standard “add -th” pattern.

Regular Ordinals

For most numbers beyond twelve, simply add “th”:

• Four → Fourth

• Six → Sixth

• Ten → Tenth

• Twenty → Twentieth

• Fifty → Fiftieth

When writing compound numbers, only the last word changes:

• Twenty-one → Twenty-first

• Thirty-two → Thirty-second

• Forty-three → Forty-third

Example:

• “He finished in the twenty-third position.”

Using Numerals with Ordinal Indicators (1st, 2nd, 3rd, etc.)

In digital and print writing, numerals with indicators are widely used. Here’s how to do it correctly:

Correct Forms:

• 1st (not 1th)

• 2nd (not 2th)

• 3rd (not 3th)

• 4th, 5th, 6th, and so on

Special Rules for 11, 12, 13

Even though 11 ends with “1,” you still write “11th,” not “11st.”

Examples:

• 11th hour

• 12th grade

• 13th birthday

These three exceptions break the usual pattern.

Formatting Tips

When writing professionally, avoid using superscript (“1ˢᵗ”) unless required by style. Standard form — “1st” — is universally acceptable in digital and print media.

Common Mistakes When Writing Ordinal Numbers

Even fluent English writers make errors with ordinal numbers. Let’s identify the most frequent ones:

1. Using the wrong suffix

   • Wrong- 1th, 2th, 3th

   • Right-1st, 2nd, 3rd

2. Forgetting irregular forms

   • Wrong- Twelveth

   • Right-Twelfth

3. Repeating ordinal indicators

   • Wrong- “1st first attempt”

   • Right-“First attempt” or “1st attempt”

4. Using ordinals instead of cardinals

   • Wrong- “I have third apples.”

   • Right-“I have three apples.”

5. Incorrect compound numbers

   • Wrong- “Twenty one-th”

   • Right-“Twenty-first”

6. Inconsistent formatting

   • Don’t mix styles in the same text (e.g., “1st place” and “second place” together).

How to Write Ordinal Numbers in Formal and Informal Contexts

The choice between writing ordinal numbers in words or numerals depends on the level of formality.

Formal Writing

• Write out ordinal numbers up to “ninth.”

  • Example: “The third chapter discusses the theory.”

• Use numerals for 10th and beyond.

  • Example: “This is the 12th revision.”

Informal Writing

• Numerals are acceptable throughout.

  • Example: “She came 1st in the race.”

Consistency is the key rule — choose one style and maintain it throughout your document.

Writing Ordinal Numbers in Dates

Ordinal numbers appear frequently in dates, but their formatting depends on regional and stylistic preferences.

British English

Ordinals are often written out in dates:

• “Monday, 5th July 2025”

American English

Ordinals are usually implied, not written:

• “July 5, 2025” (spoken as “July fifth”)

In Text

When mentioning dates within sentences, use ordinal words:

• “The event will take place on the fifth of July.”

• Avoid “on 5th July” in formal US English.

Ordinal Numbers in Legal, Academic, and Technical Writing

Each writing domain has its conventions for ordinal numbers.

Legal Documents

Clarity is vital, so ordinal words are often written out completely:

• “On the twenty-fourth day of September, two thousand twenty-five.”

Academic Writing

Follows formal guidelines — typically write ordinals up to ninth in words and use numerals after that:

• “The third experiment confirmed the hypothesis.”

• “The 15th data set supported the result.”

Technical Writing

Uses numerals for clarity and brevity:

• “Install the 3rd component after the 2nd.”

Ordinal Numbers in Spoken vs. Written English

In speech, ordinal numbers are almost always pronounced with their full suffixes:

• “First,” “Second,” “Third,” “Tenth.”

In writing, these are replaced by ordinal indicators when clarity or brevity is preferred:

• “1st,” “2nd,” “3rd,” “10th.”

However, never mix the spoken and written forms directly (e.g., writing “third 3rd”).

Using Ordinal Numbers in Lists, Tables, and Rankings

Ordinal numbers organize data efficiently in structured content.

In Lists

• “1st, 2nd, 3rd place” is acceptable for compact formats like results or tables.

In Tables

Use numerals for clarity:

Rank	Name	Score
1st	Emma	98
2nd	Liam	95
3rd	Ava	92

In Rankings

Avoid ambiguity by using the correct suffix. “4rd” or “2th” are obvious typos that hurt credibility.

Ordinal Numbers in Different English Variants (UK vs. US)

Though the rules are similar, subtle stylistic differences exist.

Context	US English	UK English
Dates	July 5, 2025	5th July 2025
Writing Style	More numerals	More written words
Formal Preference	1st, 2nd, 3rd	first, second, third

In both styles, however, suffix conventions remain identical.

Style Guide Recommendations (APA, MLA, Chicago, etc.)

Professional writing often follows style guides that standardize number formatting.

APA Style

• Write ordinals in words up to ninth; use numerals beyond that.

• Example: “the fifth experiment,” “the 12th participant.”

MLA Style

• Prefers words for all ordinals below 100 in prose.

• Example: “the twenty-first century.”

Chicago Manual of Style

• Similar to APA; words for one through ninth, numerals for 10th onward.

Associated Press (AP) Style

• Always use numerals with ordinal indicators: “1st,” “2nd,” “10th.”

• Common in journalism and newswriting.

Step-by-Step Process for Writing Ordinal Numbers Correctly

Here’s a structured method for writing ordinals the right way every time:

1. Identify whether you need a cardinal or ordinal number.

   • If showing quantity, use cardinal.

   • If showing position, use ordinal.

2. Decide between word or numeral form.

   • Formal prose → words (e.g., “third”).

   • Data-heavy writing → numerals (e.g., “3rd”).

3. Apply the correct suffix.

   • 1 → st, 2 → nd, 3 → rd, others → th.

   • Exception: 11th, 12th, 13th.

4. Check for irregular forms when writing words.

   • fifth, ninth, twelfth, etc.

5. Maintain consistency throughout your document.

6. Review your writing for visual clarity.

   • Avoid overusing ordinals where cardinals would suffice.

Examples of Correct and Incorrect Usage

Incorrect	Correct
1th place	1st place
2th round	2nd round
3th chapter	3rd chapter
Twelveth	Twelfth
Forty-one-th	Forty-first
11st edition	11th edition

Proper examples in sentences:

• “This is the 5th time she has called.”

• “He won 2nd place in the competition.”

• “The twenty-second floor offers the best view.”

• “Our company celebrates its 10th anniversary today.”

Tips for Teaching or Learning Ordinal Numbers

Mastering ordinal numbers is especially helpful for English learners. Here are some effective techniques:

1. Use visual aids. Numbered charts and sequences make learning intuitive.

2. Practice with real-life examples. Dates, floors, and sports rankings are relatable.

3. Create memory patterns. Remember the exceptions: first, second, third, fifth, eighth, ninth, twelfth.

4. Read aloud. Hearing ordinals reinforces proper pronunciation and rhythm.

5. Quiz yourself. Turn ordinal writing into fun exercises, like ranking favorite movies or books.