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
- What Are Ordinal Numbers?
- Difference Between Cardinal and Ordinal Numbers
- The Basic Rules for Writing Ordinal Numbers
- How to Form Ordinal Numbers in Words
- Using Numerals with Ordinal Indicators (1st, 2nd, 3rd, etc.)
- Common Mistakes When Writing Ordinal Numbers
- How to Write Ordinal Numbers in Formal and Informal Contexts
- Writing Ordinal Numbers in Dates
- Ordinal Numbers in Legal, Academic, and Technical Writing
- Ordinal Numbers in Spoken vs. Written English
- Using Ordinal Numbers in Lists, Tables, and Rankings
- Ordinal Numbers in Different English Variants (UK vs. US)
- Style Guide Recommendations (APA, MLA, Chicago, etc.)
- Step-by-Step Process for Writing Ordinal Numbers Correctly
- Examples of Correct and Incorrect Usage
- 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:
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Cardinal: one, two, three
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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:
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The 1st place winner
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The 10th floor
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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 |
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Cardinal: “She has three cats.”
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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:
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Add suffixes to the numeral form to indicate position.
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1 → 1st
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2 → 2nd
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3 → 3rd
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4 → 4th
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After 3rd, most ordinal numbers simply take “th.”
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5 → 5th
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6 → 6th
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7 → 7th
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For numbers ending in 11, 12, and 13, use “th” even though they end in 1, 2, or 3.
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11th, 12th, 13th
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When writing in words, add the appropriate suffix.
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First, Second, Third, Fourth, Fifth, etc.
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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”:
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Four → Fourth
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Six → Sixth
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Ten → Tenth
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Twenty → Twentieth
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Fifty → Fiftieth
When writing compound numbers, only the last word changes:
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Twenty-one → Twenty-first
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Thirty-two → Thirty-second
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Forty-three → Forty-third
Example:
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“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:
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1st (not 1th)
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2nd (not 2th)
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3rd (not 3th)
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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:
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11th hour
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12th grade
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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:
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Using the wrong suffix
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Wrong- 1th, 2th, 3th
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Right-1st, 2nd, 3rd
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Forgetting irregular forms
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Wrong- Twelveth
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Right-Twelfth
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Repeating ordinal indicators
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Wrong- “1st first attempt”
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Right-“First attempt” or “1st attempt”
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Using ordinals instead of cardinals
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Wrong- “I have third apples.”
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Right-“I have three apples.”
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Incorrect compound numbers
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Wrong- “Twenty one-th”
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Right-“Twenty-first”
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Inconsistent formatting
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Don’t mix styles in the same text (e.g., “1st place” and “second place” together).
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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
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Write out ordinal numbers up to “ninth.”
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Example: “The third chapter discusses the theory.”
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Use numerals for 10th and beyond.
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Example: “This is the 12th revision.”
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Informal Writing
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Numerals are acceptable throughout.
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Example: “She came 1st in the race.”
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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:
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“Monday, 5th July 2025”
American English
Ordinals are usually implied, not written:
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“July 5, 2025” (spoken as “July fifth”)
In Text
When mentioning dates within sentences, use ordinal words:
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“The event will take place on the fifth of July.”
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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:
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“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:
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“The third experiment confirmed the hypothesis.”
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“The 15th data set supported the result.”
Technical Writing
Uses numerals for clarity and brevity:
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“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:
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“First,” “Second,” “Third,” “Tenth.”
In writing, these are replaced by ordinal indicators when clarity or brevity is preferred:
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“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
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“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
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Write ordinals in words up to ninth; use numerals beyond that.
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Example: “the fifth experiment,” “the 12th participant.”
MLA Style
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Prefers words for all ordinals below 100 in prose.
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Example: “the twenty-first century.”
Chicago Manual of Style
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Similar to APA; words for one through ninth, numerals for 10th onward.
Associated Press (AP) Style
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Always use numerals with ordinal indicators: “1st,” “2nd,” “10th.”
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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:
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Identify whether you need a cardinal or ordinal number.
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If showing quantity, use cardinal.
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If showing position, use ordinal.
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Decide between word or numeral form.
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Formal prose → words (e.g., “third”).
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Data-heavy writing → numerals (e.g., “3rd”).
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Apply the correct suffix.
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1 → st, 2 → nd, 3 → rd, others → th.
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Exception: 11th, 12th, 13th.
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Check for irregular forms when writing words.
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fifth, ninth, twelfth, etc.
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Maintain consistency throughout your document.
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Review your writing for visual clarity.
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Avoid overusing ordinals where cardinals would suffice.
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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:
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“This is the 5th time she has called.”
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“He won 2nd place in the competition.”
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“The twenty-second floor offers the best view.”
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“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:
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Use visual aids. Numbered charts and sequences make learning intuitive.
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Practice with real-life examples. Dates, floors, and sports rankings are relatable.
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Create memory patterns. Remember the exceptions: first, second, third, fifth, eighth, ninth, twelfth.
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Read aloud. Hearing ordinals reinforces proper pronunciation and rhythm.
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Quiz yourself. Turn ordinal writing into fun exercises, like ranking favorite movies or books.
Frequently Asked Questions
Ordinal numbers are used to show position, order, or rank in a sequence, while cardinal numbers represent quantity. For example, “one, two, three” are cardinal numbers, while “first, second, third” are ordinal numbers. When you say “the 2nd floor” or “the 5th chapter,” you’re using ordinals to indicate order. In contrast, “I have three apples” uses a cardinal number because it expresses how many. Understanding this distinction is essential for accurate communication in English grammar. Ordinals answer “which one?” and cardinals answer “how many?” Ordinal numbers can be written in words (first, second, third) or numerals with suffixes (1st, 2nd, 3rd). Both forms are grammatically correct, but consistency is key. In formal writing, words are preferred up to “ninth,” while numerals are common from “10th” onward. Mastering the difference between ordinal and cardinal numbers helps improve clarity in academic writing, professional communication, and daily English usage.
When learning how to write ordinal numbers correctly, it’s important to understand the suffix system and exceptions. Ordinal numbers are formed by adding the correct ending — st, nd, rd, or th — to the numeral. The basic pattern is:
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1 → 1st (first)
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2 → 2nd (second)
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3 → 3rd (third)
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4 → 4th (fourth)
After the third number, most ordinals take “th,” such as 5th, 6th, 7th, and so on. However, numbers ending in 11, 12, and 13 are exceptions — always use “th” (11th, 12th, 13th) even though they end in 1, 2, or 3.
When writing ordinal numbers in words, remember irregular spellings: first, second, third, fifth, ninth, twelfth. For compound numbers, add the suffix to the last word: twenty-first, thirty-second, forty-third.
In formal English, write out ordinals below 10 and use numerals beyond that (e.g., “the fourth day” but “the 21st century”). These grammar rules ensure your writing remains clear, professional, and consistent across different contexts like dates, rankings, and addresses.
Using ordinal numbers in dates depends on the writing style and regional conventions. In British English, ordinal indicators are often used, such as “5th October 2025.” In American English, ordinals are implied but not written, for example, “October 5, 2025,” though spoken as “October fifth.”
When writing formal letters, reports, or academic papers, consistency is key. Use ordinal numbers in words when part of a sentence:
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Correct: “The meeting is scheduled for the fifth of November.”
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Avoid: “The meeting is on 5th November” in U.S. formal writing.
For legal and official documents, ordinal words are preferred for clarity, e.g., “on the twenty-third day of March, two thousand twenty-five.”
When referring to centuries, editions, or floors, use ordinal numerals:
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“21st century,” “3rd edition,” “5th floor.”
Understanding how to write ordinal numbers in dates ensures grammatical accuracy, especially in business and academic communication. Always follow a single style throughout your document to maintain professional consistency and readability.
Many learners struggle with common errors in ordinal numbers, which can easily be avoided by following grammar rules. The most frequent mistake is using the wrong suffix. For example:
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Wrong- 1th → Right-1st
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Wrong- 2th → Right-2nd
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Wrong- 3th → Right-3rd
Another mistake is forgetting the exceptions for 11, 12, and 13, which always use “th” (11th, 12th, 13th). Writers also often confuse ordinal and cardinal numbers, saying “the three chapter” instead of “the third chapter.” In compound numbers, people incorrectly apply the suffix to both words — avoid “twenty-oneth” and write “twenty-first.” Another issue is mixing styles within the same text, such as writing “1st” in one place and “first” in another. Consistency is essential for professional writing. Avoid doubling words and numbers like “1st first” or “third 3rd.” Use either form, not both. Finally, always check spelling — “twelveth” is incorrect; the right form is “twelfth.” By mastering these details, your English grammar and number writing skills will appear polished and precise.
Deciding whether to write ordinal numbers in words or numerals depends on context, tone, and style guide preferences. In formal or literary writing, such as essays, research papers, and speeches, write out ordinals from first to ninth:
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“First prize,” “Third chapter,” “Ninth row.”
For numbers above nine, use numerals with ordinal suffixes for clarity and simplicity:
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“10th anniversary,” “25th meeting,” “42nd president.”
In academic and professional writing, maintain uniformity — choose either word form or numeral form and stick with it throughout your document. When writing dates, ordinal numerals (1st, 2nd, 3rd) are acceptable in British English but usually omitted in American formatting. For legal, technical, and business writing, numerals are preferred for accuracy and brevity, especially in lists, data tables, and contracts. Meanwhile, creative or descriptive writing benefits from the word form for smoother readability. Consistency is key — once you establish your format, follow it throughout the text. Knowing when to use words or numerals helps ensure your ordinal numbers are grammatically correct, visually clear, and stylistically appropriate for every situation.