Ordinal Numbers | Meaning & Examples
Ordinal numbers—such as “second” and “95th”—provide helpful details about sequences and rankings. You can write ordinal numbers as words or numerals combined with “-st,” “-nd,” “-rd,” or “-th” (e.g., “17th”). Some style guidelines recommend words for “first” through “ninth” and numerals for “10th” and higher.
In a sentence, an ordinal number can play these roles:
- A determiner that shows the position of a noun in a numbered sequence (“the fifth season of Stranger Things” or “the 90th percentile”)
- An adverb that modifies a verb to show the order of events (e.g., “eat first and then watch TV”)
- An adverb that modifies an adjective to show a noun’s ranking (e.g., “the second tallest building”)
When an ordinal number is a determiner, it goes after another determiner (e.g., the definite article “the” or the possessive adjective “your”).
First write your outline, and then start the first draft.
The third longest river in the world is the Yangtze River.
Ordinal number meaning
An ordinal number shows the position of a noun, verb, or adjective in a sequence or system of levels or rankings. The following table illustrates some of the most common uses of ordinal numbers.
| Ordinal number use | Ordinal number in a sentence |
|---|---|
| Competition results | Philip Kim won first place in men’s breakdancing. |
| School levels | Krista teaches 10th grade English. |
| Street names | Many celebrities have lived on Fifth Avenue. |
| The doctor’s office is on 63rd Street. | |
| Steps in a process (e.g., a recipe) | First mix the butter and sugar, and then add vanilla. |
| The first step is to sauté the mushrooms, and the second step is to grate the parmesan. | |
| Centuries | The bicycle was invented during the 19th century. |
| Dates with “the” and “of” | Do you remember the 21st night of September? |
| Birthdays and anniversaries | We had the best time at Bert’s 60th birthday party! |
| Location in a line or series of rows | We were the third people in line to buy tickets, and we got 10th row seats. |
| Relationship to a superlative adjective) | Canada is the second largest country. |
Ordinal vs cardinal numbers
Cardinal numbers and ordinal numbers have different uses and spellings.
- Use cardinal numbers (e.g., “two” and “15”) to count or show quantity (e.g., “15 steps”)
- Use ordinal numbers to show ranking or sequence (e.g., “the 15th floor”).
- Both can be words or numerals, but ordinal numbers end with the suffixes “-st,” “-nd,” “-rd,” or “-th” (e.g., “28th anniversary” or “fifth place”).
Cardinal numbers can also show a ranking or level but only when they go after the noun, which is usually capitalized (e.g., “Chapter 2” is a correct alternative for “the second chapter”).
| Cardinal numbers | Ordinal numbers |
|---|---|
| We’re going to rewatch Episode 1 before we watch Episode 2. | During the second episode, David and Alexis attend a party. |
| The hotel has 45 floors and over 700 rooms. | The 45th floor has an award-winning restaurant. |
- The equinox is on March 20th, 2025.
- The equinox is on March 20, 2025.
- The equinox is on the 20th of March this year.
When you’re writing sentences with dates or other numbers, QuillBot’s free Grammar Checker can help you avoid errors.
When to spell out ordinal numbers
There are two ways to write ordinal numbers:
- You can spell them out as words that end in “-st,” “-nd,” “-rd,” or “-th” (e.g., “twenty-eighth anniversary”).
- You can write a cardinal number combined with “-st,” “-nd,” “-rd,” or “-th” (e.g., “the 17th of March”).
| Ordinal numbers | Ordinal words | |
|---|---|---|
| 1st–9th | 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th | First, second, third, fourth, fifth, sixth, seventh, eight, and ninth |
| 10th–19th | Cardinal number + “-th” (e.g., 18th) | Cardinal number word + “-th” (e.g., eighteenth) |
| Multiples of 10 | Cardinal number + “-th” (e.g., 40th) | Cardinal number word (e.g., forty) without the “-y” + “-ieth” (e.g., fortieth) |
| 21st–99th (except multiples of 10) | Cardinal number + the ending that matches the 2nd number (e.g., 41st, 72nd, 53rd, 84th). | A cardinal number word for the first digit (e.g., twenty) + an ordinal number word between first and ninth (e.g., fifty-third) |
Each instructor, workplace, or style book usually has guidelines about when to spell out ordinal numbers. Most guidelines say to spell out “first” through “ninth” and use numerals for “10th” and higher (e.g., “the 12th song on the album”).
Your style guidelines will also indicate whether to use a hyphen in ordinal number words (e.g., “forty-second floor”) or to avoid words for double-digit ordinals and use numerals instead (e.g., “42nd”).
When you’re unsure about how to format ordinal numbers, check with your instructor, workplace guidelines, or style book.
In academic writing, the rules about when to spell out ordinal numbers depend on whether you’re using APA, MLA, or Chicago style.
| Style guide | Ordinal number rules | Examples |
|---|---|---|
| APA | Words for “first” through “ninth” | The first case study
Our second attempt The fourth-grade reading curriculum |
| Numerals for all ordinals “10th” and higher | 11th grade
The 15th question on the survey |
|
| Numerals for time, dates, and percentiles | 4th year
5th percentile |
|
| MLA | Words for ordinals that are one or two words (even percentiles) | Fiftieth percentile
Twenty first century |
| Numerals for ordinals that are more than two words | 101st annual awards ceremony
150th location |
|
| Chicago | Words for “first” through “100th” with a hyphen between two words | Twenty-first century
Thirteenth line of the poem |
| Numerals for “101st” and higher | 150th running of the Kentucky Derby
102nd floor of the skyscraper |
Frequently asked questions about ordinal numbers
- How do you define ordinal number?
-
An ordinal number is defined as a number that identifies a position in a sequence or system of levels or rankings.
You can write ordinal numbers as words (e.g., “third”) or cardinal numbers combined with “-st,” “-nd,” “-rd,” or “-th” (e.g., “20th”).
For example, someone might live on the 31st floor of a building or win fourth place in a competition.
When you’re writing with ordinal numbers, QuillBot’s free Grammar Checker can help you avoid errors.
- Do you spell out numbers under 10?
-
In most cases, spell out numbers under 10, which include cardinal numbers (e.g., “four books” and “nine teachers”) and ordinal numbers (e.g., fifth grade). However, there are exceptions and variations, depending on the style guidelines you’re using.
For example, APA, MLA, and Chicago guidelines require numerals for numbers under 10 when they’re part of dates, times, and measurements (e.g., “The veterinarian fed the kittens a high calorie diet until they weighed 2 pounds”).
You can also use numerals for one through nine when they go after nouns and are part of a series (e.g., “Chapter 7 takes place in a cave”).
Always check with your style book, instructor, or workplace guidelines when you’re unsure about how to spell out cardinal numbers or ordinal numbers.
QuillBot’s free Grammar Checker can also help you use numbers correctly in your writing.
- Do you hyphenate numbers?
-
Most (but not all) style books say to hyphenate numbers that have two words (e.g., “forty-six days”).
Unless your style requirements say otherwise, use a hyphen (-) when you need to write the words for a double-digit cardinal number (e.g., “thirty-one flavors”) or ordinal number (e.g., “twenty-first birthday”).
Some of the most common guidelines for hyphens and numbers are as follows:
- APA uses hyphens for two-word numbers but only uses words for 10 and greater at the beginning of a sentence (e.g., “Last year, 25 teachers retired” or “Twenty-five teachers retired last year”).
- Chicago uses words for numbers up to 100 and hyphens in numbers with two words (e.g., “The conference included workshops by twenty-seven professional musicians”).
- MLA requires words for all numbers that have one or two words and doesn’t use hyphens for numbers (e.g., “The researchers interviewed thirty two students”).
QuillBot’s free Grammar Checker can help you with hyphens, cardinal numbers, and more.
- When do you spell out numbers in APA?
-
The guidelines to spell out numbers in APA style writing are as follows:
- Spell out the ordinal numbers “first” through “ninth” and the cardinal numbers “one” through “nine” unless they express time, measurements, or percentages/percentiles (e.g., “We interviewed 30 fifth-grade students from three schools”).
- Use numerals for numbers 10 and greater or 10th and higher (e.g., “The 11th-grade students took a survey”).
- Numbers that begin sentences should also be spelled out even if they are greater than 10 (e.g., “Twelve of the participants said they prefer reading nonfiction”).
- When possible, avoid beginning sentences with double-digit numbers. Instead, reword the sentence so that you can use numerals (e.g., “The results showed that 15 students prefer graphic novels”).
When you’re working on APA style essays, QuillBot’s free Grammar Checker can help you write numbers correctly.
