Ordinal numbers are used to show the position, order, or rank of something in a sequence. We use them every day when talking about dates, rankings, floors, anniversaries, and steps in a process. Common examples include first (1st), second (2nd), third (3rd), and fourth (4th).
Learning how to write ordinal numbers correctly can sometimes be confusing because different numbers take different endings, such as -st, -nd, -rd, and -th. There are also important exceptions, including 11th, 12th, and 13th.
In this guide, you will learn how to write ordinal numbers correctly in words and numerical form, understand the main suffix rules and exceptions, and see practical examples of ordinal numbers used in English sentences.
Table of Contents
What Are Ordinal Numbers in English?
Ordinal numbers are numbers that show the position, order, or rank of a person or thing in a sequence. They answer questions such as “Which one?” or “What position?”
For example:
- First (1st) – position number one
- Second (2nd) – position number two
- Third (3rd) – position number three
- Fourth (4th) – position number four
- Fifth (5th) – position number five
Consider this example:
- Sara finished first in the race.
The word first tells us Sara’s position in the race. It does not tell us how many people participated.
Ordinal numbers are commonly used for dates, rankings, floors, anniversaries, competitions, and the order of steps or events.
They are different from cardinal numbers, which tell us how many people, objects, or things there are. For example, three is a cardinal number, while third is an ordinal number.
Examples of Ordinal Numbers:
- First
- Second
- Third
Examples of Cardinal Numbers:
- One
- Two
- Three
Ordinal numbers are used in various situations, such as dates, rankings, and steps in a process. Therefore, it is essential to know how to write these numbers correctly so that your writing is clear and understandable to your readers.
Difference Between Ordinal and Cardinal Numbers
Cardinal and ordinal numbers have different purposes in English. Cardinal numbers tell us how many, while ordinal numbers tell us the position or order of something.
| Cardinal Number | Ordinal Number |
|---|---|
| one (1) | first (1st) |
| two (2) | second (2nd) |
| three (3) | third (3rd) |
| four (4) | fourth (4th) |
| five (5) | fifth (5th) |
| ten (10) | tenth (10th) |
| twenty-one (21) | twenty-first (21st) |
Consider these examples:
- I have three books. — Three is a cardinal number because it tells us how many books there are.
- I am reading the third book. — Third is an ordinal number because it identifies the book’s position in a sequence.
Another example:
- Five runners participated in the race. — Five tells us the number of runners.
- Maria finished fifth in the race. — Fifth tells us Maria’s position.
A simple way to remember the difference is:
Cardinal numbers = quantity: one, two, three, four
Ordinal numbers = position or order: first, second, third, fourth
How to Write Ordinal Numbers
Ordinal numbers can be written either in words or as numerals with ordinal suffixes. For example, you can write first or 1st, second or 2nd, and third or 3rd.
Writing Ordinal Numbers in Words
Some common ordinal numbers written in words are:
-
1st — first
-
2nd — second
-
3rd — third
-
4th — fourth
-
5th — fifth
-
6th — sixth
-
7th — seventh
-
8th — eighth
-
9th — ninth
-
10th — tenth
-
11th — eleventh
-
12th — twelfth
-
13th — thirteenth
-
20th — twentieth
-
21st — twenty-first
-
22nd — twenty-second
-
23rd — twenty-third
When ordinal numbers are written as words, they are normally lowercase unless they appear at the beginning of a sentence or capitalization is otherwise required.
For example:
-
She finished first in the competition.
-
This is my second visit to London.
-
First, read the instructions carefully.
Notice that some ordinal words have irregular spellings. For example, one becomes first, two becomes second, three becomes third, five becomes fifth, eight becomes eighth, nine becomes ninth, and twelve becomes twelfth.
Writing Ordinal Numbers in Numerical Form
To write an ordinal number in numerical form, add the appropriate suffix directly after the number:
-
1 → 1st
-
2 → 2nd
-
3 → 3rd
-
4 → 4th
-
10 → 10th
-
21 → 21st
-
32 → 32nd
-
43 → 43rd
-
54 → 54th
Do not put an apostrophe between the number and its suffix.
-
1’st ❌
-
2’nd ❌
-
1st ✓
-
2nd ✓
Ordinal Number Suffix Rules
There are four ordinal suffixes in English: -st, -nd, -rd, and -th.
1. Use -st for most numbers ending in 1.
Examples:
-
1st
-
21st
-
31st
-
101st
2. Use -nd for most numbers ending in 2.
Examples:
-
2nd
-
22nd
-
32nd
-
102nd
3. Use -rd for most numbers ending in 3.
Examples:
-
3rd
-
23rd
-
33rd
-
103rd
4. Use -th for most other numbers.
Examples:
-
4th
-
5th
-
6th
-
10th
-
24th
-
50th
-
100th
The Important 11th, 12th, and 13th Exception
Numbers ending in 11, 12, or 13 use -th, not -st, -nd, or -rd.
Therefore:
-
11th ✓ — not 11st
-
12th ✓ — not 12nd
-
13th ✓ — not 13rd
-
111th ✓ — not 111st
-
112th ✓ — not 112nd
-
113th ✓ — not 113rd
After these exceptions, the normal pattern continues:
-
121st
-
122nd
-
123rd
-
124th
A simple rule to remember is to check the last two digits first. If they are 11, 12, or 13, use -th. Otherwise, look at the final digit to determine whether to use -st, -nd, -rd, or -th.
When to Use Ordinal Numbers
Ordinal numbers are used whenever we need to show position, order, rank, or sequence. Here are some of the most common situations in which they appear.
1. Dates
Ordinal numbers are commonly used when dates are spoken and in some written date formats.
Examples:
-
Her birthday is on the 5th of May.
-
We will meet on June 15th.
-
The celebration takes place on the 4th of July.
In American English, dates are often written without the ordinal suffix, such as June 15, even though we normally say “June fifteenth.”
2. Rankings and Positions
Ordinal numbers indicate someone’s or something’s position in a competition, list, or ranking.
Examples:
-
She finished first in the race.
-
Our team came in second.
-
He won 3rd place in the competition.
-
The school ranked 10th in the state.
3. Floors of Buildings
Ordinal numbers are commonly used to identify floors.
Examples:
-
Our office is on the third floor.
-
She lives on the 10th floor.
-
The restaurant is on the 21st floor.
4. Anniversaries and Birthdays
Ordinal numbers can show how many years have passed since an event.
Examples:
-
They celebrated their 25th wedding anniversary.
-
The company is celebrating its 50th anniversary.
-
We celebrated his 18th birthday.
5. Steps and Sequence
Ordinal numbers can show the order of steps, instructions, events, or ideas.
Examples:
-
First, wash your hands.
-
Second, prepare the ingredients.
-
Third, mix everything together.
They can also refer to a particular item in a sequence:
-
Read the second chapter before class.
-
The third step is the most important.
-
This is the fourth question on the test.
6. Centuries
Ordinal numbers are used when referring to centuries.
Examples:
-
Shakespeare lived during the 16th century.
-
The Industrial Revolution began in the 18th century.
-
We live in the 21st century.
7. Fractions
Many fractions use ordinal-number forms for the denominator.
Examples:
-
one-third (1/3)
-
one-fourth (1/4)
-
three-fifths (3/5)
However, half is used for 1/2 rather than second.
As these examples show, ordinal numbers appear frequently in everyday English whenever the order or position of something matters.
How to Use Ordinal Numbers Correctly
Knowing the basic suffix rules is important, but you should also avoid several common mistakes when writing ordinal numbers.
1. Use the Correct Ordinal Suffix
Make sure you use -st, -nd, -rd, or -th correctly.
Incorrect:
-
1th
-
2th
-
3th
-
21th
Correct:
-
1st
-
2nd
-
3rd
-
21st
Remember that 11th, 12th, and 13th are exceptions and always take -th.
2. Do Not Confuse the Number 1 with the Letter I
The ordinal form of 1 is 1st, with the number 1, not the capital letter I.
Incorrect:
-
Ist
-
June Ist
Correct:
-
1st
-
June 1st
When written in words, 1st becomes first.
3. Do Not Add an Apostrophe Before the Suffix
Ordinal suffixes are attached directly to the numeral.
Incorrect:
-
1’st
-
2’nd
-
3’rd
Correct:
-
1st
-
2nd
-
3rd
4. Watch the 11, 12, and 13 Exceptions
Do not choose a suffix based only on the final digit when the number ends in 11, 12, or 13.
Incorrect:
-
11st
-
12nd
-
13rd
-
111st
Correct:
-
11th
-
12th
-
13th
-
111th
The same rule applies to larger numbers ending in 11, 12, or 13.
5. Use Ordinal Numbers When Position Matters
Use an ordinal number when you are describing order, rank, or position, rather than quantity.
Compare:
-
Three students finished the test. — Three tells us how many students.
-
She was the third student to finish the test. — Third tells us her position.
Similarly:
-
He has five books. — quantity
-
He is reading the fifth book. — position
6. Include an Article or Determiner When Needed
Ordinal numbers used before nouns are often preceded by the, a possessive word, or another determiner.
Examples:
-
She won the first prize.
-
This is my second attempt.
-
We visited the third museum on our list.
-
It was their 25th anniversary.
However, the is not required in every construction:
-
She finished first.
-
He came second in the race.
Using the correct suffix and choosing an ordinal number only when you are describing position, order, or sequence will make your writing clearer and more accurate.
Tips for Writing Ordinal Numbers Clearly
Following a few simple guidelines can make ordinal numbers easier to read and keep your writing consistent.
1. Be Consistent
Try to use a consistent style for ordinal numbers throughout the same piece of writing.
For example, avoid unnecessarily switching between forms such as:
-
first, 2nd, third, 4th
A more consistent version would be:
-
first, second, third, fourth
or, when numerals are appropriate:
-
1st, 2nd, 3rd, 4th
The best choice depends on the type of writing and any style guide you are following.
2. Consider the Context
In general prose, smaller ordinal numbers are often written as words because they are easy to read.
Examples:
-
This is my first visit.
-
She made a second attempt.
-
He finished in third place.
Numerals can be useful when the number is large, when space is limited, or when numerical information needs to be easy to scan.
Examples:
-
the 25th anniversary
-
the 101st participant
-
the 21st century
3. Follow the Required Style Guide
Different publications, schools, businesses, and academic fields may follow different conventions for writing numbers.
If you are writing an academic paper, business document, or publication, check the required style guide and follow its rules consistently.
4. Use the Correct Spelling When Writing Ordinals in Words
Some ordinal numbers do not follow a simple spelling pattern.
Pay particular attention to forms such as:
-
five → fifth
-
eight → eighth
-
nine → ninth
-
twelve → twelfth
-
twenty → twentieth
-
thirty → thirtieth
These spellings are common sources of mistakes for English learners.
5. Use Hyphens in Compound Ordinal Numbers
Compound ordinal numbers from twenty-one to ninety-nine are normally hyphenated when written in words.
Examples:
-
21st → twenty-first
-
32nd → thirty-second
-
43rd → forty-third
-
99th → ninety-ninth
Notice that only the final part of the compound number changes to an ordinal form.
For example:
-
twenty-one → twenty-first
-
thirty-two → thirty-second
-
forty-three → forty-third
6. Check Titles and Headings Carefully
When an ordinal number appears in a title or heading, follow the capitalization style used for the rest of the title.
Examples:
-
The 5th Annual Science Fair
-
My First Day at College
-
The 21st Century and Technology
Using a consistent format, correct spelling, and the appropriate style for your context will make ordinal numbers clearer and easier for readers to understand.
Examples of Ordinal Numbers in Sentences
Here are examples of ordinal numbers used correctly in different situations.
Position and Order
-
Emma finished first in the race.
-
James came second in the competition.
-
Our team finished in third place.
-
She was the fourth person to arrive.
-
This is my second attempt at the test.
Dates
-
Her birthday is on the 5th of May.
-
Our appointment is on September 21st.
-
They got married on the 3rd of June.
-
The event will take place on October 12th.
Floors and Locations
-
My apartment is on the second floor.
-
His office is on the 10th floor.
-
The restaurant is located on the 21st floor.
Steps and Sequences
-
First, open the application.
-
Second, enter your information.
-
Third, check that everything is correct.
-
Fourth, submit the form.
Anniversaries and Birthdays
-
They celebrated their 25th wedding anniversary last month.
-
The company is celebrating its 50th anniversary this year.
-
We organized a party for her 18th birthday.
Centuries
-
The printing press transformed Europe during the 15th century.
-
Many important inventions appeared during the 19th century.
-
Technology has developed rapidly in the 21st century.
Larger Ordinal Numbers
Ordinal numbers are not limited to small numbers. They can also describe positions involving much larger numbers.
-
She was the 101st person to register.
-
This is the show’s 200th episode.
-
He finished 123rd in the competition.
-
The organization celebrated its 150th anniversary.
These examples show that ordinal numbers can be written either in words (first, second, third) or with numerals and suffixes (1st, 2nd, 3rd), depending on the context and writing style.
FAQs About Ordinal Numbers
What are ordinal numbers?
Ordinal numbers are numbers that show position, order, or rank in a sequence. Examples include first (1st), second (2nd), third (3rd), and fourth (4th).
What are the suffixes for ordinal numbers in English?
The four ordinal number suffixes are -st, -nd, -rd, and -th.
Examples include:
-
1st
-
2nd
-
3rd
-
4th
-
21st
-
22nd
-
23rd
-
24th
Why is 11 written as 11th instead of 11st?
Numbers ending in 11, 12, and 13 are exceptions to the usual ordinal suffix pattern. They use -th.
Therefore:
-
11th
-
12th
-
13th
The rule also applies to larger numbers such as 111th, 112th, and 113th.
Is it 21st or 21th?
21st is correct. Because 21 does not end in 11 and its final digit is 1, it takes the suffix -st.
Is it 22nd or 22th?
22nd is correct. Numbers ending in 2 generally take -nd, except numbers ending in 12.
For example:
-
22nd
-
32nd
-
42nd
But:
-
12th
-
112th
Is it 23rd or 23th?
23rd is correct. Numbers ending in 3 generally take -rd, except numbers ending in 13.
For example:
-
23rd
-
33rd
-
43rd
But:
-
13th
-
113th
What is the difference between cardinal and ordinal numbers?
Cardinal numbers show quantity or tell us how many, while ordinal numbers show position or order.
For example:
-
one → first
-
two → second
-
three → third
-
four → fourth
In the sentence “I have three books,” three is a cardinal number. In “I am reading the third book,” third is an ordinal number.
How do you write ordinal numbers in words?
Ordinal numbers can be written as words, such as first, second, third, fourth, fifth, tenth, twentieth, and twenty-first.
Compound ordinal numbers are normally hyphenated:
-
21st → twenty-first
-
32nd → thirty-second
-
43rd → forty-third
Do ordinal numbers use apostrophes?
No. Do not place an apostrophe between a number and its ordinal suffix.
Incorrect: 1’st, 2’nd, 3’rd
Correct: 1st, 2nd, 3rd
Is 1st written with the number 1 or the letter I?
1st begins with the number 1, not the capital letter I.
Correct: 1st
Incorrect: Ist
When written completely in words, 1st is first.
Final Thoughts
Learning how to write ordinal numbers correctly is important for expressing position, order, rank, and sequence in English. Ordinal numbers appear frequently in dates, rankings, floors, anniversaries, centuries, and everyday instructions.
Remember the basic pattern:
-
Numbers ending in 1 usually take -st: 1st, 21st, 31st
-
Numbers ending in 2 usually take -nd: 2nd, 22nd, 32nd
-
Numbers ending in 3 usually take -rd: 3rd, 23rd, 33rd
-
Most other numbers take -th: 4th, 10th, 24th
The important exceptions are numbers ending in 11, 12, and 13, which always take -th, as in 11th, 12th, 13th, 111th, 112th, and 113th.
With these rules in mind, it becomes much easier to choose between forms such as 1st, 2nd, 3rd, and 4th and use ordinal numbers correctly in your writing.
For more English grammar, vocabulary, and writing lessons, explore the related guides below.
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