A sweet & simple guide to cardinal & ordinal numbers in English

Do you ever find yourself unsure of when to use ordinal versus cardinal numbers in English?

While you might already be able to count in English with no problem, it can sometimes be tricky to figure out when to use cardinal numbers and when to use ordinal numbers. In other words, sometimes we say “one,” while sometimes we say “first,” so how do we know which is the right one?

In this handy guide, we’ll go over the definition of both cardinal and ordinal numbers and provide you with plenty of examples and linguistic tidbits to help you use all English numbers expertly. Oh, and we’ll also provide you with massive lists of cardinal and ordinal numbers along with their pronunciation so you can start using them in your everyday conversations right away.

Without further ado, let’s get started!

Table of contents

• Cardinal numbers in English
• Ordinal numbers in English
• When should you contract ordinal numbers?
• Ordinal vs. cardinal numbers: the key differences
• Practical exercises

Cardinal numbers in English

First things first, we’ve got to cover the basics: cardinal numbers. These are the numbers that you likely think of when you think of numbers: one, two, three, etc. These help us discuss things when their order doesn’t really matter. For example, if you want three apples, it doesn’t really make a difference what order they come in. In English, we use Arabic numerals to write them in almost all cases.

What are the cardinal numbers in English? How do you write and pronounce them?

Cardinal numbers are used for counting, so use them any time you need to count how many siblings and cousins you have, how many fruits and vegetables you want to buy, and how many cups of coffee you want to order. Here’s a big list with dozens of cardinal numbers and their pronunciation in English:

Example sentences of cardinal numbers in English

Let’s review some sample sentences of cardinal numbers in English now that you know what cardinal numbers are:

• I only have one child
• Can you meet me here in two hours?
• I’ve already had three cups of coffee today, so I’ll have some tea instead.
• My dad gave me four presents for my birthday.
• My flight was delayed for five hours.
• They say cats have nine lives, and this one seems to be on his first!
• I will be going to New York for ten days.
• I’ve told you a thousand times, don’t play ball in the street!

Bonus: Numerical sequences

Another common way of counting things is by using numerical sequence words like “once,” “twice” or “thrice.” These words mean one time, two times, and three times, respectively, and they can be used any time you want to mention something that happened between one and three times. Unfortunately, thrice is the highest that these words will go, so you won’t be to use these numerical sequence words for things that happened four or more times!

Here are some examples of how these words are used:

• I will only say this once, so pay close attention!
• I like this movie so much I watched it twice in one day.
• I can’t believe I ran into her not once, not twice, but thrice in one week!

Ordinal numbers in English

You learned about cardinal numbers first, so now we’re going to learn about ordinal numbers second. No less important than cardinal numbers, these types of numbers help us discuss things when their order does matter. For example, even though winning isn’t everything, we all want to place first in any contest or competition, right? Placing second or third is also okay, but there’s nothing like placing first! Ordinal numbers help us in situations like these where the order does actually matter.

What are ordinal numbers in English? How do you write and pronounce them?

Ordinal numbers are used to order items in a sequence, such as first, second, third, and so on. Think of the word order when you think of ordinal and you’ll surely never forget these numbers. After the first three numbers, ordinal numbers are usually made by adding -th at the end of the cardinal number. For example, four becomes fourth, six becomes sixth, and ten becomes tenth.

However, this rule isn’t infallible, and there are a few exceptions that don’t obey this rule, like fifth, ninth, and twelfth. Here’s a list of dozens of the most important ordinal numbers along with their pronunciation in English:

Example sentences of ordinal numbers in English

Now that you’re familiar with all the key ordinal numbers in English, let’s take a look at some example sentences so you know how to use them like a true native:

• This is my first time in California!
• I can’t believe we ran into each other at the supermarket for a second time.
• Welcome to the third annual Homestead Elementary Math Competition!
• I won my school’s spelling bee contest for a fourth time.
• John Glenn was the fifth person to go to space.
• New Zealand is the tenth country I’ve visited this year.
• I’m very interested in neoclassical art from the eighteenth century.
• For the hundredth time, lock the door when you get home!

Bonus: Umpteenth

While reviewing ordinal numbers, there’s one more “number” that you should keep in mind: umpteenth. While this isn’t a number, it is commonly used in sentences in place of a normal ordinal number. It simply means a very large and undefined number in a succession, generally used to emphasize the enormity of the number. For example:

• I had to water your plant for the umpteenth time this month because you keep forgetting to do it yourself.

In the example sentence above, it doesn’t matter how many times the person had to water the plants that month — the use of umpteenth simply emphasizes that it’s an unreasonably high number. This is an informal word that you may use in everyday conversations, but it’s probably best to keep it away from academic or formal settings.

When should you contract ordinal numbers?

Ordinal numbers can be expressed in numerals just like cardinal numbers. To do this, simply add the last two letters of the ordinal number to the Arabic numeral, such as 1st, 2nd, 3rd, etc. Informally, you can use these any time you want to save time and space, like when planning out your calendar or writing to-do lists. Formally, you’ll want to write out the names of the ordinal numbers from one to nine and use the contraction for ten and above.

Ordinal vs. cardinal numbers: the key differences

Now that you’re familiar with the broad differences between ordinal and cardinal numbers, let’s take a deep dive into what makes them different from each other.

1. Purpose

Perhaps paradoxically, numbers aren’t always used to express quantity. As you now know, ordinal numbers denote the order within a sequence, but they don’t really tell us any information about quantity. Take a look at the following examples:

• This train has ten cars, which makes it one of the longest in the world.
• I’m waiting for you in the second car of the train.

In the first sentence, we know exactly how many cars the train has: ten. However, in the second sentence, we don’t really know how many cars the train has. There could be four, six, eight or even just two cars in that train, but that doesn’t matter. The most important thing is to help the other person locate you in relation to the other cars of the train.

That’s one thing to keep in mind when dealing with ordinal numbers. The missing context can sometimes be deceiving, since you don’t really know the total quantity of the nouns you’re referring to. Take this from someone who once placed third in a three-person singing contest!

2. Formation

Ordinal numbers are typically formed by adding the suffix “-th” to the corresponding cardinal number. For example, four becomes fourth and ten becomes tenth. However, there are a few irregular forms that you should keep in mind. The following ordinal numbers have irregular spellings:

• One → First
• Two → Second
• Three → Third
• Five → Fifth
• Eight → Eighth
• Nine → Ninth
• Twelve → Twelfth

Also, keep in mind that numbers ending in one, two, or three, will also have the same ordinal ending as the corresponding single-digit number. For example:

• 21st → Twenty-first
• 33rd → Thirty-third
• 52nd → Fifty-second

3. Usage

Although we’ve already taken a look at the general use of each of the types of numbers, let’s go into more detail about when you’re supposed to use ordinal vs. cardinal numbers in English:

When to use cardinal numbers

In general, you’ll want to use cardinal numbers when the quantity of the noun in question is important. Here are some concrete examples:

• Counting: Use cardinal numbers when you want to count things like the number of pizza slices you ate for dinner, the number of friends you want to invite to your birthday party, and the times you’ve been to the beach this summer.
• Measurement: Use cardinal numbers when measuring in feet, meters, kilometers, miles — anything you want! Even when measuring time, as in “it’s been three hours since I got here.”
• Dates: This one’s a bit tricky. You should use cardinal numbers when writing out dates, as in “July 5, 1995,” but you should use ordinal numbers when speaking, as in “July fifth, 1995.” More on this below.

When to use ordinal numbers

Although cardinal numbers are more common than ordinal numbers, these last ones have a far wider variety of uses. Here are some of the most common:

• Sequential lists: As mentioned earlier, you’ll want to use ordinal numbers any time the sequence of nouns matters, as in the order of the train cars in our example from earlier.
• Dates: Dates are almost always spoken with ordinal numbers, such as “September twenty-second” or “May fourth.” They can also be written informally with cardinal numbers, such as “I’ll be in Houston on the fourteenth” or “I land on the third.”
• Ranking: Rankings of nouns always go with ordinal numbers. Use these when ranking things, such as people in a competition, rankings in the military, and classes of travel.
• Position: Use ordinal numbers to talk about positions relative to something. For example, “take the second exit on the right” or “I’m the third in line.”
• Names: Formal names where lineage is critical also use ordinal numbers, typically written with Roman numerals, like Louis XVI.
• Floors of buildings: Floors of buildings also use ordinal numbers, since the sequence of floors is very important. For example, “I live on the third floor.”
• Periods of time: Periods of time use ordinal numbers only when the sequence is critical. For example, “This is only my second day working here, I can’t run the store on my own!”
• Birthdays and anniversaries: Birthdays and anniversaries are, by definition, sequential in nature, so they will always use ordinal numbers.
• Fractions: Finally, fractions also use ordinal numbers. For example, ¼ is one fourth and ⅛ is one eighth. Note that ½ is one half and ¼ can also be one quarter.