Numbers in Spanish: everything you need to know

Numbers in Spanish can be quite tricky for Spanish students as there are lots of small changes that you need to be aware of to use them correctly. I’m here to teach you everything you need to know, looking at lots of common problems I’ve seen students have and giving you lots of different rules to help conquer this difficult area of the language.

Throughout this article, I provide lots of different examples to ensure that you learn the rules and don’t have any doubts about anything. I have not given you a full list of every number, however – the reason for this is that you can easily look up specific numbers that you want to know using a site such as WordReference.

Here is an index of all of the things I’m going to cover, so if you are only interested in learning one specific thing you can skip to that section!

I’m going to give you the numbers 1 to 10 here, as they will be used throughout the article so you can use them as a reference:

I’m also going to put here a video I made that speaks about a lot of these different patterns, in case you would prefer to learn some of it in this way:

Let’s get started!

Uno to un/ una

As we can see above, the number one in Spanish is ‘uno’. So if we are counting up from one, this is the word we will use (uno, dos, tres…).

However, this is only the case if the number is by itself. If it is followed by a noun the word will look different and will change depending on whether the noun is masculine or feminine.

We’ll look at if we have a masculine noun first, and we’ll use the noun ‘libro’ (book). When we want to say “one book”, we would say:

Un libro

So the ‘uno’ loses the ‘o’ when it’s followed by a masculine noun.

What about when it’s followed by a feminine noun such as ‘manzana’ (apple)? In this case, we would say:

Una manzana

So the ‘o’ at the end of the word changes to an ‘a’.

What you might notice is that these are also the words to say “a” or “an” in Spanish. So these two Spanish phrases could also translate to English as “a book” and “an apple”.

Pattern for numbers 21 – 29

The numbers 21 to 29 are all very similar which can help a lot with remembering them. The number 20 is ‘veinte’. We are going to use this as our base to form all of the numbers up to 29. 

We take this ‘veinte’ and change our final E to an i, giving us ‘veinti’. Then all we have to add to the end of this word are the corresponding numbers 1 to 9 to form each of our numbers 21 to 29. I’ll give you some examples to show what I mean.

If we want to form the number 21, we take our ‘veinti’ and add to the end of this the number 1. From the start of our post, we know that the number 1 is ‘uno’ – so the number 21 is going to be:

21 = Veintiuno

We can do the same for the number 28. The number 8 is ‘ocho’, so our number 28 is going to be:

28 = Veintiocho

Below is the full list:

*You can see that three of these numbers have an accent added. These accents are just to keep the stress on the end of the word, as without the accent these numbers would be pronounced differently.

Pattern for numbers 31 – 99

From the number 30 onwards, it becomes very easy to form our two-digit numbers in Spanish. All we need is our multiple of 10, plus the word for “and”, plus the relevant number between 1 and 9. Again, I’ll give you lots of examples to demonstrate this.

First let’s look at our multiples of 10, which I’m going to give you all the way up to 90. You’ll be able to see these are quite closely related to their corresponding units number (e.g. cuatro and cuarenta (4 and 40) are similar words):

Next we need our Spanish word for “and”, which is very simple being only one letter long: 

And = Y

In case you’re not sure, this is pronounced as the letter E would be in the English ABC song.

Finally, we need our numbers 1 to 9, which are at the start of the article. So now, forming any number between 30 and 99 is very simple. As our first example, if we want to say the number 31 in Spanish, we would take our tens number (‘treinta’) followed by the word for “and” (‘y’) followed by our units number, which in this case is one (‘uno’). So we get:

31 = treinta y uno

Easy! It works the exact same for any other numbers too. I’ll give you a good few examples below just so you can see this pattern in more detail:

Once you remember this pattern it becomes very easy to form these numbers.

This will be very useful for speaking about how old people are in Spanish. Below are plenty of examples using these numbers to speak about how old people are:

I am 36 years old = Tengo treinta y seis años

My brother is 54 years old = Mi hermano tiene cincuenta y cuatro años

They are 89 years old = Tienen ochenta y nueve años

Numbers ending in one (apart from 11)

As we saw previously, when the number 1 is followed by a noun it changes, and the change depends on whether the noun is masculine or feminine.

In fact, this is not only the case for the number 1, but also any number ending in ‘uno’! This means that all numbers ending in a 1, EXCEPT for numbers that end in 11, will have to change when they’re followed by nouns! Here are some examples of the change:

So you can see that, as with the number 1, these numbers change to ‘un’ and ‘una’ depending on the gender of the noun following it!

One number that works slightly differently is the number 21, or any larger numbers ending in 21 (e.g. 121, 5621). The masculine form of these numbers will look slightly different:

21 = veintiuno

21 books = veintiún libros

21 t-shirts = veintiuna camisetas

The number 100 in Spanish

The number 100 is a number that confuses Spanish learners as it looks slightly different depending on what comes after it. But don’t worry, this isn’t just random – we are again going to look at some rules for forming the word so you can adapt it to lots of different situations.

The place to start is the number 100 in Spanish if it is by itself:

100 = cien

One sentence in which you would see it in this form would be the translation of “Number 100, please” if you were in a numbered queue, for example:

Número cien, por favor

Now how about when it is followed by a noun? Luckily this is very easy – if we are saying we have 100 of something, whether the noun is masculine or feminine, the word will look exactly the same! We don’t need to change anything. Some examples are:

Simple, right? The reason Spanish students get confused is that if ‘cien’ comes before a number that is smaller than it (i.e. all that comes after it are tens and units, not thousands or millions), then it changes slightly. I’ll give you some examples to demonstrate this:

Therefore we need to say ‘ciento’ in all of these number. You can also notice that, unlike in English, in Spanish, we don’t need to say “one hundred and” – we never say ‘ciento y’. Instead, we just follow the ‘ciento’ directly with the one- or two-digit number that follows it.

Using multiples of 100

It’s also important to spend time speaking about how multiples of 100 work in different situations. The numbers by themselves are usually quite easy to form – we usually take the corresponding number 1 to 9 and add this to the front of the plural of ‘ciento’, which is ‘cientos’. There are some irregulars though, so I’ll write them out in full here (with the irregulars in bold):

Again, as with the number 100, if it is followed by tens and units we don’t need to add an ‘y’:

462 = cuatrocientos sesenta y dos

574 = quinientos setenta y cuatro

902 = novecientos dos

If these multiples of one hundred are followed by masculine nouns, they don’t change:

300 books = trescientos libros

800 men = ochocientos hombres

246 boys = doscientos cuarenta y seis chicos

However, if they are followed by feminine nouns there is a change. They also change even if they are followed by tens and units, as I will show here:

600 t-shirts = Seiscientas camisetas

400 chairs = Cuatrocientas sillas

736 women = Setecientas treinta y seis mujeres

So what you can see is that all of these numbers change to agree with the feminine noun – using the standard feminine plural adjective ending -as instead of the standard masculine ending –os.

How to speak about thousands

Thousands are something that also cause problems when students are learning Spanish numbers. The main problem is trying to translate the number 1,000 into Spanish.

In English, we always say “one thousand” or “a thousand” and it would be wrong to say the number without one of these two things in front of it. However, in Spanish, it is much more straightforward – we only need one word:

1000 = mil

We would NEVER say ‘un mil’ or anything like that – we only need this single word. The word would not change in front of nouns, either, whether these nouns are masculine or feminine:

Forming multiples of one thousand are a lot more similar to English. As how in English we say “two thousand”, “three thousand” and so on, in Spanish we just need to follow the corresponding units number by the word ‘mil’, as we can see in these examples:

2,000 = dos mil

3,000 = tres mil

5,000 = cinco mil

Then it is also very easy to form different 4-digit numbers given everything we have looked at so far:

Speaking about years in Spanish

Another common usage of numbers in Spanish is when we are speaking about years, for example in what year something happened, what year we were born or in what year you are going to do something.

In English, we usually form 4-digit years by splitting them into two 2-digit numbers. Some examples are:

However, this NEVER happens in Spanish. Instead of breaking it down, we just say the year as a 4-digit number – there is no other way to say it. So looking at the numbers above, we have:

MUCH easier, I would say – but of course difficult to remember as a native English speaker!

As I said, a common reason we might use years is to say the year in which you were born. If you were born in 1991, as an example, you might say:

I was born in 1991 = Yo nací en mil novecientos noventa y uno

Forming millions

Since this is a COMPLETE guide, we’re also going to look at millions and how to form these.

To say “one million”, unlike with thousands, you would keep the “one”, so it would be:

1,000,000 (one million) = un millón

Multiples of a million are also easy to form. We simply say the number of millions that we have followed by the plural of ‘millón’, which is the word ‘millones’.

As our first example, if we have “two million” we would say:

2 million = dos millones

I’ll give you lots of other examples here:

These numbers don’t change if other numbers come after them:

10,564,321 (ten million five hundred and sixty-four thousand three hundred and twenty-one) = diez millones quinientos sesenta y seis mil trescientos veintiuno

Because we have already looked at each of the other aspects individually, all we have to do is combine these parts together.

We need to be careful when we have millions directly followed by a noun, though, for example when we are speaking about millions of pounds or dollars.

In Spanish, we don’t just follow the millions directly with the noun, but we instead have to add something in:

A million dollars = Un millón de dólares

So we have to add in a ‘de’, which means we’re literally saying “ a million OF dollars. Some other examples:

5 million people = cinco millones de personas

10 million episodes = diez millones de episodios

150 million days = ciento cincuenta millones de días

This only is the case if the millions are directly followed by a noun. If there are other numbers following the millions, there is no need for the ‘de’:

Ten million five hundred thousand episodes (10,500,000) = diez millones quinientos mil episodios

Five million two hundred people (5,000,200) = cinco millones doscientas personas

Be careful with billions

Our final things to look at the Spanish word for “a billion” as this is definitely something that causes a lot of confusion.

There is a very similar word in Spanish which is:

Un billón

In English, when we say “a billion” we are speaking about a thousand millions (i.e. one million multiplied by 1,000 = 1,000,000,000). However, in Spanish this word ‘un billón’ usually refers to a million millions – so it actually means A TRILLION!

Un billón = a trillion

How would we say “a billion” then? When speaking in Spanish, you would have to instead say “a thousand millions”, so it would look like this:

One billion (1,000,000,000) = Mil millones

Easy once you know it but very confusing before you do.

Given the above translation of “one billion”, here are some other examples of other multiples of billions:

And of course, if these billions are followed by a noun, we must add in a ‘de’:

A billion dollars = mil millones de dólares

7 billion people = siete mil millones de personas

So there you have it! The complete guide to using numbers in Spanish. Of course there is a lot of information there, but if you learn these rules you won’t have any more problems with forming numbers in Spanish. I hope this is all useful!