Expressing fractions in Spanish

Be careful not to mix up fractions (to describe a part of a whole: half, third, fourth...) and ordinal numbers (to describe an order/rank: 1st, 2nd, 3rd, 4th...).

For ordinal numbers, see Forming ordinal numbers (1st, 2nd, 10th...)

Look at these examples of fractions:

un tercioa third

un cuartoa quarter

dos quintostwo fifths

To express fractions in Spanish, you usually use both cardinal (un/dos/tres...) and ordinal numbers (cuarto/quinto...) the same way as in English (one fifth, two thirds...).

Note also that just like in English, the second number is plural if the first is. (dos quintos)


Half and Double

To say half and double we normally use the definite articles el and la.

La mitadHalf

El dobleDouble

Have a look at these examples to see fractions in context:

Me he comido dos tercios de la pizza.I had two thirds of the pizza.

Un cuarto de la población votó en contra.A quarter of the population voted against.

Puse solo la mitad de la harina en el bol.I only put half the (quantity of) flour in the bowl.

Ella tiene el doble de hermanos que él.She has twice as many siblings as he does.

Notice how, as we generally talk about a fraction "of" a whole, you will usually find "de" after the fraction.
 
Bear in mind that to say "half" [of something] you can also use "medio/media".

He cortado medio melón para nuestra cena.I cut half a melon for our dinner.

He cortado media sandía para nuestra cena.I cut half a watermelon for our dinner.

Notice how we use medio when we refer to a masculine noun (e.g., melón) and media when we refer to a feminine noun (e.g., sandía). It is only possible to use medio/a with singular nouns, not plural nouns:
"Medio pueblo salió a la calle a celebrar la fiesta."
"La mitad del pueblo salió a la calle a celebrar la fiesta."
"La mitad de los jóvenes salió a la calle a celebrar la fiesta."
"Medio/Medios jóvenes salieron a la calle a celebrar la fiesta."
Also notice above how medio/a are not followed by "de".
 
Here is a list of fractions from half to a tenth:
 
1/2    la mitad [de] - medio/-a
1/3    un tercio [de]
1/4    un cuarto [de]
1/5    un quinto [de]
1/6    un sexto [de]
1/7    un séptimo [de]
1/8    un octavo [de]
1/9    un noveno [de]
1/10  un décimo [de]
 
 Here are more examples of fractions:

tres cuartosthree quarters

dos décimostwo tenths

tres octavosthree eighths

un séptimoone seventh

Learn more about these related Spanish grammar topics

Examples and resources

Ella tiene el doble de hermanos que él.She has twice as many siblings as he does.
La mitadHalf
dos décimostwo tenths
Puse solo la mitad de la harina en el bol.I only put half the (quantity of) flour in the bowl.
dos quintostwo fifths
tres cuartosthree quarters
Me he comido dos tercios de la pizza.I had two thirds of the pizza.
un cuartoa quarter
He cortado media sandía para nuestra cena.I cut half a watermelon for our dinner.
Un cuarto de la población votó en contra.A quarter of the population voted against.
un séptimoone seventh
un tercioa third
He cortado medio melón para nuestra cena.I cut half a melon for our dinner.
El dobleDouble
tres octavosthree eighths

Q&A Forum 4 questions, 4 answers

BaC1Kwiziq community member

Singular / plural ?

Here you have:  la mitad de los alumnos fueron al viaje. 

Half the students went on the trip.
But also you gave la mitad de los jóvenes salió de la ciudad
Asked 1 month ago
InmaKwiziq team member

Hola Ba,

I imagine you are referring to the use of the verb in singular or plural in this case. 

With a quantifier + de + noun in plural, both the verb in the 3rd person singular and 3rd person plural are correct. Here are some examples:

La mitad de los habitantes se fue/se fueron a la ciudad.

Half the inhabitants left the city.

El 10 por ciento de las personas votó/votaron en contra del candidato.

10 per cent of the people/population voted against the candidate.

La mayoría de los niños fue/fueron a ese viaje.

The majority of the children went on that trip.

I hope it helped.

Saludos

Inma

Singular / plural ?

Here you have:  la mitad de los alumnos fueron al viaje. 

Half the students went on the trip.
But also you gave la mitad de los jóvenes salió de la ciudad

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LindaC1Kwiziq Q&A regular contributor

Medio vs la mitad de

In the quiz asking for “half a sandwich”, I put “la mitad de un bocadillo” instead of “medio bocadillo” and was marked incorrect.  

Is my answer in fact incorrect or just not what the answer was looking for? When we say “half a sandwich” in English, my understanding is that it is really shorthand for “half (of) a sandwich” and so I thought either “la mitad de” or “medio” would be correct - perhaps that is not true in Spanish?  

Thanks in advance for your explanation.

Asked 3 months ago
InmaKwiziq team member

Hola Linda

Sorry, the English should say "He ate half THE sandwich" not "half a sandwich". The two possible correct answers for "half the sandwich" are "medio bocadillo" and "la mitad del bocadillo". This is why yours was marked wrong. I will change the English so there is no confusion.

Gracias y saludos.

Inma

Medio vs la mitad de

In the quiz asking for “half a sandwich”, I put “la mitad de un bocadillo” instead of “medio bocadillo” and was marked incorrect.  

Is my answer in fact incorrect or just not what the answer was looking for? When we say “half a sandwich” in English, my understanding is that it is really shorthand for “half (of) a sandwich” and so I thought either “la mitad de” or “medio” would be correct - perhaps that is not true in Spanish?  

Thanks in advance for your explanation.

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EmanuelB2Kwiziq Q&A regular contributor

a mistake in an example?

salío should not be salió or salía?

Asked 5 months ago
InmaKwiziq team member

Indeed! Fixed.

Gracias

a mistake in an example?

salío should not be salió or salía?

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EmanuelB2Kwiziq Q&A regular contributor

Third example

I would like to point out that the third example does not contain any fraction.

Asked 5 months ago
InmaKwiziq team member

Thanks for reporting that Emanuel. That's fixed now.

Saludos

Inma

Third example

I would like to point out that the third example does not contain any fraction.

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