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 in Spanish (1st, 2nd, 10th...)

Learn about fractions in Spanish 

Look at these examples with 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 lower number (the denominator) is plural if the top number (the numerator) is greater than one. (dos quintos)


Half and Double in Spanish

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 either "de" or "el/la".
 
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

cinco séptimosfive sevenths

cuatro décimosfour tenths

Want to make sure your Spanish sounds confident? We’ll map your knowledge and give you free lessons to focus on your gaps and mistakes. Start your Brainmap today »

Learn more about these related Spanish grammar topics

Examples and resources

Un cuarto de la población votó en contra.A quarter of the population voted against.
Me he comido dos tercios de la pizza.I had two thirds of the pizza.
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.
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.
tres cuartosthree quarters
dos décimostwo tenths
un tercioa third
tres octavosthree eighths
un cuartoa quarter
un séptimoone seventh
dos quintostwo fifths
cinco séptimosfive sevenths
La mitadHalf
cuatro décimosfour tenths
El dobleDouble
Let me take a look at that...