Spanish fractionsLas fracciones

In both Spanish and English, there’s a lot of overlap between fractions and ordinals: the vast majority of these two types of numbers share the same word. In English, they are identical from "third" on up, while in Spanish they’re the same starting with cuarto.

Spanish fractions

half 1/2   una mitad
a third 1/3   un tercio
a fourth 1/4   un cuarto
a fifth 1/5   un quinto
a sixth 1/6   un sexto
a seventh 1/7   un séptimo
an eighth 1/8   un octavo
a ninth 1/9   un noveno
a tenth 1/10   un décimo

Creating fractions

Most Spanish fractions up to décimo are similar to their corresponding cardinal numbers but as you can see in the list above, there is no consistent method for creating them.

Starting at onceavo, that changes: you can create fractions by adding –avo to the cardinal number:

      cardinal add -avo
an eleventh 1/11   once un onceavo
a twelfth 1/12   doce un doceavo
a twentieth 1/20   veinte un veinteavo
a thirtieth 1/30   treinte un treinteavo

This works up to but not including one hundredth (1/100), which is un centésimo.

 Spanish has two words for "half":

1) la mitad (de)  (noun)

la mitad de los estudiantes   half of the students
Compré una pizza anoche y comí la mitad.   I bought a pizza last night and ate half (of it).

2) medio  (adjective)

Medio has a feminine form, media, but no plural forms: it can be used only with singular nouns.

Quiero un medio bocadillo.   I want half a sandwich.
Hay media manzana en la mesa.   There’s half an apple on the table.

Other than la mitad and medio/media, all Spanish fractions are masculine and must be preceded by a number. When it’s more than one, the fraction is plural:

2/3   dos tercios
3/4   tres cuartos

When fractions are used with the feminine noun parte, they act as adjectives and thus change to agree with it:

una tercia parte   a third
una octava parte   an eighth
tres décimas partes   three tenths

When any fraction other than medio is followed by a noun, the preposition de is needed as a go-between.

3/4 of the students   tres cuartos de los estudiantes
2/5 of the book   dos quintos del libro

 Spanish fractions and ordinal numbers are abbreviated differently. The fraction un quinto can only be abbreviated 1/5, whereas the ordinal el quinto is shortened to 5o.


Beginning with "fourth," Spanish fractions are identical to ordinal numbers, other than the type of article:

  • a fourth = un cuarto
  • the fourth = el cuarto

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