Spanish vocabulary · Beginner

How to Say Eighteen in Spanish

Dieciocho · noun · dyeh-see-OH-choh

The Spanish word for eighteen is 'dieciocho,' a compound number formed from 'diez' (ten) and 'ocho' (eight). In Spanish, numbers from sixteen to nineteen are written as single compound words.

Pronounce it as dyeh-see-OH-choh, with four syllables and the stress on the third. The word flows as one unit rather than two separate parts.

Mi sobrina cumple dieciocho años mañana.

My niece turns eighteen tomorrow.

How Native Speakers Use Dieciocho

Real example sentences across three contexts you'll actually run into.

Age milestone

A los dieciocho años puedes votar en España.

At eighteen years old you can vote in Spain.

Discussing legal voting age.

Counting items

Necesitamos dieciocho sillas para la reunión.

We need eighteen chairs for the meeting.

Counting objects needed for an event.

Telling time

El vuelo sale a las dieciocho horas.

The flight departs at eighteen hundred hours.

Using 24-hour time format.

Avoid These Mistakes When Using Dieciocho

Splitting the word

Incorrect: Tengo diez y ocho años.

Correct: Tengo dieciocho años.

Numbers from sixteen to nineteen in Spanish are single compound words. 'Diez y ocho' is an outdated form — modern Spanish uses 'dieciocho.'

Spelling error

Incorrect: Tiene diesiocho primos.

Correct: Tiene dieciocho primos.

The correct spelling uses 'ci' in the middle, not 'si.' The compound comes from 'diez' becoming 'dieci-' when joined.

Lock in eighteen Vocabulary with the Parrot Method

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See Dieciocho used by native speakers

Parrot's short-form videos feature native speakers using dieciocho in real situations. Context-based exposure beats flashcards, you hear Mi sobrina cumple dieciocho años mañana. while watching someone live the moment, connecting meaning, sound, and rhythm at once.

Save, review, repeat, stay consistent

Tap any word to save it. Parrot's spaced-repetition system surfaces it right before you'd forget, no manual flashcard creation. The watch, parrot back, save, review cycle turns recognition into fluency at 2.7x the speed of traditional study.

Common Questions About eighteen in Spanish

Why is eighteen written as one word in Spanish?
Spanish numbers from sixteen to nineteen are contracted into single words — dieciséis, diecisiete, dieciocho, diecinueve — following the pattern of 'dieci' plus the ones digit.
Is eighteen the legal adult age in Spanish-speaking countries?
In most Spanish-speaking countries, turning dieciocho marks the legal age of adulthood, granting rights to vote, sign contracts, and other adult responsibilities.
How do you say eighteenth in Spanish?
The ordinal form is 'decimoctavo' for formal usage, though in everyday speech people often say 'el dieciocho' or 'número dieciocho' instead of the ordinal.