Ordinal numbers tell you the order of things — first, second, third. In Spanish they behave like adjectives: they agree in gender and number, and two of them lose their final letter before a masculine noun. Beyond tenth, everyday Spanish quietly switches to ordinary counting numbers.

Here is the full picture, from primero to the practical shortcuts.

First to tenth

  • 1st: primero — first
  • 2nd: segundo — second
  • 3rd: tercero — third
  • 4th: cuarto — fourth
  • 5th: quinto — fifth
  • 6th: sexto — sixth
  • 7th: séptimo — seventh
  • 8th: octavo — eighth
  • 9th: noveno — ninth
  • 10th: décimo — tenth

Gender and number agreement

Ordinals are adjectives, so they match the noun in gender and number. All four endings are possible:

Feminine singular: la primera vez — the first time · Masculine plural: los primeros días — the first days · Feminine plural: las segundas oportunidades — second chances · Masculine singular: el quinto capítulo — the fifth chapter.

The apócope: primer and tercer

Before a masculine singular noun, primero and tercero drop the final -o. This is called the apócope.

  • primero → primer: el primer día — the first day
  • tercero → tercer: el tercer piso — the third floor

But the full form returns with feminine or plural nouns: la primera semana, los primeros pasos, la tercera puerta. No other ordinal shortens this way.

Beyond ten

The higher ordinals exist, and you'll see two accepted spellings:

  • 11th: undécimo / decimoprimero — eleventh
  • 12th: duodécimo / decimosegundo — twelfth
  • 13th: decimotercero — thirteenth
  • 20th: vigésimo — twentieth

In real life, though, Spanish speakers usually stop using ordinals after tenth and switch to the plain cardinal number placed after the noun:

  • floor 20: el piso veinte (not el vigésimo piso)
  • chapter 15: el capítulo quince
  • the 25th anniversary: el aniversario número veinticinco

Where ordinals really shine

  • Floors: vivo en el segundo — I live on the second floor
  • Centuries and monarchs (Roman numerals): Carlos V is read Carlos Quinto; Felipe II is Felipe Segundo — but above ten, cardinals take over: Alfonso XIII is Alfonso Trece.
  • Rankings and sequences: el primer puesto — first place

Common mistakes

  • Forgetting the apócope: it's el primer día, not el primero día.
  • Shortening the wrong forms: only masculine singular shortens — never la primer vez (say la primera vez).
  • Overusing high ordinals: el vigésimo piso sounds stiff; el piso veinte is natural.
  • Dropping accents: keep them on séptimo, décimo, undécimo, vigésimo.

Memory tip: think "primer and tercer lose their -o for the men" — masculine singular only.

👉 Read also: Spanish Numbers 1–100 and Hardest parts of Spanish grammar.

Frequently asked questions

When do primero and tercero become primer and tercer?

Only directly before a masculine singular noun: el primer día, el tercer piso. With feminine or plural nouns they keep the full form: la primera vez, los primeros días.

Do I need ordinals for high numbers?

Rarely. After tenth, Spanish usually uses cardinals after the noun: el piso veinte, el capítulo quince. The high ordinals exist but sound formal or literary.

How are kings and centuries read aloud?

Up to ten, use ordinals: Carlos V is Carlos Quinto. From eleven onward, use cardinals: Alfonso XIII is Alfonso Trece, and the 21st century is el siglo veintiuno.