Cardinal Numbers in Spanish

In Brief

Spanish cardinal numbers tell you how many: cero, uno, dos, and so on. From 31 to 99, join the tens and units with y (treinta y dos), but write 16–29 as single words (dieciséis, veintiuno). Before a noun, uno can become un or una, and exact 100 is cien, not ciento.

Overview

Cardinal numbers are the ordinary counting numbers used for quantities, prices, ages, addresses, phone numbers, and many other everyday details. They answer ¿cuántos? or ¿cuántas? (“how many?”). A noun is a word for a person, place, thing, or idea, such as libro (“book”) or hora (“hour”).

Numbers from 0 to 100 are an A1 foundation. Most Spanish numbers are built from a small set of patterns, so you do not need to memorize one hundred unrelated words. The key stages are the special forms up to 15, the single-word forms from 16 to 29, and the tens + y + units pattern from 31 onward.

English-speaking learners should pay special attention to spacing and accents. English writes “twenty-one” with a hyphen, while Spanish writes veintiuno as one word and treinta y uno as three words, with no hyphen. Spanish also changes the form of uno next to some nouns, something English “one” does not do.

How It Works

Zero to fifteen: learn the basic forms

These forms provide the building blocks for the rest of the system.

Number	Spanish	Number	Spanish
0	cero	8	ocho
1	uno	9	nueve
2	dos	10	diez
3	tres	11	once
4	cuatro	12	doce
5	cinco	13	trece
6	seis	14	catorce
7	siete	15	quince

Sixteen to nineteen: single words

The numbers 16–19 historically combine diez with a unit, but today they are written as one word.

Number	Spanish	Helpful breakdown
16	dieciséis	diez + seis
17	diecisiete	diez + siete
18	dieciocho	diez + ocho
19	diecinueve	diez + nueve

Only dieciséis carries a written accent in this group. The accent mark shows where the stressed syllable falls.

Twenty to twenty-nine: one word again

Use veinte for 20. For 21–29, attach the unit directly to veinti-.

Number	Spanish	Number	Spanish
20	veinte	25	veinticinco
21	veintiuno	26	veintiséis
22	veintidós	27	veintisiete
23	veintitrés	28	veintiocho
24	veinticuatro	29	veintinueve

Remember the written accents in veintidós, veintitrés, and veintiséis. There are no hyphens or spaces inside these numbers.

Thirty to ninety-nine: tens + y + units

First learn the round tens:

Number	Spanish	Number	Spanish
30	treinta	60	sesenta
40	cuarenta	70	setenta
50	cincuenta	80	ochenta
		90	noventa

To add a unit from 1 to 9, use:

tens + y + unit

• 31: treinta y uno
• 45: cuarenta y cinco
• 68: sesenta y ocho
• 99: noventa y nueve

Here y means “and.” It appears between the tens and units, but not after a round ten: 40 is simply cuarenta, not cuarenta y. Unlike English, standard Spanish uses spaces rather than hyphens.

Uno, un, and una

When counting on its own, use uno: cero, uno, dos. Before a masculine singular noun, uno shortens to un. This shortening is called apocope (dropping the end of a word).

• uno — one, when counting or standing alone
• un libro — one book
• una mesa — one table

The same change affects numbers ending in 1:

Number alone	Before a masculine noun	Before a feminine noun
veintiuno	veintiún libros	veintiuna páginas
treinta y uno	treinta y un libros	treinta y una páginas
noventa y uno	noventa y un días	noventa y una noches

Notice the accent in veintiún. In separated forms such as treinta y un, un has no accent. With a feminine noun, una agrees with the noun’s grammatical gender (its masculine or feminine word class), even if the thing is not a person.

When the number is not directly before the noun, the full form may return: Tengo treinta y uno (“I have thirty-one”).

One hundred: cien or ciento?

Use cien for exactly 100, including directly before a noun:

• cien — one hundred
• cien euros — one hundred euros
• cien personas — one hundred people

Use ciento when another number follows: ciento uno (101), ciento veinte (120). Although those compounds go beyond this article’s core 0–100 range, the distinction explains why exact 100 must not be called ciento.

Examples in Context

Spanish	English	Note
Tengo dos hermanos.	I have two brothers / siblings.	A basic quantity before a noun.
La entrada cuesta quince euros.	Admission costs fifteen euros.	Price with a number.
Hay dieciséis estudiantes en la clase.	There are sixteen students in the class.	Dieciséis is one word and has an accent.
Mi hermana tiene veintidós años.	My sister is twenty-two years old.	Spanish uses tener (“to have”) for age.
Necesitamos veintitrés sillas.	We need twenty-three chairs.	Veintitrés is one word.
Vivo en el número veintiocho.	I live at number twenty-eight.	A street or building number.
El billete cuesta treinta y dos euros.	The ticket costs thirty-two euros.	From 31 onward, use y between tens and units.
Hay cuarenta personas en total.	There are forty people in total.	A round ten takes no y.
Compró cincuenta y una flores.	She bought fifty-one flowers.	Una agrees with feminine flores.
El curso dura sesenta y un días.	The course lasts sixty-one days.	Uno becomes un before masculine días.
La habitación tiene ochenta metros cuadrados.	The room is eighty square metres.	Measurement with a round ten.
Solo quedan noventa y nueve entradas.	Only ninety-nine tickets remain.	Tens + y + units.
Cien personas respondieron.	One hundred people replied.	Exact 100 is cien.
¿Cuántos años tienes? — Tengo veintiuno.	How old are you? — I’m twenty-one.	Veintiuno stands alone here.

Common Mistakes

Writing 21–29 as separate words or with a hyphen

• Wrong: veinte y dos / veinti-dos
• Right: veintidós
• Why: The numbers 21–29 are single words. Some also require a written accent: veintidós, veintitrés, veintiséis.

Leaving out y after thirty

• Wrong: treinta dos euros
• Right: treinta y dos euros
• Why: From 31 to 99, use y between a nonzero tens digit and the units digit.

Adding y to a round ten

• Wrong: cuarenta y euros
• Right: cuarenta euros
• Why: Use y only when a unit follows: cuarenta y uno, but cuarenta.

Using uno directly before a masculine noun

• Wrong: uno libro / treinta y uno días
• Right: un libro / treinta y un días
• Why: Uno shortens to un before a masculine singular noun, including inside a larger number.

Ignoring feminine agreement in numbers ending in one

• Wrong: veintiún personas
• Right: veintiuna personas
• Why: Before a feminine noun, the final uno becomes una. This difference is absent from English and is easy to overlook.

Saying ciento for exact 100

• Wrong: ciento euros
• Right: cien euros
• Why: Exact 100 is cien. Reserve ciento for a number above 100 when something follows, such as ciento dos.

Usage Notes

In everyday speech, number words follow the same basic rules across the Spanish-speaking world. Pronunciation varies by region, but spellings such as dieciséis and veintidós remain standard.

The singular article un/una can overlap with the number “one.” Context normally makes the meaning clear: Necesito un café can mean “I need a coffee” without stressing the quantity. If contrast matters, speakers can add emphasis: Quiero uno, no dos (“I want one, not two”).

For telephone numbers, room numbers, codes, and similar strings, speakers may read digits one by one or group them in locally familiar ways. A zero inside a number is cero. Because grouping conventions differ, asking someone to repeat the digits is often safer than expecting one universal format.

With ages, Spanish says tener + number + años, literally “to have ... years”: Tengo treinta años. Do not copy the English structure “I am thirty” as soy treinta.

Beyond the Basics: Larger Numbers and Special Uses

You do not need to master this section at A1, but the 0–100 patterns continue into larger numbers.

After 100, use ciento + number: ciento uno, ciento dieciséis, ciento treinta y dos. Exact 100 stays cien. The shortened form also appears before larger scale words when the amount is exactly one hundred of them: cien mil (“one hundred thousand”) and cien millones (“one hundred million”).

The hundreds from 200 onward normally agree in gender with a following noun:

• doscientos libros — two hundred books
• doscientas páginas — two hundred pages

This agreement does not change cien/ciento: cien páginas, ciento una páginas. Larger numbers therefore combine two agreement points: the hundreds may have a feminine form, and a final 1 may become un or una.

Spanish often uses cardinal numbers where English might expect an ordinal number (a number showing order, such as “first” or “second”). Chapters, rooms, buses, and years commonly use cardinals: capítulo cinco (“chapter five”), habitación doce (“room twelve”), el año dos mil. This is a usage choice rather than a new way of forming the number.

For 100 percent, cien por cien and ciento por ciento are both used, with regional and stylistic preferences. As a beginner, recognizing both is enough.

Practice Tips

1. Build numbers in three blocks. Memorize 0–15, then practise 16–29 as single words, then generate 31–99 from the tens. Say a random two-digit number aloud and check whether it needs y.
2. Practise nouns with numbers ending in 1. Make three-column sets such as veintiuno, veintiún libros, veintiuna casas. This trains the form change instead of treating it as an isolated rule.
3. Use real information. Read prices, ages, addresses, scores, and times in Spanish. Write ten figures as digits first, then spell them out, paying special attention to spaces and accent marks.

Related Concepts

• Next step: Ordinal Numbers — learn numbers that express order, such as “first” and “second.”
• Next step: Time & Dates — use cardinal numbers to tell the time, give dates, and discuss schedules.