Cardinal numbers
A1 Los números cardinales 13 / 49
In short
Learn 0-15 as unique words; 16-29 are written as a single word (dieciséis, veintitrés); from 31 up you insert y only between the tens and the units (treinta y cuatro).
The rule
Step 1 - 0 to 15 each have their own name (see the table). There is no pattern here - memorize them.
Step 2 - 16 to 29 are written as one word. Four of them carry an accent: dieciséis, veintidós, veintitrés, veintiséis. (These come from the old “diez y seis”; today the one-word spelling is standard.)
Step 3 - From 30 up you write three words, joining tens and units with y - and y appears only between tens and units:
treinta y uno · cuarenta y cinco · noventa y nueve
There is no y after the hundreds: ciento treinta (never “ciento y treinta”).
cien vs ciento. Use cien for exactly 100 and before a noun, mil, or millones: cien euros, cien mil, cien millones. Use ciento to keep counting from 101 to 199: ciento uno, ciento cincuenta y dos.
Hundreds 200-900 agree in gender with the noun they count. Note the three irregular ones: quinientos (500), setecientos (700), novecientos (900):
doscientos libros · doscientas casas · quinientas personas
mil (“thousand”) is invariable and takes no “un”: mil, dos mil, cien mil - never “un mil.” It never agrees: tres mil casas. A hundred from 200 to 900 next to mil still agrees with the counted noun, in either order: doscientas mil personas, mil quinientas hojas, mil quinientos folios.
millón / millones are nouns, so they need de before the counted noun: un millón de euros, dos millones de personas. (Drop de if another number follows: un millón doscientos mil habitantes.)
uno -> un / una. uno drops the -o to un before a masculine noun and becomes una before a feminine noun - also inside compounds: un libro, veintiún años, treinta y un días; una casa, veintiuna sillas, treinta y una personas. On its own it stays uno: - ¿Cuántos? - Uno.
Prices with a fractional part use con: 12,50 = doce con cincuenta; 3,25 = tres con veinticinco. The currency goes unsaid once it is obvious: - ¿Cuánto es? - Ocho con veinte.
Forms & patterns
0-15
| 0 cero | 1 uno | 2 dos | 3 tres |
|---|---|---|---|
| 4 cuatro | 5 cinco | 6 seis | 7 siete |
| 8 ocho | 9 nueve | 10 diez | 11 once |
| 12 doce | 13 trece | 14 catorce | 15 quince |
16-31 (one word up to 29)
| 16 dieciséis | 17 diecisiete | 18 dieciocho | 19 diecinueve |
|---|---|---|---|
| 20 veinte | 21 veintiuno | 22 veintidós | 23 veintitrés |
| 24 veinticuatro | 25 veinticinco | 26 veintiséis | 27 veintisiete |
| 28 veintiocho | 29 veintinueve | 30 treinta | 31 treinta y uno |
Tens
| 30 treinta | 40 cuarenta | 50 cincuenta |
|---|---|---|
| 60 sesenta | 70 setenta | 80 ochenta |
| 90 noventa | 100 cien | 1000 mil |
Hundreds (agree in gender)
| 100 cien / ciento | 200 doscientos/-as | 300 trescientos/-as |
|---|---|---|
| 400 cuatrocientos/-as | 500 quinientos/-as | 600 seiscientos/-as |
| 700 setecientos/-as | 800 ochocientos/-as | 900 novecientos/-as |
Big numbers: 1000 mil · 2000 dos mil · 1 000 000 un millón · 2 000 000 dos millones.
Examples
| Español | English |
|---|---|
| Tengo veintiún años. | I am twenty-one years old. |
| Hay treinta y dos alumnos. | There are thirty-two pupils. |
| Cuesta cien euros. | It costs one hundred euros. |
| Estamos en la página ciento tres. | We are on page one hundred and three. |
| Quinientas personas vinieron. | Five hundred people came. |
| Repartieron doscientas mil bolsas. | They handed out two hundred thousand bags. |
| La ciudad tiene un millón de habitantes. | The city has a million inhabitants. |
| La entrada cuesta doce con cincuenta. | The ticket costs twelve fifty. |
Common mistakes
- cien uno -> ciento uno - use ciento (not cien) from 101 to 199; cien is exactly 100.
- un mil euros -> mil euros - “one thousand” is just mil, never “un mil.”
- doscientos casas -> doscientas casas - hundreds from 200 to 900 agree in gender with the noun.
- veintiuno años -> veintiún años - uno shortens to un (with an accent) before a masculine noun.
- un millón euros -> un millón de euros - millón/millones need de before the counted noun.
- ciento y treinta -> ciento treinta - y appears only between tens and units, never after the hundreds.
Tips
- Two joins to remember: 16-29 = one word; from 31 up = spaced with y between tens and units.
- cien points at something big (a noun, mil, millones); ciento keeps counting (101-199).
- Gender agreement touches only uno and the hundreds 200-900 - the rest never change.
- Say a year in normal chunks: 2025 = dos mil veinticinco.