Numbers in Spanish: The Complete Guide from 0 to a Trillion

Numbers in Spanish look like hundreds of words to memorise. They are really fifteen words and four patterns, plus a short list of irregulars worth knowing by name. This is the complete reference: every number from 0 to 100 with native audio, then the hundreds, thousands, millions, and the billion trap that makes newspapers misreport figures by a factor of a thousand. Then ordinals, fractions, decimals, percentages, dates, phone numbers, and the numbers Spanish speakers consider unlucky. Bookmark it and you will not need another page.

The short answer: 1 is uno▶, 10 is diez▶, 100 is cien▶, 1000 is mil▶, and a million is un millón▶. Now the detail.

Spanish Numbers 1 to 100 (Complete Table)

Every number, with a play button on each. Tap any of them to hear a native voice.

1 to 20

21 to 40

41 to 60

61 to 80

81 to 100

Nothing above is guesswork: once you know 1 to 15 and the tens, every other number on that table is built by rule. Here are the four rules.

Pattern 1: Sixteen Is Where Spanish Gets Logical

dieciséis▶ is literally diez y seis, "ten and six", crushed into one word. So are 17, 18 and 19:

• 16 = diez + seis = dieciséis
• 17 = diez + siete = diecisiete
• 18 = diez + ocho = dieciocho
• 19 = diez + nueve = diecinueve

Same trick in the twenties, with veinte worn down to veinti: veintiuno▶ (21), veintidós▶ (22), through veintinueve (29).

Pattern 2: From Thirty, Spanish Separates

At 31, the words split and a y ("and") appears. This is the most useful rule on the page:

• 31 = treinta y uno▶
• 42 = cuarenta y dos▶
• 99 = noventa y nueve▶

So 16 to 29 are one word, 31 to 99 are three. That asymmetry is the thing to drill.

Pattern 3: The Tens Are Almost Regular

From 40 up it is just the base number plus -enta: cuatro to cuarenta, seis to sesenta, siete to setenta, ocho to ochenta, nueve to noventa. Only treinta and cincuenta bend it. Spanish, unlike French, has a real word for every ten. Be grateful.

Pattern 4: Uno Changes Shape

Spanish numbers agree with what they count, and uno is the one that moves:

• un before a masculine noun: un libro, veintiún años
• una before a feminine noun: una mesa, treinta y una personas
• uno standing alone: ¿Cuántos? Uno.

You do not say uno libro. It is the most common numeric error learners make.

The Hundreds (100 to 1000)

Three rules live here:

1. cien vs ciento. Cien alone (cien euros). Ciento with anything following (ciento cinco). And no y after the hundred: ciento uno, never ciento y uno. The y only ever sits between tens and units.
2. The hundreds agree in gender. Doscientas personas, quinientas casas. This catches even advanced learners.
3. 500, 700 and 900 are irregular. They are the only ones. Drill them separately.

Combining is straightforward: 748 is setecientos cuarenta y ocho▶.

Thousands, Millions and Beyond

Three traps:

• mil never takes un. It is mil euros, never un mil euros. And it stays singular when counting: dos mil. The plural miles is only for vagueness: miles de personas.
• millón is the opposite. It takes un, it pluralises (dos millones), and it requires de before a noun: un millón de euros, never un millón euros. That de is compulsory and constantly dropped by learners.
• And then there is the billion.

The Billion Trap: A Billion Is Not Un Billón

This is the most consequential thing on this page, and it is not a subtlety. It is a factor of one thousand.

English uses the short scale. Spanish, French, German and most of continental Europe use the long scale.

Read that twice. English billion (10⁹) is Spanish mil millones, not billón. And Spanish billón (10¹²) is English trillion. The long scale is internally consistent: each new -illion is a million times the last, not a thousand.

So "Apple is worth three trillion dollars" is tres billones de dólares. A mistranslated billón has moved markets, and the press gets it wrong regularly.

Spanish does have un millardo▶ for 10⁹, officially recognised by the RAE, but almost nobody says it in practice. Use mil millones.

Ordinal Numbers

Above tenth, Spanish quietly gives up. Undécimo and duodécimo exist, but real speakers say el piso once, "floor eleven", using the plain cardinal. Nobody says vigésimo primero for 21st outside a legal document. This is a rare case where the lazy option is the native one.

Ordinals agree in gender and number: la primera vez, los primeros días.

Fractions, Decimals and Percentages

• From 1/5 up, fractions borrow the ordinals: un quinto, un sexto, un octavo. Past tenth they switch to -avo: un onceavo, un veinteavo.
• Decimals use a comma, and you say coma▶: 3,14 is tres coma catorce. Mexico increasingly follows the English dot.
• Thousands use a dot in Spain: 1.000.000.
• Percentages take an article: el veinte por ciento.

Pronunciation: What the Spelling Hides

Three details do most of the work.

The c in cinco and the z in diez. In Spain, both are a soft "th" as in "think": THEEN-ko, DYETH. In Latin America, both are a plain "s": SEEN-ko, DYESS. Neither is wrong. Pick the country you care about and stay consistent.

Written accents are stress instructions. dieciséis carries its accent on the last syllable: dyeh-see-SAYSS, not DYEH-see-sayss. Same with veintidós and veintitrés. Spanish tells you the rhythm in writing, if you know to look. Note veintiún keeps the accent while veintiuno does not need it.

Numbers arrive fast, and that is the real problem. You will not meet them one at a time. You will meet them in a price, a platform announcement, a phone number rattled off at speed. Recognising cuarenta y siete on a page is a completely different skill from catching it at a market stall.

This is exactly where written guides run out of road. A table teaches you to recognise; it does not teach you to produce, and it will never train your ear for a number thrown at you. The only fix is to hear a native say the whole number, then say it back out loud, several times, until it stops being a translation. That listen and repeat loop is called shadowing, and it is what turns sesenta y ocho from something you decode into something you simply hear. It is how the Hyperpolyglot app handles every phrase: real sentences, native audio, looped until they come out automatically. Available on iOS, Android, and Web.

The Numbers Spanish Speakers Treat as Special

• Tuesday the 13th, not Friday. In Spain and most of Latin America the unlucky day is martes trece▶. The proverb runs En martes trece, ni te cases ni te embarques: "on Tuesday the 13th, don't get married or set sail". Friday the 13th means nothing there.
• el gordo▶, "the fat one", is the top prize of the Spanish Christmas lottery. The winning number is national news every 22 December, and the draw is sung by schoolchildren.
• Roman numerals for centuries and monarchs. El siglo XXI is read el siglo veintiuno. Felipe VI is Felipe sexto.
• un googol▶ is a 1 followed by a hundred zeros. It gave Google its name, via a misspelling.
• infinito▶ for infinity, and menos cinco▶ for negative five.
• un quintillón▶ is 10³⁰ in Spanish, and yes, that is different from the English quintillion (10¹⁸) too. The long scale goes all the way down.

Common Mistakes to Avoid

1. Saying uno libro. It is un libro. Before a noun, uno shortens.
2. Saying un billón for a billion. It is mil millones. A billón is a thousand times bigger.
3. Forgetting de after millón. Un millón de euros, never un millón euros.
4. Saying cinco-cientos for 500. It is quinientos. Also setecientos (700) and novecientos (900).
5. Saying ciento y uno. The y only goes between tens and units: ciento uno, but treinta y uno.
6. Saying un mil. It is just mil.
7. Mixing the Spain "th" and the Latin American "s" in one sentence. Pick a country and commit.

Bonus: The Numbers You Will Actually Use First

• Prices: ¿Cuánto cuesta? Dos euros con cincuenta▶.
• Age: Tengo treinta y cinco años▶. Spanish has years rather than is them.
• Phone numbers: Spaniards read them in pairs, sesenta y seis, veinticuatro..., not digit by digit.
• Time: Son las tres y veinte▶, "it's three twenty".
• Dates use cardinals, not ordinals: el tres de mayo▶, "the three of May". Only the 1st can be primero, in parts of Latin America.
• Ordering: Una mesa para cuatro▶.

Learn 1 to 15, the -enta pattern and the y rule, then keep quinientos and mil millones on a sticky note. Drill them with real audio until they arrive as sounds rather than sums, and Spanish numbers stop being arithmetic and start being language.

Keep Reading

• Language Islands -- the real-sentence method that turns vocabulary into actual conversations
• The Easiest Languages to Learn -- why Spanish is the usual starting point for English speakers
• The Shadowing Technique -- how to drill pronunciation until it becomes automatic