Fractions and multiples in Spanish are built on top of ordinals and a small set of Latinate forms. The system is largely regular from a third upward, with one productive trap (medio agrees in gender like an adjective), one set of borderline forms above ten (-avo), and a decimal/fraction notation that uses the comma where English uses the dot. Multiples like doble and triple are equally tidy — but they stop being productive after quíntuple, and beyond that natives switch to veces. This page covers all of it.
Halves: medio and la mitad
Spanish has two words for "half," and they are not interchangeable:
- medio / media — adjective form. Goes before a noun and agrees in gender. Medio kilo, media hora, medio litro, media taza.
- la mitad — noun form. Means "the half" as a thing. La mitad de la tarta, la mitad de los estudiantes.
Necesito medio kilo de tomates y media barra de pan.
I need half a kilo of tomatoes and half a loaf of bread.
Llevo media hora esperando el autobús.
I've been waiting for the bus for half an hour.
La mitad de mis amigos ya no vive en Madrid.
Half my friends don't live in Madrid anymore.
Solo quiero la mitad, no me cabe más.
I only want half, I can't fit any more.
There is also a noun un medio ("one half" as a mathematical fraction), which appears in arithmetic and recipes but rarely in everyday speech:
Un medio más un medio es uno.
One half plus one half is one.
Fractions from one third to one tenth
These are formed with the masculine ordinal — tercero → tercio, cuarto, quinto — though some lose their final -o in the fraction form. Memorise them as a block.
| Fraction | Spanish |
|---|---|
| 1/2 | un medio (or: la mitad) |
| 1/3 | un tercio |
| 1/4 | un cuarto |
| 1/5 | un quinto |
| 1/6 | un sexto |
| 1/7 | un séptimo |
| 1/8 | un octavo |
| 1/9 | un noveno |
| 1/10 | un décimo |
Casi un tercio de la población vota en blanco o se abstiene.
Almost a third of the population votes blank or abstains.
Le toca un cuarto de la herencia a cada hermano.
Each sibling gets a quarter of the inheritance.
Solo un quinto de los candidatos aprobó el examen.
Only a fifth of the candidates passed the exam.
The numerator is a cardinal (un, dos, tres…), the denominator is the fraction word. The fraction word agrees in number when the numerator is plural: un tercio but dos tercios, tres cuartos, cinco octavos.
Bebe dos litros y medio de agua al día, lo cual son diez cuartos de litro.
He drinks two and a half litres of water a day, which is ten quarter-litres.
La empresa redujo el personal en tres cuartos.
The company cut its staff by three quarters.
When the fraction modifies a quantity (two thirds of the students), use de:
Dos tercios de los empleados teletrabajan ahora.
Two thirds of the employees work from home now.
Tres cuartas partes del país está cubierto de bosque.
Three quarters of the country is covered in forest. (literary)
The phrase tres cuartas partes uses the feminine plural form because parte is feminine. It's a slightly more formal alternative to tres cuartos.
Fractions above ten: the -avo forms
From eleven downward the system shifts, and Spanish has two competing series:
- Latinate ordinals — undécimo, duodécimo, decimotercero… — formal/legalistic, used for ranks and articles of law.
- -avo series — un onceavo, un doceavo, un treceavo… — used as fractions. These exist precisely because the Latinate ordinals sound stiff when you're just talking about portions.
| Fraction | Spanish (-avo) | Latinate alternative |
|---|---|---|
| 1/11 | un onceavo | un undécimo |
| 1/12 | un doceavo | un duodécimo |
| 1/13 | un treceavo | un decimotercero |
| 1/15 | un quinceavo | un decimoquinto |
| 1/20 | un veinteavo | un vigésimo |
| 1/100 | un centésimo | (no -avo form in standard use) |
| 1/1000 | un milésimo | — |
Cada participante recibe un doceavo del premio.
Each participant gets one twelfth of the prize.
El error es menor que un milésimo.
The error is smaller than one thousandth.
In everyday speech, fractions above 1/10 are almost always rephrased: uno de cada doce ("one in twelve"), el 8 por ciento ("8 per cent"), uno entre veinte ("one in twenty"). The -avo series is real and recognisable but you don't have to deploy it.
Decimals vs fractions
Spanish uses the comma as the decimal separator and the period (or a space) as the thousands separator — the opposite of English. Four-digit years are an exception with no separator at all.
| Number | Spanish | Read aloud |
|---|---|---|
| 0.5 | 0,5 | cero coma cinco |
| 3.14 | 3,14 | tres coma catorce / tres coma uno cuatro |
| 1,000 | 1.000 (or 1 000) | mil |
| 2,500.75 | 2.500,75 | dos mil quinientos coma setenta y cinco |
| 2024 (year) | 2024 | dos mil veinticuatro |
La temperatura media del cuerpo es de 36,5 grados.
The average body temperature is 36.5 degrees.
El precio del piso ha subido hasta los 285.000 euros.
The flat's price has risen to 285,000 euros.
Fractions and decimals are equivalent — un medio = 0,5 = cero coma cinco — but the choice carries register: scientific and statistical writing strongly prefers decimals, recipes and everyday measurement prefer fractions, and finance freely mixes both.
Multiples: doble, triple, cuádruple, quíntuple
For "twice," "three times," "four times" something, Spanish has a tidy adjective/noun series — but it runs out of steam fast.
| × | Spanish |
|---|---|
| ×2 | doble |
| ×3 | triple |
| ×4 | cuádruple |
| ×5 | quíntuple |
| ×6 | séxtuple (rare) |
| ×7+ | generally rephrased as siete veces más |
Esto cuesta el doble que el año pasado, no hay quien lo entienda.
This costs double what it did last year, it makes no sense.
Le pagan el triple por el mismo trabajo.
They pay him triple for the same job.
Pidió un café doble con leche.
She ordered a double coffee with milk.
These forms can work as adjectives (una habitación doble — "a double room") or as nouns with the article (el doble, el triple). The construction el doble de + noun is the multiplier pattern:
Necesitamos el doble de tiempo para terminar.
We need double the time to finish.
Hay el triple de turistas que el año pasado.
There are three times as many tourists as last year.
Beyond five, even Spanish speakers reach for the productive [number] veces ("[number] times"):
Gana siete veces más que un profesor.
She earns seven times more than a teacher.
Esta ciudad es diez veces más grande que mi pueblo.
This city is ten times bigger than my village.
Por as multiplier
The preposition por is the multiplication sign in arithmetic, and it also signals multiplicative scaling in everyday talk.
Tres por cuatro son doce.
Three times four is twelve.
La ciudad creció por dos en una década.
The city doubled in size in a decade. (informal)
In recipes and measurements, por can also distribute a quantity ("per"):
Una cucharada por persona, no más.
One spoonful per person, no more.
For arithmetic operations in full, see Math and Measurements.
Common mistakes
❌ Necesito media kilo de azúcar.
Incorrect: kilo is masculine, so medio (not media) is required.
✅ Necesito medio kilo de azúcar.
I need half a kilo of sugar.
❌ Espero media de hora.
Incorrect: don't insert de between medio and the noun.
✅ Espero media hora.
I'll wait half an hour.
❌ La mitad de tarta.
Incorrect: la mitad requires the article before the noun (la mitad de la tarta).
✅ La mitad de la tarta.
Half of the cake.
❌ Dos tercio de los empleados.
Incorrect: tercio agrees with the cardinal — dos tercios.
✅ Dos tercios de los empleados.
Two thirds of the employees.
❌ Tres comma catorce.
Incorrect: the word is coma (Spanish), not comma.
✅ Tres coma catorce.
Three point one four.
❌ Cuesta el doble como antes.
Incorrect: comparison after doble/triple uses que, not como.
✅ Cuesta el doble que antes.
It costs double what it did before.
How Spanish fractions and multiples differ from English
English has a single agreement-free fraction system (half a kilo, a quarter of the cake), but Spanish forces you to choose between medio (an adjective that agrees with the noun) and la mitad (a noun that takes de). Decimal punctuation is reversed: 3,14 in Spanish is 3.14 in English, and 1.000 in Spanish is 1,000 in English — a small visual difference that has caused real misunderstandings in invoices and contracts. The multiples series doble / triple / cuádruple / quíntuple parallels English double / triple / quadruple / quintuple and stops at roughly the same place; both languages reach for [number] times (or veces) once they run out of named multiples. The peculiarity unique to Spanish is the -avo suffix, which exists solely as a fraction marker — un doceavo is a twelfth, but el doceavo is wrong for "the twelfth." That semantic split between ordinal and fraction has no equivalent in English.
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Start learning Spanish→Related Topics
- Cardinales 0-30A1 — The first thirty cardinal numbers in Spanish — the irregular teens (once, doce, trece, catorce, quince), the dieci- fusions for 16–19, the veinti- fusions for 21–29, and the masculine/feminine agreement of uno.
- Cardinales 100+A2 — Hundreds, thousands, millions and billions in Spanish — the irregular hundreds (quinientos, setecientos, novecientos), gender agreement on the hundreds, the invariable mil, the de-construction with millón, the European decimal/thousands convention, and the false-friend trap with billón.
- Ordinales: primero, segundo, terceroA2 — How ordinal numbers work in Spanish — the first ten, apocope of primero/tercero, agreement, and why natives switch to cardinals after décimo.
- Matemáticas y medidasB1 — Arithmetic in Spanish (más, menos, por, entre), percentages, the metric system, how heights, weights and temperatures are expressed in Spain, and why imperial units don't belong.
- Concordancia: guía completaA2 — A reference for every Spanish adjective-agreement situation — one noun, multiple nouns, mixed genders, coordinated nouns, pre-nominal apocopation, and the resolution rules that keep the agreement chain consistent.