# Esperanto numbers: 0–100, ordinals, dates and time

Source: https://esperantopedia.org/grammar/numbers/
Language: en
Updated: 2026-10-28

> Esperanto numbers use 13 words: nul, unu, du … dek, cent, mil. 20 is dudek, 2026 is du mil dudek ses. Plus ordinals, fractions, dates and clock time.

Esperanto counts with **13 basic words**: *nul* (0), *unu* (1) to *naŭ* (9), *dek* (10), *cent* (100) and *mil* (1000). The rule from the Fundamento (rule 4) is simple: numbers written **together multiply**, numbers written **apart add**. So *dudek* = 2 × 10 = 20, and *dek du* = 10 + 2 = 12.

Joined words multiply, separate words add

Number words never change: they take no plural *-j* and no accusative *-n*. *Mi havas du fratojn* – "I have two brothers". The one exception is *unu* in the sense "some": *unuj … aliaj* – "some … others" (PMEG).

To convert any number automatically, use the [number converter](https://esperantopedia.org/tools/numbers/).

## Numbers 0–10

| Number | Esperanto | Pronunciation |
|---|---|---|
| 0 | *nul* | [nul] |
| 1 | *unu* | [ˈu.nu] |
| 2 | *du* | [du] |
| 3 | *tri* | [tri] |
| 4 | *kvar* | [kvar] |
| 5 | *kvin* | [kvin] |
| 6 | *ses* | [ses] |
| 7 | *sep* | [sep] |
| 8 | *ok* | [ok] |
| 9 | *naŭ* | [naw] |
| 10 | *dek* | [dek] |
| 100 | *cent* | [tsent] |
| 1000 | *mil* | [mil] |

Every letter is pronounced, and *c* always sounds like "ts" (see the [alphabet](https://esperantopedia.org/learn/alphabet/)). *Ses* (6) and *sep* (7) are easy to confuse, so say them clearly.

## Numbers 11–20

Numbers 11–19 are *dek* plus a unit, written as two words.

| Number | Esperanto | Number | Esperanto |
|---|---|---|---|
| 11 | *dek unu* | 16 | *dek ses* |
| 12 | *dek du* | 17 | *dek sep* |
| 13 | *dek tri* | 18 | *dek ok* |
| 14 | *dek kvar* | 19 | *dek naŭ* |
| 15 | *dek kvin* | 20 | *dudek* |

## Numbers 21–100: one rule

Tens are one word: unit + *dek*. Any number from 21 to 99 is the ten, a space, then the unit.

| Tens | Esperanto | Example | Esperanto |
|---|---|---|---|
| 10 | *dek* | 14 | *dek kvar* |
| 20 | *dudek* | 21 | *dudek unu* |
| 30 | *tridek* | 35 | *tridek kvin* |
| 40 | *kvardek* | 47 | *kvardek sep* |
| 50 | *kvindek* | 58 | *kvindek ok* |
| 60 | *sesdek* | 64 | *sesdek kvar* |
| 70 | *sepdek* | 72 | *sepdek du* |
| 80 | *okdek* | 86 | *okdek ses* |
| 90 | *naŭdek* | 99 | *naŭdek naŭ* |
| 100 | *cent* | 100 | *cent* |

## Hundreds, thousands and millions

Hundreds also join into one word: *ducent* (200), *tricent* (300), *naŭcent* (900). Everything else is written separately. Thousands are always a separate word: *du mil* (2000), not *dumil* (PMEG). Do not use hyphens: *cent tridek du*, not *cent-tridek-du*.

| Number | Esperanto |
|---|---|
| 101 | *cent unu* |
| 365 | *tricent sesdek kvin* |
| 1887 | *mil okcent okdek sep* |
| 1905 | *mil naŭcent kvin* |
| 2026 | *du mil dudek ses* |
| 12 345 | *dek du mil tricent kvardek kvin* |
| 333 000 | *tricent tridek tri mil* |
| 1 000 000 | *unu miliono* |
| 1 000 000 000 | *unu miliardo* |

*Miliono* and *miliardo* are nouns, so they take *-j* and *da*: *dek milionoj da homoj* – "ten million people". Esperanto uses the long scale: *biliono* is 10¹², not the English "billion" (10⁹), which is *miliardo* (PMEG).

## Ordinal numbers: -a

Add the adjective ending *-a* to get ordinals: *unua* "first", *dua* "second", *tria* "third", *kvara*, *kvina*, *sesa*, *sepa*, *oka*, *naŭa*, *deka* "tenth". Ordinals agree like any [adjective](https://esperantopedia.org/grammar/nouns-adjectives/): *la unuaj tagoj*, *la sepan tagon*.

In compound ordinals PMEG recommends a hyphen as clearer: *dek-unua* "eleventh", *dudek-unua* "twenty-first". *Dudek unua* also appears. In figures, write *1-a*, *21-a*.

With *-e* you get adverbs: *unue* "firstly", *due* "secondly". With *-o* you get nouns: *unuo* "a unit", *dekduo* "a dozen", *cento* "a hundred".

## Fractions, multiples and groups

Rule 4 of the Fundamento adds three [suffixes](https://esperantopedia.org/grammar/suffixes/) for numbers and the preposition *po*.

| Form | Meaning | Examples |
|---|---|---|
| *-on-* | fraction | *duono* "half", *triono* "a third", *kvarono* "a quarter", *tri kvaronoj* "three quarters" |
| *-obl-* | multiple | *duobla* "double", *trioble* "three times as much", *dekobla* "tenfold" |
| *-op-* | group | *duope* "in pairs", *triopo* "a trio", *kvarope* "four together" |
| *po* | each, distributive | *po du pomoj* "two apples each" |
| *-foj-* | times (a root, not a suffix) | *dufoje* "twice", *trifoje* "three times" |

*-obl-* and *fojo* differ: *duobla pago* is a double payment, *dufoja pago* is a payment made twice (PMEG).

Esperanto uses a decimal comma: *3,5* is read *tri komo kvin*. Arithmetic is plain: *du plus du estas kvar* (2 + 2 = 4), *dek minus tri estas sep*, *sep dividite per du estas tri komo kvin* (PMEG).

## Dates

A date is *la* + ordinal + *de* + month (+ year). The word *tago* "day" is left out.

- *la sepa de Oktobro 2026* – "7 October 2026"
- written: *la 7-a de Oktobro 2026*
- *Hodiaŭ estas la unua de Majo.* – "Today is the first of May."

When the date answers "when?", it takes *-n*: *Ni venos la sepan de Oktobro* – "We will come on 7 October". In letters: *merkredon, la 26-an de Novembro 1997* (PMEG). Years are read as normal numbers: *en 1887* = *en mil okcent okdek sep*. Month and weekday names are on [days and months](https://esperantopedia.org/phrases/days-months/).

## Telling the time

Hours are ordinal numbers with *la*: "the third (hour)". Words like *horo* and *minutoj* are usually dropped (PMEG).

| Esperanto | English |
|---|---|
| *Kioma horo estas?* | "What time is it?" |
| *Estas la tria.* | "It's three o'clock." |
| *Estas la tria kaj dek kvin.* | "It's 3:15." |
| *Estas la tria kaj kvarono.* | "It's quarter past three." |
| *Estas la sepa kaj duono.* | "It's half past seven." |
| *Estas dek post la tria.* | "It's ten past three." |
| *Estas dek kvin antaŭ la deka.* | "It's quarter to ten." |
| *Je kioma horo?* – *Je la oka.* | "At what time?" – "At eight." |
| *la dek-kvina kaj dek kvin* | "15:15" |

Use *antaŭ* "before" and *post* "after", never *de*. "At" a time is *je* (see [prepositions](https://esperantopedia.org/grammar/prepositions/)).

## Examples in sentences

- *Mi havas du fratojn kaj unu fratinon.* – "I have two brothers and one sister."
- *La bileto kostas dudek kvin eŭrojn.* – "The ticket costs twenty-five euros."
- *Mia avino naskiĝis en mil naŭcent kvindek kvar.* – "My grandmother was born in 1954."
- *Ŝi loĝas en la kvina etaĝo.* – "She lives on the fifth floor."
- *Mi legis la libron dufoje.* – "I read the book twice."
- *Duono de la klaso estas malsana.* – "Half of the class is ill."
- *La trajno foriras je la tria kaj duono.* – "The train leaves at half past three."
- *La infanoj eniris po du.* – "The children came in two by two."

## Common questions

### How do you count to 10 in Esperanto?
*Unu, du, tri, kvar, kvin, ses, sep, ok, naŭ, dek.* Zero is *nul*.

### How do you say 2026 in Esperanto?
*Du mil dudek ses.* Thousands are always a separate word, so 2000 is *du mil*, not *dumil*.

### How do you say "first", "second" and "third"?
Add *-a* to the number: *unua*, *dua*, *tria*. "Twenty-first" is *dudek-unua*.

### What is a billion in Esperanto?
*Miliardo* (10⁹). *Biliono* means 10¹², because Esperanto follows the long scale.

### How do you tell the time in Esperanto?
Use *la* with an ordinal: *Estas la oka* – "It's eight o'clock". "At eight" is *je la oka*, and half past eight is *la oka kaj duono*.

## Sources

- [Fundamento de Esperanto – grammar in English (rule 4)](https://www.akademio-de-esperanto.org/fundamento/gramatiko_angla.html)
- [PMEG – Nombroj (numbers)](https://bertilow.com/pmeg/gramatiko/nombroj/index.html)
- [PMEG – Forms of number words](https://bertilow.com/pmeg/gramatiko/nombroj/vortetoj/formoj.html)
- [PMEG – O-word numbers (fractions, long scale)](https://bertilow.com/pmeg/gramatiko/nombroj/o-vortoj.html)
- [PMEG – A-word numbers (ordinals)](https://bertilow.com/pmeg/gramatiko/nombroj/a-vortoj.html)
- [PMEG – Hours](https://bertilow.com/pmeg/gramatiko/nombroj/horoj.html)
- [PMEG – Dates](https://bertilow.com/pmeg/gramatiko/nombroj/datoj.html)
- [PMEG – Mathematical expressions](https://bertilow.com/pmeg/gramatiko/nombroj/matematiko.html)
- [PMEG – Suffix OBL](https://bertilow.com/pmeg/vortfarado/afiksoj/sufiksoj/obl.html)