Esperanto grammar Part of Chapter 25

CEFR B1-B2

3 min read

Test yourself (18 questions)

Esperanto Measurements: Units, Decimals and Rates Aloud

By Michael McGettrickUpdated 12 October 2026

Esperanto measures with the international system: , . Decimals take a comma, read komo, and a rate puts in front of the whole amount: is 120 km/h.

SI prefixthe endingWhat do the colours mean?
WrittenSaid
1 km
25 cm
12,34 komo
120 km/h
10² = 100 .

Quick check

Now use it: three quick questions on the chart above. The full practice is further down.

Spot the mistake

0/3

Each sentence has one wrong word. Tap it.

The SI prefixes

SI prefixWhat do the colours mean?

The prefixes work exactly as they do internationally, and only on units of measurement:

SmallLarge
  1. mili-
  2. centi-
  3. deci-
  4. hekto-
  5. kilo-
  6. mega-
PrefixValueExample
mega-megaherco
-
hekto-hektogramo
deci-odecimetro
centi-o
mili-omiligramo
  • . - The town is ten kilometres away.

PMEG lists the full set, up to kveta- (ten to the thirtieth) and down to kvekto-. Several of the words are already official, such as and , and PMEG says most such words can be treated as roots in their own right.

Two oddities. Hektaro, a hectare, and megomo, a megohm, are irregular, but the regular hektoaro and megaomo are also usable. And miriametro, ten thousand metres, became an official root although neither it nor its prefix is used any more.

Decimals: the comma read as komo

Esperanto writes a decimal comma, as most of Europe does, and reads it komo. The digits after it are read one at a time:

WrittenSaid
12,34 komo
46,987 komo
9403,5 km komo
8,6 kg komo

So 46,987 is never komo . A half can also be said as a fraction:

  • - 9403.5 kilometres
  • gramoj - 8 kilograms 600 grams

Rates: po at the front

marks a rate, and it goes in front of the whole amount. The unit then takes , or a plain adverb:

WrittenSaid
120 km/h
120 km/h
20 $/kg

Traditionally the amount after stays in the plain form: . Many speakers add the -n when the sentence calls for it, , and PMEG accepts both. can sometimes be left out, often with added:

  • . - The apples cost two dollars a .

The classic error copies English per and puts before the unit. Zamenhof's own example of the right form is 80 centimoj () , eighty centimes a pound.

Sums aloud

WrittenSaid
2 + 2 = 4 .
10 - 3 = 7 minus .
7 : 2 = 3,5 komo .
10² = 100 .
5³ = 125 .
√4 = 2 .

is the older verb for equals; and are commoner today.

Mistakes English speakers make

WrongRightWhy
komo a decimal comma: komo
before the amount
squared is an adverb

What to do next

  1. Read the numbers on a food label aloud, comma and all.
  2. Say your town's speed limit with ... .
  3. Then read numbers and fractions and multiples.

See also

Practise: test yourself

Build the word

0/3

Build the unit from its pieces.

  1. a kilometre (a thousand metres)

    Accents optional - cx, gx, ux work for ĉ, ĝ, ŭ

    Your word is empty.

  2. a centimetre (a hundredth of a metre)

    Accents optional - cx, gx, ux work for ĉ, ĝ, ŭ

    Your word is empty.

  3. a kilogram (a thousand grams)

    Accents optional - cx, gx, ux work for ĉ, ĝ, ŭ

    Your word is empty.

Complete the story

0/4

Choose the word that fits each gap.

On the road

La aŭto veturas cent dudek kilometroj horo. Ĉe la vendejo, la pomoj kostas po du dolaroj kilogramo. Dek estas cent.

Gap 1 of 4

Spot the mistake

0/3

Each sentence has one wrong word. Tap it.

Pick the right one

0/3

How do you read it aloud?

  1. 12,34

  2. 5³ = 125

  3. 120 km/h

Matching

0/5

Match each prefix to its value.

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Frequently asked questions

How do you say in Esperanto?
. The prefixes attach to units just as they do internationally: , , milimetro, . Several of these words are already official Esperanto roots, and PMEG says most such words can be treated as roots in their own right.
How do you read a decimal number in Esperanto?
Esperanto writes a decimal comma and reads it as komo. The digits after it are read one by one: 12,34 is komo , and 46,987 is komo , not komo .
How do you say per hour in Esperanto?
in front of the whole amount and use or before the unit: , 120 km/h. You can also say . A price works the same way: .
How do you say plus, minus and equals in Esperanto?
, or plus . minus . komo . is the older verb for equals; and are commoner today.
How do you say squared and cubed in Esperanto?
With the adverbs and : , ten squared is a hundred; , five cubed is a hundred and twenty-five. The square root is : .