Money, Measures, and Quantities

This is where the number rules you have learned stop being abstract and start touching real life: paying for things, weighing things, measuring things. Two facts drive almost everything on this page. First, the currency word króna is feminine, so the moment a price ends in 1–4 you are forced to choose a feminine numeral — tuttugu og *ein króna, never *tuttugu og einn króna. Second, measurements and quantities lean heavily on the preposition *af ("of") — kíló *af eplum ("a kilo of apples") — but only where a bare genitive or a compound would not do the job more idiomatically. Get those two reflexes right and you can shop, cook, and read a price tag in Icelandic. (The bare cardinal forms themselves — how *einn, tveir, þrír, fjórir decline — live on their own pages; here we put them to work.)

króna is feminine — and that decides the numeral

Króna ("crown", the currency) is a weak feminine noun: singular króna, plural krónur. Because it is feminine, any numeral 1–4 attached to it must take its feminine form, and this is the single most frequent agreement task in everyday Icelandic money talk, because every price ending in 1–4 triggers it.

From 5 upwards the numeral stops changing (fimm, sex, sjö … krónur), so the agreement burden falls entirely on amounts ending in 1, 2, 3, 4. And it is the last digit that counts: tuttugu og ein króna (21), þrjátíu og tvær krónur (32), hundrað og þrjár krónur (103) — the feminine numeral is forced even inside a big number, because the unit it lands on is króna.

Reading prices: þúsund and hundruð

Real prices are large, and Icelandic builds them with hundruð ("hundreds") and þúsund ("thousand"). A price like 2 500 kr. is read tvö þúsund og fimm hundruð krónur ("two thousand and five hundred krónur"). Two points trip learners up:

• þúsund and hundrað are neuter nouns, so the numeral in front of them is neuter: tvö þúsund (neuter "two"), þrjú hundruð (neuter "three"). The final króna, by contrast, is feminine — so a single big price can mix a neuter "two" (with þúsund) and a feminine "one" (with króna).
• The little og ("and") is usually inserted before the last element: tvö þúsund *og fimm hundruð, fimm hundruð **og fimmtíu*.

Writing prices: the thousands separator is a period

This is a formatting trap for English speakers. Icelandic, like most of Europe, uses a period (full stop) as the thousands separator and a comma as the decimal mark — the exact opposite of English. So 2 500 krónur is written 2.500 kr., and 1 250 000 is 1.250.000. The decimal comma rarely appears with króna (prices are whole numbers), but it does in measurements: 1,5 lítrar ("1.5 litres").

The currency is abbreviated kr. (lower-case, with a period), written after the number: 2.500 kr. You will also see ISK in financial and international contexts.

Measurement nouns and their agreement

The everyday units carry gender, and the numeral 1–4 agrees with it just as with króna. The two you meet most are the masculine -i units and the neuter kíló/gramm:

So "one" alone takes three different shapes depending on the unit: einn metri (masc.), eitt kíló (neut.), ein króna (fem.). The same goes for hálfur ("half"), which agrees too: hálfur lítri (masc.), hálft kíló (neut.).

The partitive af — and when to skip it

To say "a [quantity] of [stuff]", Icelandic uses af ("of") plus the dative: kíló *af eplum ("a kilo of apples"), hálfur lítri **af mjólk* ("half a litre of milk"). This is the natural pattern when you are measuring out an amount of an uncountable or bulk substance.

But af is not always the idiomatic choice. Where Icelandic has a ready compound noun, that is usually preferred over an af-phrase: a glass of water is vatnsglas (water-glass), not typically glas af vatni; a cup of coffee is kaffibolli (coffee-cup). And after a plain measurement word with a count noun you often need no preposition at all, just a bare genitive or the noun directly. So reach for af with bulk quantities (kíló af, lítri af, poki af — "a bag of"), but let a compound take over when the language already has one.

How this differs from English

English keeps "of" everywhere — a kilo of, a cup of, a glass of, a lot of — so the temptation is to translate af into every quantity phrase. Icelandic is choosier: it uses af for bulk amounts but reaches for a compound (kaffibolli, vatnsglas) where English would say "of". English also has no gender, so the idea that the word "two" changes shape — tveir metrar, tvær krónur, tvö kíló — for the same number is genuinely foreign; you have to track the unit's gender every time. And the number formatting is mirror-reversed: where English writes 2,500.5, Icelandic writes 2.500,5. None of these is hard once flagged, but each is a place where the English reflex produces a wrong Icelandic sentence.

Common Mistakes

Key Takeaways

• króna is feminine (ein króna, tvær krónur), so every price ending in 1–4 forces a feminine numeral — tuttugu og ein króna, never *einn króna. This is a constant agreement task.
• From 5 up the numeral is invariant (fimm, sex … krónur); only the last digit 1–4 triggers agreement.
• Big prices use neuter þúsund and hundruð (tvö þúsund, þrjú hundruð), so one price can mix a neuter "two" with a feminine "one".
• Formatting is mirror-reversed from English: period = thousands (2.500 kr.), comma = decimal (1,5 lítrar); the abbreviation is kr. after the number.
• Measurement units carry gender too: einn metri (kk), eitt kíló (hk), ein króna (kvk); hálfur/hálft agrees the same way.
• Use the partitive af + dative for bulk quantities (kíló af eplum, lítri af mjólk), but prefer a compound where one exists (kaffibolli, not bolli af kaffi).