The regular comparison page showed the productive pattern — add -ari for the comparative, -astur for the superlative (ríkur → ríkari → ríkastur). This page covers the adjectives that don't follow it, and there is a cruel irony built in: the adjectives that compare irregularly are precisely the most common ones in the language — big, small, good, bad, old, young, long, high, much. You cannot avoid them; you use them in your first conversations. They split into two groups. The i-umlaut comparatives take the endings -ri / -stur with a changed stem vowel (stór → stærri → stærstur), and the suppletives replace the stem entirely (góður → betri → bestur). The good news: the umlaut group's vowel changes are the same i-umlaut you already met turning fótur into fætur — so half the work is done.
The i-umlaut comparatives: -ri / -stur with a changed vowel
These adjectives keep a regular shape — comparative in -ri, superlative in -stur — but front the stem vowel by i-umlaut. The triggering i was in the old comparative/superlative endings, so the vowel moves forward in the mouth: á/ó → æ, a → e, u → y, o → e. Here is the core set:
| Positive | Comparative (-ri) | Superlative (-stur) | Vowel change | Meaning |
|---|---|---|---|---|
| stór | stærri | stærstur | ó → æ | big → bigger → biggest |
| hár | hærri | hæstur | á → æ | high/tall → higher → highest |
| langur | lengri | lengstur | a → e | long → longer → longest |
| ungur | yngri | yngstur | u → y | young → younger → youngest |
| þungur | þyngri | þyngstur | u → y | heavy → heavier → heaviest |
| skammur | skemmri | skemmstur | a → e | short → shorter → shortest |
Look at the vowels in isolation: stærri fronts the ó of stór to æ; hærri fronts the á of hár to æ; lengri fronts the a of langur to e; yngri fronts the u of ungur to y. These are exactly the outcomes a learner already knows from noun plurals — bók → bækur (ó → æ), maður → menn (a → e). The mental move is identical; only the suffix differs.
Reykjavík er stærri en Akureyri.
Reykjavík is bigger than Akureyri. Comparative 'stærri' — ó fronts to æ.
Hvannadalshnjúkur er hæsti tindur landsins.
Hvannadalshnjúkur is the country's highest peak. Superlative 'hæsti' (weak/definite form of 'hæstur') — á → æ.
Þessi leið er lengri en hin.
This route is longer than the other. Comparative 'lengri' — a → e.
Litli bróðir minn er þremur árum yngri en ég.
My little brother is three years younger than me. Comparative 'yngri' — u → y.
The suppletives: memorise them as sets
The second group doesn't umlaut — it switches to a different stem the way English does in good → better → best. There is no logical shortcut here; you simply learn each chain as a fixed three-part set. These are the most frequent adjectives of all, so the investment pays off immediately:
| Positive | Comparative | Superlative | Meaning |
|---|---|---|---|
| góður | betri | bestur | good → better → best |
| illur / vondur | verri | verstur | bad → worse → worst |
| gamall | eldri | elstur | old → older → oldest |
| mikill | meiri | mestur | much/great → more → most |
| lítill | minni | minnstur | little/small → less/smaller → least/smallest |
| margur | fleiri | flestur | many → more → most |
Three observations make these stick. First, the good/bad pair is exactly English's: góður → betri → bestur maps cell-for-cell onto good → better → best, and vondur → verri → verstur onto bad → worse → worst — same suppletion, same idea, so they're easier than they look. Second, gamall → eldri → elstur ("old → older → oldest") is the most over-regularised by learners (you'll be tempted by *gamlari) — drill it until it's automatic, because you'll describe people's ages constantly. Third, the much/many distinction is split across two words: mikill → meiri → mestur for uncountable "much," and margur → fleiri → flestur for countable "many" — a split English collapses into a single more/most.
Þetta kaffihús er betra en hitt.
This café is better than the other. Comparative 'betra' (neuter of 'betri') — suppletive from 'góður'.
Veðrið er verra í dag en í gær.
The weather is worse today than yesterday. Comparative 'verra' (neuter of 'verri') — from 'vondur/illur'.
Hún er elsta systirin af fjórum.
She's the eldest of four sisters. Superlative 'elsta' (weak/definite of 'elstur') — from 'gamall'.
Amma er eldri en afi.
Grandma is older than Grandpa. Comparative 'eldri' — from 'gamall', not the regularised '*gamlari'.
Það er meiri snjór í ár en í fyrra.
There's more snow this year than last. Comparative 'meiri' — uncountable 'much/more', from 'mikill'.
Flestir Íslendingar tala ensku.
Most Icelanders speak English. Superlative 'flestir' (plural of 'flestur') — countable 'most', from 'margur'.
How these decline
The declension rules carry over unchanged from the regular page, so there's little new to learn here. The comparative is always weak — stærri, betri, eldri take only the small weak endings (masc./fem. -ri, neuter -ra: stærra, betra, eldra) regardless of position. The superlative declines fully — strong when indefinite, weak when definite — just like an ordinary adjective: stór bíll → stærsti bíllinn ("a big car → the biggest car"), where stærstur surfaces as the weak stærsti after the definite article.
Þetta er stærsta húsið í götunni.
This is the biggest house on the street. Superlative 'stærsta' — weak, because the phrase is definite ('the').
Hann keypti stærri bíl en hann þurfti.
He bought a bigger car than he needed. Comparative 'stærri' — weak, as all comparatives are.
Why English speakers go wrong here
Two transfer errors dominate. The first is over-regularising — reaching for -ari/-astur on an adjective that should umlaut or suppletate: *gamlari, *góðari, *stórari. English speakers do this because their own irregulars (gooder, baddest) feel childish, so they assume the "adult" form is the regular one; in Icelandic it's the reverse — the regular ending on these words is the mistake. The second is getting the umlaut vowel wrong — writing *stórri (keeping the ó) instead of stærri, or *langri instead of lengri. The fix is to remember that the i-umlaut changes the vowel — you cannot keep the positive's vowel and just bolt on -ri. Both errors disappear once you treat these adjectives as memorised chains, exactly as you'd memorise góður → betri → bestur.
Common Mistakes
❌ Afi er gamlari en amma.
Incorrect — 'gamall' is suppletive: the comparative is 'eldri', never the regularised '*gamlari'.
✅ Afi er eldri en amma.
Grandpa is older than Grandma. Comparative 'eldri'.
❌ Þessi bók er góðari en hin.
Incorrect — 'góður' is suppletive: comparative 'betri', not '*góðari'.
✅ Þessi bók er betri en hin.
This book is better than the other. Comparative 'betri'.
❌ Reykjavík er stórri en Selfoss.
Incorrect — the comparative umlauts the vowel: 'stærri' (ó → æ), not '*stórri' with the positive's vowel kept.
✅ Reykjavík er stærri en Selfoss.
Reykjavík is bigger than Selfoss. Comparative 'stærri'.
❌ Þetta er versta veðrið — wait: 'Veðrið er vondara í dag.'
Incorrect — 'vondur/illur' is suppletive: the comparative is 'verri' (neuter 'verra'), not '*vondara'.
✅ Veðrið er verra í dag.
The weather is worse today. Comparative 'verra'.
❌ Hann er ungari en ég.
Incorrect — 'ungur' umlauts: comparative 'yngri' (u → y), not the regularised '*ungari'.
✅ Hann er yngri en ég.
He's younger than me. Comparative 'yngri'.
Key Takeaways
- The most common adjectives compare irregularly — you meet them immediately, so learn them early.
- The i-umlaut group keeps regular endings -ri / -stur but changes the stem vowel: stór → stærri → stærstur (ó → æ), hár → hærri → hæstur (á → æ), langur → lengri → lengstur (a → e), ungur → yngri → yngstur (u → y).
- These vowel changes are the same i-umlaut as the noun plurals (fótur → fætur, maður → menn) — learn the sound change once.
- The suppletive group swaps the stem and must be memorised as sets: góður → betri → bestur, vondur → verri → verstur, gamall → eldri → elstur, mikill → meiri → mestur, lítill → minni → minnstur.
- Endings behave normally: the comparative is always weak, the superlative declines fully (weak after 'the': stærsti bíllinn).
- Avoid the two transfer errors: don't over-regularise (*gamlari, *góðari) and don't keep the positive's vowel (*stórri for stærri).
Now practice Icelandic
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Icelandic →Related Topics
- Comparative and Superlative: Regular FormsA2 — Regular Icelandic comparison: comparative -ari (ríkur → ríkari, fallegur → fallegri) which ALWAYS takes weak endings, and superlative -astur (ríkastur) which declines fully (strong indefinite, weak definite: fallegasta húsið). Covers en 'than' and why Icelandic strongly prefers the synthetic suffix over a periphrastic meira/mest — the opposite of English's 'more/most' tendency.
- Comparison Syntax: en, sem, því ... þvíB1 — How comparisons are built in the clause, separate from comparative morphology: 'than' is en (no accent) with the standard usually in the SAME case as what it's compared to — hún er eldri en bróðir hennar; equality with eins ... og or jafn ... og; and proportional 'the more ... the more' with því ... því (því carries an accent). The case-matching after en is what disambiguates 'I like him more than her' from 'than she does'.
- Irregular and i-Umlaut PluralsB1 — The high-frequency nouns whose plural changes the stem vowel by old i-umlaut (fótur → fætur, bók → bækur, móðir → mæður) or by suppletion (maður → menn) — lexicalised forms you must memorise, but clustered by meaning (body parts, kinship, time words) and sharing a small set of vowel outcomes.
- I-Umlaut as a Sound AlternationB1 — I-umlaut (i-hljóðvarp) is an older fronting alternation frozen into Icelandic paradigms: a lost i or j in the next syllable pulled the stem vowel forward — a→e, o→y, u→y, á/ó→æ, ú→ý, au→ey. It explains maður→menn, fótur→fætur, stór→stærri, ungur→yngri. Unlike u-umlaut it is no longer productive, so you memorise the affected sets — but the same alternation links surprising word-families.
- The Weak (Definite) DeclensionA2 — The full weak adjective paradigm — used after the definite article, demonstratives, and possessives — laid out for gamall, with its tiny inventory of -i and -a (and -u) endings, the rule that definiteness drives the choice, and the redundant double-marking (gamli maðurinn) that English speakers systematically under-produce.