English builds its perfect one way: have plus a past participle, for every verb without exception — I have eaten, I have come, she has gone. Icelandic builds it two ways, and choosing between them is the first thing you have to get right. Most verbs use hafa ("to have") plus the supine — ég hef borðað "I have eaten" — exactly mirroring English. But a large group of intransitive motion and change-of-state verbs use vera ("to be") instead — ég er kominn "I have come," hún er farin "she has gone" — and when you use vera, the participle stops being a frozen -ið form and agrees with the subject in gender and number, like an adjective. (This page is about choosing the auxiliary and making it agree; how the supine itself is built — -að / -t / -ið — lives on the supine and participle page, and the separate vera búinn að resultative is its own construction.)
The default: hafa + supine
For the overwhelming majority of verbs — all transitives and most intransitives — the perfect is hafa + supine, just like English have + participle. The supine is the fixed -ð/-t/-ið form; it does not change for the subject. So hafa conjugates for person, and the supine sits there inert:
| Person | hafa (present) |
| English |
|---|---|---|---|
| ég | hef | borðað | I have eaten |
| þú | hefur | borðað | you have eaten |
| hann/hún/það | hefur | borðað | he/she/it has eaten |
| við | höfum | borðað | we have eaten |
| þið | hafið | borðað | you (pl.) have eaten |
| þeir/þær/þau | hafa | borðað | they have eaten |
Notice the supine borðað is identical in every row — masculine, feminine, neuter, singular, plural. This is the easy case, and it's most of the language.
Við höfum lesið bókina tvisvar.
We've read the book twice. 'höfum lesið' — hafa-perfect, supine 'lesið' is invariant.
Hefur þú séð þessa mynd?
Have you seen this film? 'hefur ... séð' — supine 'séð' doesn't change for the subject.
Ég hef aldrei borðað hákarl.
I've never eaten fermented shark. 'hef borðað' — the everyday hafa-perfect.
Þau hafa búið í Reykjavík í tíu ár.
They've lived in Reykjavík for ten years. 'hafa búið' — hafa even with a stative verb.
The vera-perfect: motion and change of state
A specific group of intransitive verbs of motion and change of state takes vera instead. These are verbs where the subject moves or transforms — and the perfect describes the resulting state as much as the past event. The core members: koma "come," fara "go/leave," verða "become," byrja "begin," enda "end," hætta "stop," vakna "wake up," sofna "fall asleep," deyja "die." English uses have for all of these; Icelandic uses vera.
Ég er kominn.
I have come / I'm here now. 'er kominn' — vera-perfect of 'koma'; note the masculine participle.
Hún er farin heim.
She has gone home. 'er farin' — vera-perfect of 'fara'.
Strætó er ekki kominn enn.
The bus hasn't come yet. 'er ... kominn' — vera-perfect; the participle agrees with masculine 'strætó'.
The semantic logic is worth internalising, because it lets you predict the choice rather than memorise a list: hafa foregrounds the action (you did something — and the object, if any, takes the action), while vera foregrounds the resulting state of the subject (you are now in the place/condition the verb led to). Ég hef farið þangað oft ("I have gone there often" — repeated action, with hafa) but ég er farinn ("I'm gone / I've left" — current state, with vera). Many motion verbs can in fact take either, with this difference in meaning.
The participle AGREES in the vera-perfect
This is the part with no English parallel at all, and the part learners most often get wrong. In a hafa-perfect the supine is frozen (borðað). But in a vera-perfect, the form after vera is not the supine — it's the past participle, and like any predicate adjective after vera it agrees with the subject in gender and number. So "have come" is kominn / komin / komið depending on who came:
| Subject | "has come" (vera-perfect of koma) | "has gone" (vera-perfect of fara) |
|---|---|---|
| Masculine sg. (hann) | er kominn | er farinn |
| Feminine sg. (hún) | er komin | er farin |
| Neuter sg. (það) | er komið | er farið |
| Masculine pl. (þeir) | eru komnir | eru farnir |
| Feminine pl. (þær) | eru komnar | eru farnar |
| Neuter/mixed pl. (þau) | eru komin | eru farin |
Compare this directly with the flat hafa-perfect. Ég hef komið would keep the same komið for everyone; but ég er kominn / komin / komið changes with the speaker's gender. The perfect, in this construction, becomes an agreement task — exactly the same endings you already use for predicate adjectives (hann er þreyttur, hún er þreytt, þau eru þreytt).
Pabbi er kominn heim.
Dad has come home. Masculine 'kominn'.
Mamma er komin heim.
Mum has come home. Feminine 'komin' — one fewer -n than the masculine.
Gestirnir eru komnir.
The guests have arrived. Masculine plural 'komnir'.
Stelpurnar eru farnar í skólann.
The girls have gone to school. Feminine plural 'farnar'.
Börnin eru sofnuð.
The children have fallen asleep. Neuter plural 'sofnuð' (from 'sofna'), agreeing with neuter 'börn'.
The pluperfect: hafði / var + supine
To push the perfect one step further into the past — English's had eaten, had gone — simply put the auxiliary into the preterite. Hafa → hafði; vera → var. The supine or agreeing participle stays exactly as before. So hafa-verbs give ég hafði borðað ("I had eaten"), and vera-verbs give hún var farin ("she had gone"), with the participle still agreeing.
| Perfect (present aux.) | Pluperfect (past aux.) | |
|---|---|---|
| hafa-verb (borða) | ég hef borðað | ég hafði borðað |
| vera-verb (fara), fem. subj. | hún er farin | hún var farin |
Ég hafði borðað áður en gestirnir komu.
I had eaten before the guests came. Pluperfect 'hafði borðað' — past auxiliary.
Þegar ég kom heim var hún þegar farin.
When I got home she had already gone. Pluperfect 'var ... farin' — past 'var' + the agreeing feminine participle 'farin'.
English vs Icelandic, in one comparison
English collapses everything into have; Icelandic splits the work and adds agreement. The single sentence "She has gone" shows all three differences at once: Icelandic prefers vera (motion verb), so it's er not hefur; the form is a participle, not a supine; and that participle agrees with the feminine subject — farin. Where English writes one invariant gone, Icelandic chooses an auxiliary and inflects a participle. Once you stop translating have mechanically and start asking "is this a motion/change verb, and who is the subject?", the system becomes mechanical in a good way.
Common Mistakes
❌ Hún hefur farin heim.
Incorrect — two errors: 'fara' takes the vera-perfect, and after 'hefur' you'd need the supine 'farið', not the participle. Use 'er farin'.
✅ Hún er farin heim.
She has gone home. vera-perfect with the agreeing participle 'farin'.
❌ Hún er farinn.
Incorrect — the participle must agree with the FEMININE subject 'hún': 'farin', not the masculine 'farinn'.
✅ Hún er farin.
She has gone. Feminine 'farin'.
❌ Strákarnir er komið.
Incorrect — a masculine PLURAL subject needs plural 'eru' and the masculine plural participle 'komnir', not the neuter singular 'komið'.
✅ Strákarnir eru komnir.
The boys have arrived. Masculine plural 'komnir'.
❌ Ég hef borðaður allan matinn.
Incorrect — after 'hafa' the form is the invariant SUPINE 'borðað', never an agreeing participle. Agreement happens only in the vera-perfect.
✅ Ég hef borðað allan matinn.
I've eaten all the food. hafa-perfect, frozen supine 'borðað'.
❌ Þegar ég kom var hún þegar farinn.
Incorrect — even in the pluperfect the participle agrees with 'hún': feminine 'farin'.
✅ Þegar ég kom var hún þegar farin.
When I came she had already gone. Pluperfect 'var farin'.
Key Takeaways
- The perfect = auxiliary + supine/participle. Default auxiliary is hafa (ég hef borðað), exactly like English have.
- A group of intransitive motion / change-of-state verbs (koma, fara, verða, byrja, hætta, vakna, sofna, deyja) takes vera instead: ég er kominn, hún er farin.
- In the hafa-perfect the supine is frozen (borðað for everyone); in the vera-perfect the participle agrees with the subject in gender and number (kominn / komin / komið / komnir / komnar / komin).
- The semantic split: hafa foregrounds the action, vera the subject's resulting state — many motion verbs allow both with this difference.
- The pluperfect just uses the past auxiliary: hafði borðað, var farin — the participle still agrees.
- Treat the vera-perfect as an agreement task: ask "who is the subject?" before choosing the participle ending.
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- Supine vs Past ParticipleB1 — Two forms English collapses into one '-ed/-en'. The SUPINE is the frozen -að/-t/-ið form used after hafa in the perfect (ég hef borðað, ég hef tekið) — it never changes. The PAST PARTICIPLE is a fully declined adjective (borðaður/borðuð/borðað, tekinn/tekin/tekið) used in the passive and the vera-perfect, where it agrees with its subject in gender, number, and case. Getting the split wrong breaks both the perfect and the passive.
- vera búinn að: The Resultative 'Have Done'B1 — The everyday colloquial resultative vera búinn að + infinitive ('to have finished/already done'): ég er búinn að borða 'I've already eaten / I'm done eating'. búinn AGREES with the subject like an adjective (búinn/búin/búið), the following verb is a bare infinitive, and in speech this construction is far more common than the hafa-perfect for completed actions — over-relying on hef + supine sounds bookish.
- The Preterite (þátíð): UsesA2 — What the simple past tense does — the default narrative past that covers English simple past AND, often, the present perfect for completed events, with Icelandic's separate hafa + supine perfect used more selectively, and the German-style ban on the perfect with definite past-time adverbs (no *ég hef farið í gær).
- hafa (to have)A1 — The full conjugation of Icelandic hafa, 'to have' — present hef/hefur/hefur/höfum/hafið/hafa, past hafði/hafðir/hafði/höfðum/höfðuð/höfðu, supine haft — the language's main perfect auxiliary, with the u-umlaut in höfum/höfðum.
- vera (to be)A1 — The full conjugation of Icelandic's most frequent and most irregular verb — present er/ert/er/erum/eruð/eru, past var/varst/var/vorum/voruð/voru, subjunctive sé/væri, imperative vertu — plus its jobs as copula, perfect auxiliary, and passive auxiliary.
- verða vs vera: 'Be' and 'Become'B1 — Both touch on English 'be', but vera is the stative copula — being in a state — while verða is the verb of change, future, and necessity, covering 'become' (hann varð reiður), 'will be' (það verður gott veður á morgun), and 'have to' (ég verð að fara). The split usually comes down to one question: state (vera) or change/future (verða)? — and English's flat 'be' hides all three of verða's jobs at once.