Once you understand aspect, the practical question is how to make the perfective form. For the large productive classes, the imperfective stem is the present stem (γράφ-, αγαπ-) and a regular operation derives the perfective. That stem feeds the aorist (έγραψα), simple future (θα γράψω), perfective subjunctive (να γράψω) and perfective imperative (γράψε). Suppletive and one-stem verbs are exceptions to this assembly rule.
The core operation: add -σ-
The productive regular pattern builds the perfective stem by adding -σ- (sigma) to the present stem. Its surface shape follows two questions:
- Does a linking vowel go in first? — the line between the two conjugation classes.
- What happens where the -σ- lands on a consonant? — the merges, handled on their own page.
Answer those and the whole system falls out.
Class Α: stem + -σ-
In the productive Class Α pattern — verbs stressed on the stem (λύνω, γράφω, ακούω) — sigma attaches straight to the stem, with no linking vowel.
Where the stem ends in a vowel (or a nasal -ν- that simply drops), the join is clean:
| Present | Perfective stem | Aorist (1sg) | Meaning |
|---|---|---|---|
| λύνω | λύσ- | έλυσα | untie, solve |
| ακούω | ακούσ- | άκουσα | hear |
| κλείνω | κλείσ- | έκλεισα | close |
Δώσε μου ένα λεπτό να λύσω αυτό το πρόβλημα και έρχομαι.
dhóse mu éna leptó na líso aftó to próvlima ke érchome
Give me a minute to solve this problem and I'll come. (perfective subjunctive on λύσ-)
Θα ακούσω το τραγούδι σου μόλις γυρίσω σπίτι.
tha akúso to traghúdhi su mólis yiríso spíti
I'll listen to your song as soon as I get home. (simple future on ακούσ-)
Where the stem ends in a consonant, the -σ- fuses with it into ψ, ξ or σ (γράφ- → γράψ-, τρέχ- → τρέξ-, διαβάζ- → διάβασ-). Those merges are the whole subject of perfective consonant changes — this page sends you there and moves on.
The -εύω sub-family: -εψ-
A large, tidy pocket of Class Α is the verbs in -εύω. The historical labial in that ending surfaces before the -σ- as -εψ-:
| Present | Perfective stem | Aorist (1sg) | Meaning |
|---|---|---|---|
| δουλεύω | δουλέψ- | δούλεψα | work |
| χορεύω | χορέψ- | χόρεψα | dance |
| ταξιδεύω | ταξιδέψ- | ταξίδεψα | travel |
| μαγειρεύω | μαγειρέψ- | μαγείρεψα | cook |
Δούλεψα όλη μέρα και δεν πρόλαβα ούτε να φάω.
dhúlepsa óli méra ke dhen prólava úte na fáo
I worked all day and didn't even get to eat.
Χόρεψα μέχρι το πρωί στο γλέντι του χωριού.
chórepsa méchri to proí sto ghléndi tu choriú
I danced until morning at the village feast.
Αν έρθεις το Σάββατο, θα σου μαγειρέψω μουσακά.
an érthis to Sávato, tha su mayirépso musaká
If you come on Saturday, I'll cook you moussaka.
Class Β: linking vowel + -σ-
Regular Class Β verbs have stressed present endings (αγαπώ, μιλώ, μπορώ). Their perfective series places -σ- after a lexical linking vowel. That vowel comes in three main patterns, and which one a verb takes must be learned with the verb.
The tables use contracted presents in -ώ. For wavering verbs, forms such as μιλάω / μιλώ and ρωτάω / ρωτώ are both real current Greek and lead to the same perfective stems μιλήσ- and ρωτήσ-.
The -ήσ- family (the default, and by far the largest)
Most Class Β verbs take -ησ-. When in doubt, this is the safe bet:
| Present | Perfective stem | Aorist (1sg) | Meaning |
|---|---|---|---|
| αγαπώ | αγαπήσ- | αγάπησα | love |
| μιλώ | μιλήσ- | μίλησα | speak |
| ρωτώ | ρωτήσ- | ρώτησα | ask |
| κρατώ | κρατήσ- | κράτησα | hold, keep |
| οδηγώ | οδηγήσ- | οδήγησα | drive |
Τον αγάπησα από την πρώτη κιόλας στιγμή.
ton aghápisa apó tin próti kyólas stighmí
I loved him from the very first moment.
Πρέπει να μιλήσω με τον γιατρό πριν αποφασίσω.
prépi na milíso me ton yatró prin apofasíso
I need to speak to the doctor before I decide.
Τον ρώτησα την ώρα και μου την είπε ευγενικά.
ton rótisa tin óra ke mu tin ípe evyeniká
I asked him the time and he told me politely.
The -ασ- family
A smaller group takes -ασ-:
| Present | Perfective stem | Aorist (1sg) | Meaning |
|---|---|---|---|
| γελώ | γελάσ- | γέλασα | laugh |
| διψώ | διψάσ- | δίψασα | be thirsty |
| πεινώ | πεινάσ- | πείνασα | be hungry |
| χαλώ | χαλάσ- | χάλασα | break, ruin |
Γέλασα τόσο πολύ που πόνεσε η κοιλιά μου.
yélasa tóso polí pu pónese i kiliá mu
I laughed so hard my belly hurt.
The -εσ- family
A third, still smaller group takes -εσ- — and it includes two verbs you meet on day one, μπορώ and φορώ:
| Present | Perfective stem | Aorist (1sg) | Meaning |
|---|---|---|---|
| μπορώ | μπορέσ- | μπόρεσα | can, be able |
| φορώ | φορέσ- | φόρεσα | wear, put on |
| καλώ | καλέσ- | κάλεσα | call, invite |
Δεν μπόρεσα να κοιμηθώ καθόλου χθες το βράδυ.
dhen bóresa na kimithó kathólu chthes to vrádhi
I couldn't sleep at all last night.
Φόρεσα το καλό μου κοστούμι για τον γάμο.
fóresa to kaló mu kostúmi ya ton ghámo
I put on my good suit for the wedding.
Why this one stem is worth the trouble
The perfective stem is not just for the past. Build it once and it powers four different forms — you only change what leans on it:
| Form | Recipe | Example (μιλήσ-) |
|---|---|---|
| Aorist | stem + past endings (augment where required) | μίλησα — I spoke |
| Simple future | θα + stem + present endings | θα μιλήσω — I'll speak (bounded) |
| Perfective subjunctive | να + stem + present endings | να μιλήσω — to speak (bounded) |
| Perfective imperative | stem + imperative ending | μίλησε — speak! |
Θέλω να σου μιλήσω, να με πάρεις όταν μπορέσεις.
thélo na su milíso, na me páris ótan borésis
I want to talk to you — call me when you can. (perfective να on two stems)
The aorist endings that attach here are the subject of Aorist: Class Α; the futures and subjunctives that reuse the stem are covered in their own sections. What matters on this page is that they all draw from the one stem you just built.
Common Mistakes
1. Building a Class Β perfective without the linking vowel. μιλώ cannot go straight to ×μιλσω; the vowel is obligatory.
❌ Πρέπει να σε ρωτσω κάτι σημαντικό.
Incorrect — ρωτάω is Class Β and needs a linking vowel: ρωτήσω.
✅ Πρέπει να σε ρωτήσω κάτι σημαντικό.
prépi na se rotíso káti simandikó
I need to ask you something important.
2. Using the wrong linking-vowel family. αγαπώ takes -ησ-, not inline ×αγαπάσω; μπορώ takes -εσ-, not ×μπορήσω.
✅ Δεν μπόρεσα να έρθω στο πάρτι σου.
dhen bóresa na értho sto párti su
I couldn't come to your party.
3. Treating an -εύω verb like a Class Β verb. δουλεύω is Class Α; its perfective is δουλέψ-, not inline ×δουλεύησ-.
✅ Δούλεψα δέκα χρόνια σε εκείνη την εταιρεία.
dhúlepsa dhéka chrónia se ekíni tin etería
I worked ten years at that company.
4. Treating θα ακούω as a malformed perfective. It is a real imperfective future; use θα ακούσω when you instead frame the listening as bounded.
✅ Αύριο θα ακούω προσεκτικά όσο μιλάει.
ávrio tha akúo prosektiká óso milái
Tomorrow I'll be listening carefully while he speaks. (internal view)
✅ Αύριο θα ακούσω το μήνυμά του και θα αποφασίσω.
ávrio tha akúso to mínimá tu ke tha apofasíso
Tomorrow I'll listen to his message and decide. (bounded task)
Key Takeaways
- The productive regular pattern builds the perfective stem with -σ-; suppletive and one-stem verbs sit outside this derivation.
- Regular Class Α adds -σ- directly to the stem (λύσ-, ακούσ-); the -εύω sub-family gives -εψ- (δουλέψ-, χορέψ-); consonant-final stems merge — see the consonant-changes page.
- Productive Class Β patterns use a linking vowel: -ησ- (the default: αγαπήσ-, μιλήσ-), -ασ- (γελάσ-, διψάσ-), or -εσ- (μπορέσ-, φορέσ-). The vowel is unpredictable — learn it per verb.
- This one stem feeds the aorist, simple future, perfective subjunctive and perfective imperative — build it once, use it four ways.
- “Perfective” means a bounded viewpoint, not necessarily one objectively completed event; a finite repeated series can use the same stem.
Now practice Greek
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Start learning Greek →Related Topics
- The Two Verb StemsA2 — Aspect becomes visible through stem choice. Most productive verbs contrast an imperfective stem with a perfective stem—γράφω → γράψ-, αγαπώ → αγαπήσ-, παίζω → παίξ-—while one-stem and suppletive verbs require separate principal-part notes.
- Perfective Consonant ChangesB1 — When the perfective -σ- lands on a consonant, the two fuse: labials (π, β, φ) give ψ, velars (κ, γ, χ) give ξ, and dentals plus most sibilants give plain σ. Learn the three merges by stem-final sound and you can read and build the aorist, the simple future and the perfective subjunctive of almost any verb — plus the honest -ζω split (παίζω → παίξω but διαβάζω → διάβασα).
- Aorist: Class ΑA2 — The aorist of first-conjugation (Class Α) verbs — έγραψα, έγραψες, έγραψε, γράψαμε, γράψατε, έγραψαν — built from the augment, the perfective stem, and past endings that are identical to the imperfect's. The single insight: only the stem changes (γραψ- for the aorist, γράφ- for the imperfect); everything else is the same.