The ending -us presents an action or state as imagined rather than asserted as real. It often appears in counterfactual conditions—Se mi havus tempon, mi venus—and in polite requests such as Ĉu vi povus helpi? Unlike -as, -is, and -os, -us does not itself locate the situation in present, past, or future time.
All unlabelled uses below are neutral standard Esperanto. Polite -us works in both conversation and formal interaction; unusually dense compound forms are labeled where relevant.
Form: one ending for every subject
Remove infinitive -i and add -us: paroli → parolus, veni → venus, esti → estus. The form never changes for person or number.
| Subject | paroli | esti |
|---|---|---|
| mi | mi parolus | mi estus |
| vi | vi parolus | vi estus |
| li/ŝi/ĝi | li parolus | li estus |
| ni | ni parolus | ni estus |
| ili | ili parolus | ili estus |
Mi restus pli longe, sed la lasta trajno baldaŭ foriros.
I would stay longer, but the last train will leave soon.
Ili aĉetus la apartamenton, se ĝi havus balkonon.
They would buy the apartment if it had a balcony.
The subject and the verb's complements behave normally. A transitive -us verb still marks its object with -n: Mi aĉetus la apartamenton. Mood changes how the event is presented, not the verb's valency.
Counterfactual conditions
In a counterfactual se sentence, the speaker presents the condition as contrary to fact, unlikely, or deliberately hypothetical. Both the condition and its imagined result commonly use -us.
Se mi estus riĉa, mi laborus malpli.
If I were rich, I would work less.
Se ŝi scius la respondon, ŝi tuj dirus ĝin al ni.
If she knew the answer, she would tell us immediately.
This balanced se ... -us, ... -us pattern is productive, but se itself does not automatically require -us. Use real tense forms when the condition is open or presented as possible.
Se morgaŭ pluvos, ni nuligos la ekskurson.
If it rains tomorrow, we will cancel the excursion.
Se morgaŭ pluvus, ni devus nuligi la tutan ekskurson.
If it were to rain tomorrow, we would have to cancel the whole excursion.
The first speaker treats rain as a real future possibility and uses -os. The second steps back into a more hypothetical scenario and uses -us. The distinction is semantic; there is no mechanical rule that every clause after se must have one particular ending.
-US has no tense of its own
A simple -us form can refer to an imagined situation at any time. Time adverbs and context usually do the work.
Hieraŭ mi ne farus tiun eraron, se vi pli frue avertus min.
Yesterday I would not have made that mistake if you had warned me earlier.
Venontjare mi studus eksterlande, se mi ricevus stipendion.
Next year I would study abroad if I received a scholarship.
The first sentence is about an unreal past; the second is about a hypothetical future. Both use simple -us forms because -us expresses unreality, not a time coordinate.
When explicit anteriority is essential, Esperanto can use estus + active past participle: estus veninta “would have come.” This is fully grammatical but heavier than a simple -us form with a clear time expression.
Se ni estus ekveturintaj pli frue, ni ne estus maltrafintaj la trajnon.
If we had set off earlier, we would not have missed the train.
Simple -us remains possible when context already places the imagined event in the past, as in Hieraŭ mi ne farus tiun eraron, se... Speakers often choose the compound when explicit anteriority prevents ambiguity. Do not, however, build a compound merely because English has would have: simple -us is frequently enough.
Polite distance: povus, volus, devus
Imagining a request rather than imposing it directly creates social distance. This makes povus and bonvolus common polite forms.
Ĉu vi povus sendi al mi la fakturon hodiaŭ?
Could you send me the invoice today?
Ĉu vi bonvolus paroli iom pli malrapide?
Would you kindly speak a little more slowly?
The ability or willingness may be perfectly real. -Us presents it as a hypothetical possibility, allowing the listener room to respond. This is ordinary politeness, not doubt about whether the person exists or can act.
Volus often corresponds to “would like,” while devus commonly expresses advice or an unmet expectation rather than a literal imagined duty.
Mi volus rezervi tablon por kvar personoj.
I would like to reserve a table for four people.
Vi devus sekurkopii la dosierojn antaŭ la ĝisdatigo.
You should back up the files before the update.
La buso devus jam esti ĉi tie; eble ĝi malfruas.
The bus should already be here; perhaps it is late.
The second devus expresses recommendation; the third expresses an expectation that reality may not satisfy. These are established extensions of the imagined-mode meaning.
-US versus -U
-Us imagines; -u presents an action as wanted, requested, ordered, or aimed at. Compare a hypothetical action with an exhortation.
Ni iru nun, antaŭ ol komenciĝos la pluvo.
Let's go now, before the rain starts.
Ni irus nun, se la aŭto estus preta.
We would go now if the car were ready.
Iru is volitive: the speaker proposes action. Irus is conditional: the action belongs to an imagined situation. Neither ending is a future tense, although both often concern actions later than the moment of speaking.
Similarly, Venu morgaŭ! requests a visit, while Vi venus morgaŭ, se la trajnoj funkcius imagines one. The volitive in -u gives the full command and subordinate-clause system.
English “would” that is not -US
English uses would for future viewed from a past reporting point. Esperanto normally keeps the future -os because the coming remains later than the reported speech.
Ŝi diris, ke ŝi venos vendrede.
She said that she would come on Friday.
Venus would suggest an imagined or conditional arrival. If the meaning is “was about to/intended to come,” estis venonta can make that past viewpoint explicit.
English also uses would for repeated past behavior. Esperanto uses -is with a frequency expression, not -us.
Kiam ni estis infanoj, ni ofte ludis apud la rivero.
When we were children, we would often play by the river.
The events are asserted as real past habits, so ludis is the right form. Translating the English auxiliary one word at a time would incorrectly make them imaginary.
Do not build the conditional with esti + infinitive
Esperanto finite endings attach directly to the lexical verb: irus, legus, aĉetus. Estus iri is not an English-style “would go,” and estus aĉeti is not “would buy.” Esti appears only when it contributes its own linking/existential meaning or heads a genuine participial compound.
Sen via helpo mi ne sukcesus fini la raporton ĝustatempe.
Without your help I would not manage to finish the report on time.
The conditional ending belongs on sukcesus. The infinitive fini remains an infinitive because it complements sukcesi.
Common Mistakes
Using -US in every se-clause
❌ Se la vendejo estos malfermita, mi aĉetus lakton.
Incorrect for an open future condition — the result is presented as real, not imagined.
✅ Se la vendejo estos malfermita, mi aĉetos lakton.
If the shop is open, I'll buy milk.
Treating -US as a future tense
❌ Mi vizitus vin morgaŭ, kaj tio estas mia firma plano.
Incorrect — -us makes the visit hypothetical, contradicting the firm-plan reading.
✅ Mi vizitos vin morgaŭ; ĉio jam estas aranĝita.
I will visit you tomorrow; everything is already arranged.
Copying English future-in-the-past
❌ Li promesis, ke li venus je la sesa.
Incorrect for a straightforward reported promise — venus makes the arrival conditional.
✅ Li promesis, ke li venos je la sesa.
He promised that he would come at six.
Using esti as a conditional auxiliary
❌ Mi estus iri kun vi, se mi havus tempon.
Incorrect — attach -us directly to iri.
✅ Mi irus kun vi, se mi havus tempon.
I would go with you if I had time.
Adding person endings
❌ Ili venusoj pli frue, se ili povus.
Incorrect — -us is complete and invariant; no plural ending follows it.
✅ Ili venus pli frue, se ili povus.
They would come earlier if they could.
Key Takeaways
- -Us marks imagined or counterfactual situations, not a tense.
- Se can introduce real or imagined conditions; choose the verb form by meaning.
- Simple -us can refer to past, present, or future; participial compounds add explicit temporal layering when needed.
- Povus, volus, and devus commonly soften requests, wishes, advice, and expectations.
- English future-in-the-past and habitual would normally use -os and -is, not -us.
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Start learning Esperanto →Related Topics
- The Volitive in -UB1 — Learn how invariant -u expresses commands, requests, wishes, proposals, purposes, and desired actions in subordinate clauses.
- No Person or Number AgreementB1 — Learn why every Esperanto verb ending remains unchanged across subjects and where person and number are expressed instead.
- Polite Requests with -USA1 — Learn how povus, bonvolus, volus, and impersonal -us forms create polite distance in Esperanto requests and service encounters.
- Condition Clauses with SeB1 — Form open and real conditions with se, choosing each clause’s tense independently and distinguishing conditions from embedded questions.
- Counterfactual ConditionalsB1 — Express imagined, unlikely, and contrary-to-fact conditions with se and -us, including clear present, future, past, and mixed-time patterns.