The ending -os presents an action or state as expected after the relevant present. It corresponds to many English constructions with “will,” “be going to,” or a present form used for future time. Esperanto does not need an auxiliary: the future meaning is built directly into the verb.
Building the future
Replace infinitive -i with -os. The form stays identical with every subject.
| Infinitive | Future | Examples with subjects |
|---|---|---|
| paroli | parolos | mi parolos, ili parolos |
| veni | venos | ŝi venos, ni venos |
| esti | estos | vi estos, ĝi estos |
| havi | havos | li havos, ili havos |
Morgaŭ mi laboros hejme.
Tomorrow I will work from home.
Post la renovigo la ĉambro estos multe pli hela.
After the renovation the room will be much brighter.
Ĉu vi havos tempon por kafo post la kunveno?
Will you have time for coffee after the meeting?
Negation and questions do not require an English-style auxiliary. Put ne before the verb and use ĉu for a yes/no question.
Mi ne forgesos sendi al vi la adreson.
I won't forget to send you the address.
Prediction, intention, and promise
The future ending itself locates the situation after now. Context tells whether the sentence is a prediction, an intention, a promise, or a neutral statement about a schedule.
Laŭ la prognozo, posttagmeze pluvos.
According to the forecast, it will rain this afternoon.
Mi telefonos al la hotelo kaj demandos pri libera ĉambro.
I'll call the hotel and ask about an available room.
Ne zorgu; mi ne rakontos tion al iu ajn.
Don't worry; I won't tell that to anyone.
English may choose “will” for a spontaneous decision and “going to” for a prior plan. Esperanto -os can express both. If the distinction matters, lexical expressions make it explicit: mi intencas telefoni “I intend to call,” mi planas vojaĝi “I plan to travel,” or mi tuj faros tion “I will do that immediately.”
Eble ni venos iom malfrue pro la trafiko.
We may arrive a little late because of the traffic.
Mi certe finos la tradukon antaŭ vendredo.
I will certainly finish the translation before Friday.
The future is inherently not yet realized, but choosing -os presents the event as part of the speaker's view of what will occur. It does not guarantee the outcome.
Future states, duration, and repetition
Future -os works equally with events and states. A future situation may be momentary, extended, or habitual.
Venontjare ni loĝos en pli granda apartamento.
Next year we will live in a larger apartment.
Mi restos en Prago tri semajnojn.
I will stay in Prague for three weeks.
Dum la somero la muzeo estos malfermita ankaŭ lunde.
During the summer the museum will also be open on Mondays.
The duration tri semajnojn does not change the future form. Esperanto tense locates the overall situation; other expressions describe its duration, frequency, or internal shape.
Esperanto keeps future tense in subordinate clauses
English often uses a present form after “when,” “after,” “as soon as,” and “if,” even though the event is future: “when she arrives.” Esperanto normally marks the actual future time with -os.
Kiam ŝi alvenos, ni kune vespermanĝos.
When she arrives, we will have dinner together.
Mi sendos la dokumenton tuj kiam mi ricevos la subskribon.
I will send the document as soon as I receive the signature.
Post kiam la pluvo ĉesos, ni daŭrigos la ekskurson.
After the rain stops, we will continue the excursion.
Both events are future, so both verbs use -os. This is one of the strongest English-to-Esperanto transfer traps.
Realistic future conditions also use real tense forms, usually -os in the result and either -os or an appropriate factual form in the condition according to meaning.
Se morgaŭ pluvos, ni restos hejme.
If it rains tomorrow, we will stay home.
Se ŝi jam havas la ŝlosilon, ŝi povos eniri sen ni.
If she already has the key, she will be able to enter without us.
In the first, the rain is future; in the second, possession of the key is a present fact that may or may not hold. Do not automatically use -us after se. -us presents a condition as imagined or counterfactual, while -os presents a genuinely possible future occurrence.
Marked planned-future -as
In informal usage, one may encounter present -as for a fixed arrangement or timetable when a future-time phrase removes ambiguity. Foundational Esperanto nevertheless uses -os for an event that has not begun, so -os is the safest model for clear international prose.
Morgaŭ mi flugas al Lisbono.
Tomorrow I'm flying to Lisbon. (marked planned-present usage)
Morgaŭ mi flugos al Lisbono.
Tomorrow I will fly to Lisbon. (neutral future statement)
The -as version presents the event as part of a settled plan, but it is a marked extension found in usage. The -os version directly follows the core tense system and is the pedagogical default. See planned future with the present for the stylistic range.
Future from a past viewpoint
In indirect speech, Esperanto preserves the tense of the original message instead of changing it to an English-style “future in the past.”
Lina diris: ‘Mi revenos lunde.’
Lina said: ‘I will return on Monday.’
Lina diris, ke ŝi revenos lunde.
Lina said that she would return on Monday.
The -os in revenos is future relative to Lina's original statement. English changes “will” to “would”; Esperanto retains the original future form. Time words may need adjustment if the reporting context changes, but the verb ending does not backshift mechanically.
Outside genuine reported speech, a past narrative may express a later event with contextual devices or a participial construction. Do not assume every English “would” translates as -us: English “would” may be a past form of “will,” whereas Esperanto -us marks imagination or conditionality.
Future statement versus command
A sentence in -os predicts or asserts a future action. A direct request or command uses -u.
Vi fermos la pordon poste.
You will close the door later. (future statement)
Fermu la pordon, mi petas.
Close the door, please. (request)
Intonation can make “You will do this now!” sound commanding in many languages, and Esperanto speakers can exploit the same pragmatic force. Grammatically, however, -os remains future indicative; -u is the clear neutral choice for a command.
Common Mistakes
Building the future with esti plus an infinitive
❌ Mi estos vojaĝi morgaŭ.
Incorrect — future meaning belongs directly on the lexical verb.
✅ Mi vojaĝos morgaŭ.
I will travel tomorrow.
Copying English present tense after kiam
❌ Mi telefonos al vi, kiam mi alvenas.
Incorrect for a future arrival — Esperanto marks both future events.
✅ Mi telefonos al vi, kiam mi alvenos.
I will call you when I arrive.
Using -us for every open condition
❌ Se la vendejo estos malfermita, ni aĉetus panon.
Incorrect for a real future plan — the result is expected, not imagined as contrary to fact.
✅ Se la vendejo estos malfermita, ni aĉetos panon.
If the shop is open, we will buy bread.
Translating reported “would” with -us
❌ Ŝi diris, ke ŝi venus je la oka.
Incorrect if her original statement was a factual 'Mi venos je la oka.'
✅ Ŝi diris, ke ŝi venos je la oka.
She said that she would come at eight.
Using -os as the neutral command form
❌ Vi atendos ĉi tie!
Incorrect as a neutral request — -os states or predicts a future action.
✅ Atendu ĉi tie, mi petas.
Wait here, please.
Key Takeaways
- -os is the invariant future form for actions and states expected after the relevant present.
- It can express predictions, intentions, promises, future habits, and future states; context distinguishes them.
- Future-time and condition clauses normally keep -os where English often uses a present form.
- Planned-future -as is a marked, context-dependent extension; -os is the neutral future choice.
- In indirect speech, reported future stays -os; hypothetical -us and volitive -u have different functions.
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Start learning Esperanto →Related Topics
- Esperanto Verbs: The Complete SystemA1 — See how six invariant endings express infinitive, tense, conditionality, and volition without person or number conjugation.
- Planned Future with the PresentB1 — Recognize marked colloquial present forms for future arrangements while using standard future -os accurately and idiomatically.
- Tense in Subordinate ClausesB1 — Choose each subordinate verb from its own time and mood meaning rather than copying English tense patterns or mechanically matching the main verb.
- Relative Time without Sequence-of-Tense BackshiftA2 — Preserve the original verb form in reported speech and thought instead of applying English-style tense backshift.