Scii: To Know Facts | Esperanto Grammar

Scii is the regular verb for possessing information: knowing a fact, an answer, whether something is true, how something works, or how to perform an action. It contrasts with koni, which presents familiarity or acquaintance with a person, place, work, or other identifiable entity. English uses “know” for both, so the complement—not the English translation—must guide the choice.

Complete regular paradigm

Form	Function	Typical translation
scii	infinitive	to know, to know how
scias	present indicative	know(s)
sciis	past indicative	knew
scios	future indicative	will know
scius	conditional	would know
sciu	volitive	know!, be aware!, let ... know

Mi scias la respondon, sed mi volas aŭdi vian opinion unue.

I know the answer, but I want to hear your opinion first.

Neniu sciis, ke la pordo aŭtomate ŝlosiĝas.

Nobody knew that the door locks automatically.

The verb never changes for person or number: mi scias, ŝi scias, ili scias. Sciu is most natural in expressions that call attention to information: Sciu, ke mi ne forgesis “Know/be aware that I have not forgotten.” It is less common than ordinary informative mi diru al vi....

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If the answer to “What is known?” is a fact, answer, clause, or method, choose scii. If it is a person, place, book, or other entity encountered through experience, first test koni.

Knowing a fact or answer

When the information is packaged as a noun phrase, scii is transitive and the object normally takes accusative -n.

Ĉu vi scias la pasvorton de la sendrata reto por gastoj?

Do you know the password for the guest Wi-Fi network?

Mi ne sciis lian novan adreson, do mi telefonis al lia frato.

I didn't know his new address, so I called his brother.

Ŝi scias ĉiujn regulojn, sed ŝi ankoraŭ faras erarojn sub premo.

She knows all the rules, but she still makes mistakes under pressure.

The object is informational: a password, address, rule, name, date, reason, or result. Knowing the words of a poem or song can likewise be scii la tekston parkere “know the text by heart.”

The object can be omitted when the missing information is obvious.

— Je kioma horo ili alvenos? — Mi ne scias; ili ankoraŭ ne respondis.

— What time will they arrive? — I don't know; they haven't replied yet.

This short Mi ne scias is neutral and extremely frequent in conversation.

Scii, ke... for known propositions

A ke-clause presents a complete proposition as the content of knowledge.

Ni scias, ke la unua solvo ne funkcios longtempe.

We know that the first solution will not work in the long term.

Mi jam sciis, ke vi elektos la bluan jakon.

I already knew that you would choose the blue jacket.

Sciu, ke vi ĉiam povas peti helpon.

Know that you can always ask for help.

The subordinate tense expresses the actual time relation. Esperanto does not change it merely because sciis is past. In mi sciis, ke vi elektos, future elektos locates the choice after the knowing. If the fact remains current, present is natural: Mi sciis, ke ŝi loĝas en Bruselo “I knew that she lives in Brussels.”

Do not replace scii with koni before a ke-clause. Koni selects an entity directly; scii selects propositional information.

Scii, ĉu... for yes-or-no information

Use ĉu when what is unknown is whether a proposition is true.

Ĉu vi scias, ĉu la apoteko estas ankoraŭ malfermita?

Do you know whether the pharmacy is still open?

Mi ne scias, ĉu mi povos fini la raporton hodiaŭ.

I don't know whether I'll be able to finish the report today.

The first ĉu asks the listener a direct question. The second introduces the embedded yes-or-no issue. English often uses “if” here, but Esperanto uses interrogative ĉu, not conditional se.

Ni scios morgaŭ, ĉu la propono estis akceptita.

We'll know tomorrow whether the proposal was accepted.

Use se only for a genuine condition: Se la propono estos akceptita, ni festos “If the proposal is accepted, we will celebrate.”

Scii with a ki- question word

An embedded content question begins with the same ki- word that would introduce the corresponding direct question.

Ĉu vi scias, kie mi povas ŝargi mian telefonon?

Do you know where I can charge my phone?

Neniu sciis, kial la trajno haltis inter la stacioj.

Nobody knew why the train stopped between stations.

Mi volas scii, kiu ŝanĝis la dosieron kaj kiam.

I want to know who changed the file and when.

Use kie, kiam, kial, kiel, kiu, kio, kiom, and related forms according to their role inside the embedded question. Do not add ĉu before an existing ki- word: mi ne scias, kie..., not ĉu kie.... See embedded questions with ki-correlatives.

Knowing how to do something

An infinitive can name an acquired procedure or skill known by the subject.

Mia avino scias fari videovokon pli bone ol mi.

My grandmother knows how to make a video call better than I do.

Ĉu vi scias naĝi? — Jes, sed mi ne scias plonĝi.

Do you know how to swim? — Yes, but I don't know how to dive.

Scii + infinitive and the compound scipovi + infinitive overlap. Scipovi explicitly combines knowledge and ability and is especially clear for a learned practical skill.

Li scipovas ripari biciklojn, sed hodiaŭ li ne povas veni.

He knows how to repair bicycles, but today he cannot come.

This sentence separates competence from current possibility. Scipovas ripari says he has the skill; ne povas veni says circumstances prevent his coming today. English “can” can hide that distinction.

Scii pri and the boundary with koni

Scii pri io means possess information about it, often without claiming direct familiarity.

Mi sciis pri la nova kafejo, sed mi ankoraŭ ne konis ĝin.

I knew about the new café, but I wasn't familiar with it yet.

Conversely, someone can know a person while not knowing a fact about them:

Mi bone konas Lucian, sed mi ne sciis, ke ŝi verkas poezion.

I know Lucia well, but I didn't know that she writes poetry.

This is the core contrast: scii concerns information; koni concerns familiarity or recognition. The boundary can depend on viewpoint. Scii la regulojn treats the rules as information learned; koni la regularon can present familiarity with a body of regulations as a whole.

Participles and productive derivatives

Because scii is transitive, both active and passive participles are possible.

Time relation	Active	Passive
ongoing	scianta — knowing	sciata — known
earlier/completed	sciinta — having known	sciita — learned/known earlier
later/intended	scionta — going to know	sciota — to be learned

Sciata is by far the most useful passive form, often in estas sciate, ke... or bone sciata fakto. The future and perfect passive forms are grammatical but uncommon because speakers usually choose ekscii, sciigi, or a finite clause.

Estas vaste sciate, ke regula dormo helpas la memoron.

It is widely known that regular sleep helps memory.

Important family members include:

ekscii — come to know, find out
sciigi — cause someone to know, inform or notify
scipovi — know how, possess a practical skill
scio — knowledge or an item of knowledge
nescia — not knowing, ignorant or unaware
scivoli — want to know, be curious

Kiam mi eksciis pri la nuligo, mi tuj sciigis la aliajn partoprenantojn.

When I found out about the cancellation, I immediately informed the other participants.

Bonvolu sciigi al mi la finan decidon antaŭ vendredo.

Please let me know the final decision before Friday.

Two common sciigi frames are sciigi iun pri io and sciigi al iu ion. Both keep the roles explicit; avoid placing two unmarked accusative objects together.

Register and frequency

Scii is extremely frequent and neutral in every register. Estas sciate, ke... is more characteristic of (formal), academic, or journalistic prose than casual conversation, where oni scias, ke... is lighter. Scipovi is neutral and useful when practical competence matters; esti kapabla emphasizes capacity rather than acquired knowledge.

The root sci- and its verbal paradigm are foundational; sciigi is likewise present in the foundational word family. The information-versus-acquaintance contrast with koni is normative, while borderline noun objects can reflect how the speaker frames the knowledge. This page's recommendation is to use an explicit clause whenever a compact noun might obscure that distinction.

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Use ekscii for the transition from not knowing to knowing, sciigi for causing another person to know, and scii/scipovi + infinitive for know-how.

Common Mistakes

Using koni before a proposition

❌ Mi konas, ke la vendejo fermas je la sesa.

Incorrect — a known proposition requires scii.

✅ Mi scias, ke la vendejo fermas je la sesa.

I know that the shop closes at six.

Using scii for acquaintance with a person

❌ Ĉu vi scias la novan instruiston?

Incorrect for being acquainted with the teacher.

✅ Ĉu vi konas la novan instruiston?

Do you know the new teacher?

Replacing embedded ĉu with conditional se

❌ Mi ne scias, se la muzeo estas malfermita.

Incorrect — this is an embedded yes-or-no question, not a condition.

✅ Mi ne scias, ĉu la muzeo estas malfermita.

I don't know whether the museum is open.

Combining ĉu with a ki- question word

❌ Ĉu vi scias, ĉu kie troviĝas la haltejo?

Incorrect — kie already marks the embedded content question.

✅ Ĉu vi scias, kie troviĝas la haltejo?

Do you know where the stop is?

Adding a preposition before a skill infinitive

❌ Ŝi scias kiel al uzi la programon.

Incorrect — use either scias uzi or scias, kiel uzi, without al.

✅ Ŝi scias uzi la programon.

She knows how to use the program.

Key Takeaways

Scii selects information: a factual object, a ke-clause, an embedded ĉu question, or a ki- question.
Koni selects a person, place, work, or other entity known through familiarity.
Scii/scipovi + infinitive expresses know-how; povi alone can instead express present ability, permission, or circumstances.
Ekscii means come to know, while sciigi means cause someone else to know.
All forms follow the regular root-plus-ending system.

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