Esperanto commonly marks a measure of time with -n: Mi atendis du horojn means “I waited for two hours.” This is not a direct object. The phrase measures the extent of the waiting, answering “how long?” rather than “what did I wait for?”
The basic duration pattern
A time noun or noun phrase takes -n when it directly measures the duration of an event. The construction works with moments, hours, days, years, and other units.
Mi atendis dudek minutojn, sed la buso ne venis.
I waited for twenty minutes, but the bus didn't come.
Ni restis ĉe niaj amikoj tri tagojn.
We stayed with our friends for three days.
La koncerto daŭris preskaŭ du horojn.
The concert lasted almost two hours.
— Ĉu vi povas atendi momenton? — Jes, sed ne longe.
— Can you wait a moment? — Yes, but not long.
English often uses “for,” though it can also omit it after verbs such as “wait.” Esperanto does not insert por simply because English has “for.” A bare duration measure normally takes -n.
The ending belongs to the whole agreeing phrase. A modifying adjective takes the same number and case endings as the noun.
Ŝi laboris la tutan nokton por fini la raporton.
She worked the whole night to finish the report.
Mi manĝis nenion varman la tutan tagon.
I didn't eat anything hot all day.
In la tutan nokton, both tuta and nokto carry -n. With a plural measure, -j precedes -n, as in tri longajn semajnojn.
La riparo daŭris tri longajn semajnojn.
The repair took three long weeks.
The equivalent dum-phrase
The preposition dum explicitly means “during/for the duration of.” Its complement does not take accusative marking, because an ordinary preposition already shows the phrase's role.
Ni parolis dum du horoj.
We talked for two hours.
Ni parolis du horojn.
We talked for two hours.
These sentences are close in meaning. The bare accusative is concise and extremely common; dum can make the temporal relation explicit or introduce a longer phrase. Do not combine the two strategies as dum du horojn.
Por has a different core meaning. With a period of time, it often presents an intended, allotted, or planned period rather than simply measuring how long the event in fact lasted.
Ŝi luis la apartamenton por ses monatoj, sed foriris post kvar.
She rented the apartment for six months, but left after four.
Ŝi efektive loĝis tie kvar monatojn.
She actually lived there for four months.
The first sentence states the contractual period; the second measures the realized stay. Context sometimes makes the distinction less important, but the contrast explains why por is not a universal translation of English “for.”
Duration, time point, and clock time
Duration answers “how long?” A calendar-time accusative answers “when?” These forms can look alike but have different functions.
Mi laboris unu tagon.
I worked for one day. (duration)
Mi laboris lundon.
I worked on Monday. (calendar time point)
With clock time, use je: je la tria means “at three o'clock.” Do not use la trian for this purpose in careful modern Esperanto, because the accusative is already used for calendar dates and measures and the unmarked clock reading would be needlessly ambiguous.
La kunveno komenciĝos je la tria kaj daŭros du horojn.
The meeting will begin at three and last for two hours.
The two phrases neatly display the contrast: je la tria locates the start; du horojn measures its duration. The calendar dates in the accusative page treats time-point -n separately.
Frequency and temporal distance
A measure accusative can say how many times an event occurs. Fojo is a countable noun, so it takes ordinary plural and accusative marking.
Mi kontrolas mian retpoŝton du fojojn tage.
I check my email twice a day.
Kiom da fojoj vi telefonis? — Tri fojojn, sed neniu respondis.
How many times did you call? — Three times, but no one answered.
The phrase can also measure a temporal gap relative to another point. In du tagojn poste, the accusative says how large the interval is; poste says on which side of the reference point the event falls.
Du tagojn poste, la pakaĵo finfine alvenis.
Two days later, the package finally arrived.
Ni renkontiĝis unu semajnon antaŭ la konferenco.
We met one week before the conference.
Do not say unu semajnon antaŭ and stop there if you mean “one week before something.” Here antaŭ is a preposition and requires its complement. If the reference point is already understood, use unu semajnon antaŭe.
Mi sendis la invitilojn vendrede, kaj ŝi jam telefonis unu tagon antaŭe.
I sent the invitations on Friday, and she had already called one day earlier.
Age, lateness, and other measured states
The same construction can measure a property expressed by an adjective or adverb. It is established to say tridek jarojn aĝa “thirty years old” and dek minutojn malfrue “ten minutes late.”
Mia frato estas tri jarojn pli juna ol mi.
My brother is three years younger than I am.
La trajno alvenis dek kvin minutojn malfrue.
The train arrived fifteen minutes late.
Kiam ŝi estis dudek jarojn aĝa, ŝi translokiĝis eksterlanden.
When she was twenty years old, she moved abroad.
This usage measures the degree of age, difference, or lateness. It still is not an object. When multiple n-marked phrases would make a sentence hard to parse, je can introduce the measure instead. Clarity takes priority over showing how many accusatives a sentence can grammatically contain.
When a time measure has no -n
A measure does not automatically take -n in every syntactic position. When it is the subject, it remains nominative. A predicative expression after esti also normally remains unmarked.
Tri tagoj pasis sen novaĵoj.
Three days passed without news.
La atendotempo estis preskaŭ du horoj.
The waiting time was almost two hours.
Compare La atendado daŭris du horojn: there the measure complements daŭri and receives -n. Esperanto case reflects the phrase's grammatical job, not merely the idea of time.
Common Mistakes
Copying English “for” as por
❌ Mi atendis por du horoj.
Incorrect for a simple factual duration — por suggests an intended or allotted period.
✅ Mi atendis du horojn.
I waited for two hours.
Adding -n after dum
❌ Ni babilis dum la tutan vesperon.
Incorrect — the preposition dum takes an unmarked complement.
✅ Ni babilis dum la tuta vespero.
We chatted throughout the whole evening.
Leaving an adjective unmarked
❌ Ili restis tutan semajnojn.
Incorrect — the adjective must agree in number as well as case.
✅ Ili restis tutajn semajnojn.
They stayed for whole weeks.
Marking a subject as a duration complement
❌ Du semajnojn pasis tre rapide.
Incorrect — two weeks is the subject of pasis.
✅ Du semajnoj pasis tre rapide.
Two weeks passed very quickly.
Using a duration for a clock time
❌ La filmo komenciĝos la sepan.
Incorrect in careful usage — clock time is introduced by je.
✅ La filmo komenciĝos je la sepa.
The film will begin at seven.
Key Takeaways
- A bare phrase answering “how long?” normally takes -n: Ni atendis du horojn.
- After dum, keep the complement unmarked; use por when an intended or allotted period is the point.
- Duration, calendar time, and clock time are distinct: unu tagon, lundon, and je la tria do different jobs.
- A time quantity used as a subject or predicative value remains unmarked.
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Start learning Esperanto →Related Topics
- Duration and FrequencyA2 — Express how long and how often events occur with measured accusatives, dum-phrases, recurring time expressions, and fojo-based forms.
- Calendar Dates in the AccusativeB1 — Learn why Esperanto calendar dates often take temporal -n, how to write ordinal dates, and when a date correctly remains unmarked.
- Measures and PriceA2 — Mark bare measures of weight, size, value, and price with -n while distinguishing them from objects and prepositional phrases.
- DumA2 — Use dum before a time expression or clause to place one event within the duration of another.
- JeB1 — Use je for conventional clock-time, measure, body-part, and abstract relations when no more specific preposition expresses the intended role.