oppdage (to discover) | Norwegian Grammar

oppdage ("to discover, to notice, to realise") is a prefixed verb, and that prefix is what makes it a B1 topic. Norwegian has many verbs built on the particle opp-, and most of them are separable — the particle can split off and move around the sentence. oppdage is one of the exceptions: its opp- is welded on for good. It never separates, it conjugates as a regular weak verb, and it covers a useful spread of English meanings from "discover" through "notice" to "realise."

Conjugation

Class: weak (-et / -et), prefixed and inseparable. Auxiliary: ha.

Tense / mood	Norwegian	English
Infinitiv	å oppdage	to discover
Presens	oppdager	discover(s), notice(s)
Preteritum	oppdaget	discovered
Perfektum	har oppdaget	have/has discovered
Pluskvamperfektum	hadde oppdaget	had discovered
Futurum	skal/vil oppdage	will discover
Imperativ	oppdag!	discover!
Presens partisipp	oppdagende	discovering (adjective)

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The verb inflects like a regular weak verb on its end: -et in both the preterite and the supine, so oppdaget covers "discovered" and "have discovered." It is never oppdagte. Crucially, the whole word inflects as a unit — you add the ending to oppdage, you do not touch the opp-.

The inseparable opp- prefix

Here is the point of the page. Norwegian draws a line between two kinds of opp- verbs:

Separable particle verbs, where opp is a free-standing adverb that detaches: å vaske opp → jeg vasker opp tallerkenene ("I wash up the plates"), and it can sit apart from the verb.
Inseparable prefixed verbs, where opp- is fused to the root and never moves: oppdage is one of these.

With oppdage, the opp- stays glued in every position. You say jeg oppdager, jeg oppdaget, jeg har oppdaget — the particle never floats to the end of the clause the way a separable one does. Writing it as two words (oppe dage, opp dage) or splitting it (jeg dager opp) is simply not Norwegian.

The stress falls on the prefix in the inseparable type: ÓPP-dage. (In the separable type, the stress sits on the particle too, but the particle is a separate word.) For your purposes the safe rule is mechanical: with oppdage, never break the word apart.

Vi oppdaget en liten kafé i en sidegate.

We discovered a little café in a side street.

Forskerne har oppdaget en helt ny planet.

The researchers have discovered a brand-new planet.

Jeg oppdaget for sent at jeg hadde glemt lommeboka.

I noticed too late that I'd forgotten my wallet.

oppdage at — realise that

A very common use is oppdage at ("realise/notice that") introducing a clause. Here oppdage means coming to be aware of a fact — often suddenly, often about something that was already the case without you knowing.

Plutselig oppdaget hun at hun hadde gått feil vei.

Suddenly she realised she'd gone the wrong way.

Da vi kom hjem, oppdaget vi at noen hadde vært innom.

When we got home, we discovered that someone had been by.

Han har nettopp oppdaget at billetten var ugyldig.

He's just realised that the ticket was invalid.

oppdage vs legge merke til — discover vs notice

These overlap but pull in different directions. oppdage is about coming upon something you didn't know was there — a discovery, a realisation, often with an element of surprise. legge merke til ("notice, pay attention to") is about your attention registering a detail that was perfectly findable all along; it is closer to plain "notice." You oppdager a leak you didn't know about; you legger merke til that your friend has a new haircut.

Jeg la merke til at du hadde klippet deg.

I noticed you'd had a haircut.

Først nå oppdager jeg hvor mye jeg har lært.

Only now do I realise how much I've learned.

The related noun is en oppdagelse ("a discovery"), built with the noun-forming suffix -else — as in en stor vitenskapelig oppdagelse ("a great scientific discovery").

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Quick split: if the thing was hidden or unknown and you came upon it (a fact, a place, a leak), use oppdage. If it was in plain sight and your attention simply caught it, use legge merke til.

Common Mistakes

❌ Jeg dager opp at noe var galt.

Incorrect — oppdage is inseparable; the opp- never splits off

✅ Jeg oppdaget at noe var galt.

I realised that something was wrong.

❌ Vi har oppdagt en feil i regnskapet.

Incorrect — the supine is oppdaget, with -et, not oppdagt

✅ Vi har oppdaget en feil i regnskapet.

We've discovered an error in the accounts.

❌ Jeg oppdaget en ny frisyre på vennen min.

Odd — for catching a visible detail, Norwegian uses legge merke til

✅ Jeg la merke til en ny frisyre på vennen min.

I noticed my friend's new hairstyle.

❌ Hun oppdaget om at toget var forsinket.

Incorrect — oppdage takes at (not om at) before a statement clause

✅ Hun oppdaget at toget var forsinket.

She noticed that the train was delayed.

Key Takeaways

oppdage / oppdager / oppdaget / har oppdaget / oppdag! — weak, both past forms oppdaget (never oppdagte or oppdagt).
The opp- prefix is inseparable: it never detaches and never moves. Stress on ÓPP-dage.
oppdage at
- clause = realise/notice that something is the case, often with surprise.
Contrast oppdage (come upon the unknown) with legge merke til (notice a visible detail).
The noun is en oppdagelse ("a discovery").

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