In writing, at and og are two completely different words, but in everyday speech they collapse into nearly the same lazy sound — both reduce to something like a swallowed "o" or "å" — so the only place the difference actually surfaces is on the page, which is exactly where learners (and native Danes) get it wrong. The good news is that this is one of the most solvable errors in Danish: you can decide between them with a quick test in English.
The quick answer
Og means and — it links two equal things (two nouns, two verbs, two whole clauses). At is either the infinitive marker to (it stands in front of a verb's basic form: at gå, "to go") or the complementiser that (it introduces a reported clause: at han kommer, "that he is coming").
So the test is a translation test:
- Could you say "and" in the English version? → write og
- Could you say "to" (before a verb) or "that" (before a clause)? → write at
Because and, to, and that are three distinct words in English, your native ear has already done the sorting. You just have to trust it.
Og = "and" (joining two equals)
Og is a coordinating conjunction. It sits between two grammatically equal partners and welds them together. If you remove og, you'd have two things that could each stand on their own.
Jeg købte mælk og brød.
I bought milk and bread.
Hun synger og danser hele tiden.
She sings and dances all the time.
Vi spiste, og bagefter gik vi en tur.
We ate, and afterwards we went for a walk.
In all three, English uses and — milk and bread, sings and dances, we ate and afterwards. That is your signal for og, every time.
Notice the third example joins two full sentences (Vi spiste / bagefter gik vi en tur). That is still "and," and still og. The size of what you're joining doesn't matter — only that the two halves are equals.
At = "to" (the infinitive marker)
The second job of at is to mark an infinitive — the bare, unconjugated form of a verb. In English this is the little word to in to go, to eat, to understand. Danish puts at in exactly the same slot.
Det er svært at lære dansk.
It is hard to learn Danish.
Jeg har lyst til at rejse til Norge.
I feel like travelling to Norway.
Hun glemte at låse døren.
She forgot to lock the door.
Replace at with the English to in front of a verb and the sentence works: hard to learn, feel like to travel (in Danish), forgot to lock. That is at, the infinitive marker.
A useful sign: at of this kind is almost always followed by a verb in its dictionary form (lære, rejse, låse). If a bare verb comes right after, you are looking at "to," not "and."
At = "that" (the complementiser)
The third job of at is to introduce a reported clause — a chunk that reports what someone thinks, says, knows, or hopes. English uses that here (and often lets you drop it, which is why learners forget it exists).
Jeg tror, at det bliver regn i morgen.
I think (that) it will rain tomorrow.
Hun sagde, at hun var træt.
She said (that) she was tired.
Det er vigtigt, at du kommer til tiden.
It is important that you arrive on time.
In each case English allows that: I think that, she said that, important that. Even when English drops it ("I think it will rain"), the slot is still a "that"-slot — so Danish still wants at. A reliable sign: at of this kind is followed by a whole little clause with its own subject and conjugated verb (det bliver, hun var, du kommer).
Why this confusion exists (and why English speakers have an advantage)
Spoken Danish reduces unstressed function words aggressively. At is normally pronounced like a weak "å" (the t goes silent), and og is pronounced like "å" or "o" too — so by ear they are practically twins. Danish children make this same mistake for years; it is one of the classic markers of a hastily written text.
English speakers actually have a built-in edge here, because your language never merged these meanings. You would never confuse and with to with that — they sound nothing alike. So instead of trying to hear a difference that isn't there in Danish speech, translate the sentence in your head and let English keep the three concepts apart for you.
Classify these
Work through these the way a Dane proofreading their own text would — by asking "and, to, or that?"
- Jeg vil gerne _ sove nu. → "I'd like to sleep now." → at (at sove).
- Mor _ far er hjemme. → "Mum and dad are home." → og.
- Han lovede _ han ville hjælpe. → "He promised that he would help." → at.
- Vi skal handle ind _ lave mad. → "We're going to shop and cook." → og.
- Det er dejligt _ se dig igen. → "It's lovely to see you again." → at (at se).
- Hun håber, _ det går godt. → "She hopes that it goes well." → at.
- Kan du både synge _ spille guitar? → "Can you both sing and play guitar?" → og.
- Jeg glemte _ jeg havde et møde. → "I forgot that I had a meeting." → at.
Note number 8 versus Jeg glemte at ringe ("I forgot to call"): glemte at ringe takes "to" + verb, while glemte at jeg havde takes "that" + clause. Both are at — you don't even have to tell the two at-senses apart to spell it right. You only have to keep at separate from og.
Common Mistakes
These are real transfer and ear-driven errors. The fix is always the substitution test.
❌ Jeg håber og du kommer.
Incorrect — this is a 'that'-clause, so it needs at, not og.
✅ Jeg håber, at du kommer.
I hope (that) you come.
❌ Det er rart og se dig.
Incorrect — 'to see' needs the infinitive marker at.
✅ Det er rart at se dig.
It's nice to see you.
❌ Jeg købte kaffe at te.
Incorrect — 'coffee and tea' joins two equals, so it needs og.
✅ Jeg købte kaffe og te.
I bought coffee and tea.
❌ Hun begyndte og græde.
Incorrect — 'to cry' is an infinitive, so at, not og.
✅ Hun begyndte at græde.
She started to cry.
❌ Vi var trætte at sultne.
Incorrect — 'tired and hungry' joins two adjectives, so og.
✅ Vi var trætte og sultne.
We were tired and hungry.
The pattern in every wrong version: the writer reached for whichever spelling matched the sound, instead of asking which English word fits. Håber takes a "that"-clause → at. Rart … se is "to see" → at. Kaffe … te is "coffee and tea" → og.
Decision flowchart
| Ask in English… | If yes… | Write | Example |
|---|---|---|---|
| Does "and" fit? (joining two equals) | It's a conjunction | og | mælk og brød |
| Does "to" + verb fit? | It's the infinitive marker | at | at lære |
| Does "that" + clause fit? | It's the complementiser | at | at han kommer |
Key takeaways
- Og and at sound almost identical in speech but are never interchangeable in writing.
- Og = and, joining two equal elements.
- At = to (before a bare verb) or that (before a full clause). Both senses are spelled at.
- Don't trust your ear; translate to English and ask: and, to, or that?
- Mastering this single test instantly cleans up the most common error in written Danish — one that even native speakers stumble over.
Now practice Danish
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Start learning Danish→Related Topics
- Writing Og for At (and vice versa)A2 — Why Danes themselves mix up at and og in writing, and a one-second English test that always tells them apart.
- The Infinitive and the Marker AtA1 — The Danish infinitive, the infinitive marker at ('to'), when to use it and when to drop it — and the notorious at/og spelling trap.
- At (to) vs At (that)C1 — Danish has two words spelled at — the infinitive marker 'to' and the complementiser 'that'. A decision test plus the spoken og/at trap that catches even natives.
- Coordinating Conjunctions: Og, Men, Eller, For, SåA1 — The five Danish coordinators join clauses of equal rank without changing word order — plus the for vs fordi 'because' contrast and the og/at homophone trap.
- Uses of the InfinitiveB1 — Where the bare infinitive and the at-infinitive appear in Danish — after modals, after other verbs and prepositions, as subject or object, in for at / uden at / ved at, and as instructions on signs.
- At-clauses (Content Clauses)B1 — How Danish builds 'that'-clauses with at — their subordinate word order, when at can be dropped, and how to tell the complementiser at apart from the infinitive marker at and the conjunction og.