"Why did you do it?" and "What happened as a result?" are two of the most useful things to say in any language. Danish keeps purpose (the goal you act toward) and result (the consequence that follows) in tidy separate boxes, and the box you pick depends on one question: is the subject the same on both sides, or different? Get that question right and the rest falls into place. This page is a builder — work through the patterns, then assemble your own sentences from the substitution table.
Purpose: for at vs så (at)
To say you do something in order to achieve a goal, Danish gives you two tools, and the choice is mechanical.
Same subject → for at + infinitive
When the doer of the action and the doer of the goal are the same person, use for at + the infinitive (no new subject, no finite verb):
Jeg ringer for at høre, om du kommer.
I'm calling (in order) to hear whether you're coming.
Hun sparer op for at købe en lejlighed.
She's saving up (in order) to buy a flat.
Vi tog tidligt afsted for at undgå trafikken.
We left early to avoid the traffic.
In all three, one subject does both things: jeg calls and jeg hears; hun saves and hun buys. So no second subject is needed — just the bare infinitive after for at.
Different subject → så (at) + finite clause
When the goal involves a different subject — you act so that someone else can do something — you cannot use the infinitive (it has nowhere to put the new subject). Switch to så (at) + a full finite clause:
Jeg taler langsomt, så du kan forstå mig.
I'm speaking slowly so (that) you can understand me.
Jeg skriver det ned, så vi ikke glemmer det.
I'm writing it down so we don't forget it.
Hun tændte lyset, så børnene kunne se.
She turned on the light so the children could see.
The at after så is optional and usually dropped in speech: så du kan forstå and så at du kan forstå are both fine. After så (at), you have an ordinary subordinate clause: any sentence adverb like ikke sits before the verb (så vi *ikke glemmer det*).
Result: så ... at and derfor
Result looks backward at a consequence rather than forward at a goal.
så + adjective/adverb ... at — "so ... that"
To say something was so X that Y followed, wrap the quality in så ... at. The så sits right before the adjective or adverb; the at-clause states the consequence:
Det var så koldt, at vandet frøs til is.
It was so cold that the water froze to ice.
Han løb så hurtigt, at ingen kunne følge med.
He ran so fast that no one could keep up.
Filmen var så kedelig, at vi gik før tid.
The film was so boring that we left early.
The at here is not optional — you keep it: så koldt, *at vandet frøs. The comma before *at is standard (see the punctuation conventions).
derfor — "therefore" with inversion
For a result that stands as its own main clause, use the adverb derfor ("therefore, that's why"). Because Danish is a V2 language and derfor takes first position, the subject and verb invert: verb second, subject third.
Det regnede. Derfor blev vi hjemme.
It was raining. Therefore we stayed home.
Bussen var aflyst, og derfor kom jeg for sent.
The bus was cancelled, and that's why I was late.
Hun var syg, derfor tog hun ikke med.
She was ill, so she didn't come along.
Look closely at the order after derfor: Derfor *blev vi..., derfor **kom jeg..., derfor **tog hun...* — verb first, then subject. This is the same V2 logic that governs every fronted element in Danish.
Model sentences, graded
From simplest to most complex — say each one aloud:
Jeg går i seng for at sove.
I'm going to bed to sleep. (same subject, for at)
Hun læser højt, så barnet kan falde i søvn.
She reads aloud so the child can fall asleep. (different subject, så)
Vi mødtes tidligt for at nå toget.
We met early to catch the train. (same subject)
Tal lidt højere, så alle kan høre dig.
Speak a bit louder so everyone can hear you. (different subject)
Kaffen var så stærk, at jeg ikke kunne sove.
The coffee was so strong that I couldn't sleep. (result, så ... at)
Toget var forsinket, derfor missede jeg mødet.
The train was delayed, so I missed the meeting. (result, derfor + inversion)
Substitution table
Build your own sentences by mixing a left-column trigger with a matching right-column slot. Watch which structure each trigger demands.
| Trigger | What follows | Example slot |
|---|---|---|
| for at (same subject) |
| ... for at spare penge |
| for at (same subject) |
| ... for at lære dansk |
| så (at) (different subject) |
| ... så du kan nå det |
| så (at) (different subject) |
| ... så vi ikke glemmer det |
| så ... at (result) | adjective + at-clause | så træt, at jeg faldt i søvn |
| så ... at (result) | adverb + at-clause | så godt, at alle klappede |
| derfor (result) |
| derfor blev jeg hjemme |
| derfor (result) |
| derfor ringede hun ikke |
Jeg lærer dansk for at få et job i København.
I'm learning Danish to get a job in Copenhagen.
Skriv det på en seddel, så du ikke glemmer det.
Write it on a note so you don't forget it.
Common mistakes
Using for at + a finite clause when the subjects differ
This is the headline error. For at can only take an infinitive, so it cannot host a new subject. The moment the goal has a different subject, you must switch to så.
❌ Jeg taler langsomt for at du kan forstå mig.
Incorrect — for at can't take a new subject (du).
✅ Jeg taler langsomt, så du kan forstå mig.
I speak slowly so you can understand me.
Forgetting inversion after derfor
Derfor sits in first position, so V2 demands the verb next. Keeping English subject-verb order is the classic slip.
❌ Det regnede, derfor vi blev hjemme.
Incorrect — no inversion; verb must come before the subject.
✅ Det regnede, derfor blev vi hjemme.
It was raining, so we stayed home.
Dropping the at in så ... at
In the purpose sense, at after så is optional. In the result sense (så ... at = "so ... that"), the at is required — drop it and the sentence stalls.
❌ Det var så koldt, vandet frøs.
Incorrect — result så ... at needs the at.
✅ Det var så koldt, at vandet frøs.
It was so cold that the water froze.
Adding til on the model of English "to"
English "in order to" tempts learners to write for at til. Purpose is just for at + infinitive — no extra til.
❌ Hun ringer for at til at høre nyt.
Incorrect — no extra 'til'; for at + bare infinitive.
✅ Hun ringer for at høre nyt.
She's calling to hear the news.
Key takeaways
Now practice Danish
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Start learning Danish→Related Topics
- For at, Uden at, I stedet for atB1 — The Danish conjunctions that take an infinitive rather than a finite clause — for at (in order to), uden at, ved at, i stedet for at — and the same-subject rule that governs them.
- Causal and Result ConnectivesB1 — Danish words that mark cause and consequence — derfor, således, dermed, derved, af den grund — all adverbs that trigger V2 inversion, unlike the subordinator fordi.
- 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.
- Conditionals: Hvis-clauses and VilleB1 — Real and unreal conditional sentences in Danish — and why the language uses the plain past tense, not a special subjunctive, for hypothetical situations.
- Inversion After a Fronted ElementA1 — Whenever a non-subject opens a Danish main clause — an adverb, object, prepositional phrase, or subordinate clause — the verb stays second and the subject moves behind it.