This is the er that English speakers find most alien — and the single biggest source of er errors. The rule behind it is short and absolute: in Dutch, a preposition cannot take an ordinary object pronoun for a thing. You can say met hem ("with him") and over haar ("about her") for people, but you cannot say met het or over het for things. To say "with it," "about it," "on it," Dutch replaces the thing-pronoun with er and fuses it onto the front of the preposition: er + mee = ermee ("with it"), er + op = erop ("on it"), er + over = erover ("about it"). Naming this ban — no preposition + thing-pronoun, ever — is what finally makes er feel mandatory instead of mysterious.
This page covers the fusion: how er + preposition forms a single word, and the parallel waar- and daar- words. The way that fused word splits apart in a real sentence (er ... over) is treated separately on Splitting Er from Its Preposition — read this page first.
The ban that drives everything
People keep their normal pronouns after a preposition: met hem, aan haar, over hen. Things cannot. The instant the object of a preposition is an inanimate "it" (or "them" for things), the pronoun is forbidden and er takes over, gluing itself to the preposition. So where English has a tidy "preposition + it," Dutch has a fused er-word.
| English | ❌ Impossible in Dutch | ✅ Fused er-word |
|---|---|---|
| with it | met het | ermee |
| about it | over het | erover |
| on it | op het | erop |
| of/about it | aan het | eraan |
| in it | in het | erin |
| to it | tot het | ertoe |
Three core examples
Many Dutch verbs come welded to a fixed preposition — denken aan (think about), klaar zijn met (be done with), praten over (talk about). When the thing after that preposition turns into "it," you build the er-word.
Ik denk er niet aan.
I'm not thinking about it. The verb is 'denken aan'; the thing-object becomes 'er ... aan'. You cannot say 'denken aan het'.
Ben je ermee klaar?
Are you done with it? 'Klaar zijn met' + a thing → 'ermee'. Not 'klaar met het'.
We hebben er lang over gepraat.
We talked about it for a long time. 'Praten over' + a thing → 'er ... over'. 'Over het' is impossible.
You'll notice two of these are already split (er ... aan, er ... over) rather than written solid (eraan, erover). That splitting is the normal sentence pattern and gets its own page; here, focus on why it's an er-word at all — because the preposition cannot take het.
The irregular fusions: met → mee, tot → toe
Two prepositions change shape when they fuse with er (or daar / waar / hier). You must memorise these — there is no logical reason, it's a frozen historical form:
- met ("with") becomes mee: er
- met → ermee (never ermet)
- tot ("to/until") becomes toe: er
- tot → ertoe (never ertot)
Ik ben er heel blij mee.
I'm very happy with it. 'Blij met' + a thing → 'er ... mee' (met → mee). 'Ermet' does not exist.
Het heeft er niets mee te maken.
It has nothing to do with it. 'Te maken hebben met' → 'er ... mee'; again met becomes mee.
Ze hebben hem ertoe gedwongen.
They forced him into it. 'Dwingen tot' + a thing → 'ertoe' (tot → toe).
Every other preposition keeps its shape: op stays op (erop), aan stays aan (eraan), over stays over (erover), in stays in (erin), van stays van (ervan). Only met and tot mutate.
The same rule for questions and relatives: waar- and daar-
The ban — no preposition + thing-pronoun — applies just as strictly when the "thing" is a question word or a relative. You cannot say met wat ("with what") or over wat ("about what") for things; you must use waar + preposition. And to point at a known thing emphatically, you use daar + preposition, the stressed counterpart of er.
| unstressed "it" | stressed "that" | question "what" | |
|---|---|---|---|
| about | erover | daarover | waarover |
| with | ermee | daarmee | waarmee |
| on | erop | daarop | waarop |
Waar denk je aan?
What are you thinking about? Not 'aan wat' — a preposition can't take 'wat' for a thing, so it's 'waar ... aan'.
— Waar denk je aan? — Ik denk eraan.
— What are you thinking about? — I'm thinking about it. The question uses 'waar ... aan', the answer 'er ... aan' — same construction, different element.
Dat is het boek waarmee ik begon.
That's the book I started with. The relative 'waarmee' (with which) is forced by the same ban; you can't say 'met dat' for a thing here.
The deep payoff: er-, daar-, waar- and hier- words are one family, generated by one ban. Er is the unstressed "it," daar the stressed "that," waar the question "what," hier the "this." Learn the ban once and all four columns follow. The question forms live on Prepositional Questions; the relative forms on Waar- Relative Clauses.
Common Mistakes
These are the highest-frequency er errors English speakers make — all the same mistake: using a preposition with het (or wat/dat) for a thing.
❌ Ik denk niet aan het.
Incorrect — a preposition cannot take 'het' for a thing. The thing-object must become 'er ... aan'.
✅ Ik denk er niet aan.
I'm not thinking about it.
❌ Ben je klaar met het?
Incorrect — 'met het' for a thing is impossible. Use the fused 'ermee' (met → mee).
✅ Ben je ermee klaar?
Are you done with it?
❌ We hebben over het gepraat.
Incorrect — 'over het' for a thing is banned. It must be 'er ... over'.
✅ We hebben erover gepraat.
We talked about it.
❌ Waarmet schrijf je?
Incorrect — 'met' fuses irregularly to 'mee'. The form is 'waarmee'.
✅ Waarmee schrijf je?
What are you writing with?
❌ Ik denk aan wat?
Incorrect — a preposition + 'wat' for a thing is impossible. Use 'waar ... aan'.
✅ Waar denk je aan?
What are you thinking about?
Key Takeaways
- The driving rule is a ban: a Dutch preposition cannot take a pronoun for a thing — no met het, over het, op het.
- Instead, er + preposition fuses into one word: ermee, erover, erop, eraan, erin, ertoe.
- Two irregular fusions to memorise: met → mee (ermee) and tot → toe (ertoe); all other prepositions keep their shape.
- The same ban produces the question words waar- (waarmee, waarover) and the stressed daar- (daarmee, daarover) — one family, one rule.
- This fused word usually splits in real sentences (er ... over); see Splitting Er from Its Preposition.
Now practice Dutch
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Start learning Dutch→Related Topics
- Er: The Five Uses OverviewA2 — A map of the notorious word er and its five distinct jobs — existential, locative, pronominal, quantitative and placeholder subject — that happen to share one spelling, with a route to the dedicated page for each.
- Splitting Er from Its PrepositionB2 — In real sentences the fused er-word breaks apart — er lands early in the middle field while the preposition floats near the verb cluster (Ik heb er gisteren met hem over gesproken); the Waar...over / Daar...over split is the normal spoken form.
- Locative Er (There = In That Place)B1 — Locative er is the unstressed pro-form for a place already mentioned — Ik werk er al jaren — while stressed, contrastive 'there' is daar; the er/daar split is the unstressed/stressed distinction that runs through the whole pronoun system.
- Compound Prepositions and CircumpositionsB2 — Dutch frames many spatial relations with two parts that bracket the noun — a preposition before and a postposition after: van de tafel af, naar het strand toe, om het huis heen, door de muur heen, tegen de wind in, uit een klein dorp vandaan. The wrapping adds directional or emphatic force English handles with a single word, and dropping the second part is the classic learner error.
- Asking with Prepositions: Waarop, Waarmee, Met wieB1 — How Dutch asks 'with what / about what / for what': for things, preposition + wat fuses into waar + preposition and usually splits (Waar wacht je op?); for persons, it stays preposition + wie (Met wie ga je?).
- Waar + Preposition: Relatives for ThingsB2 — How to build relative clauses for things after a preposition in Dutch using waar + preposition — fused (waarop) or split (waar … op) — and why you can never say 'op die' or 'met dat'.