The Dutch teens end in -tien and the tens end in -tig — so once you know the units, you can almost build them yourself. Almost. A handful of forms bend the stem (dertien, veertien, dertig, veertig) and one is a genuine trap: tachtig (80) does not start with acht- the way you'd expect. This page lays out both rows, isolates exactly which forms are irregular, and drills the 13-vs-30, 14-vs-40 contrast that wrecks dictations.
The teens: -tien (13–19)
From 13 to 19, Dutch attaches -tien to a unit stem. Two of them change the stem; the rest are regular.
| Number | Dutch | Built from | Regular? |
|---|---|---|---|
| 13 | dertien | drie → der- | IRREGULAR (not 'drietien') |
| 14 | veertien | vier → veer- | IRREGULAR (not 'viertien') |
| 15 | vijftien | vijf + tien | regular |
| 16 | zestien | zes + tien | regular |
| 17 | zeventien | zeven + tien | regular |
| 18 | achttien | acht + tien | regular (double t: acht+tien) |
| 19 | negentien | negen + tien | regular |
Only dertien and veertien rearrange their stem. Drie loses its shape and becomes der-; vier shortens to veer-. The rest are just unit + tien. Note achttien keeps both t's (acht + tien), which is correct even though it looks doubled.
Mijn dochter wordt in maart dertien.
My daughter turns thirteen in March.
De bus van kwart over zeven was veertien minuten te laat.
The 7:15 bus was fourteen minutes late.
Ze hebben zestien jaar in Utrecht gewoond.
They lived in Utrecht for sixteen years.
The tens: -tig (20–90)
The tens end in -tig. Most are unit + tig, but the same two stems bend again (dertig, veertig), and tachtig is its own irregular beast.
| Number | Dutch | Built from | Regular? |
|---|---|---|---|
| 20 | twintig | (special form of twee) | irregular stem 'twin-' |
| 30 | dertig | drie → der- | IRREGULAR (not 'drietig') |
| 40 | veertig | vier → veer- | IRREGULAR (not 'viertig') |
| 50 | vijftig | vijf + tig | regular |
| 60 | zestig | zes + tig | regular |
| 70 | zeventig | zeven + tig | regular |
| 80 | tachtig | acht → tacht- | IRREGULAR (not 'achttig') |
| 90 | negentig | negen + tig | regular |
So the irregular tens are twintig (20), dertig (30), veertig (40), and tachtig (80). The first three you've half-met already (the der-/veer- stems and the special twin-). Tachtig is the one to flag with a highlighter.
Ze fietst nog elke dag, en ze is al tachtig.
She still cycles every day, and she's eighty already.
De maximumsnelheid is hier dertig kilometer per uur.
The speed limit here is thirty kilometres an hour.
Het kostte ruim veertig euro per persoon.
It cost well over forty euros per person.
The tachtig trap
Eighty is tachtig — and notice what's missing and what's added:
- It starts with t- that isn't in acht at all: t
- acht
- ig → tachtig.
- acht
- It has no -en- and no doubled consonant. It is not achttig, achtig, or achtentig.
Why the extra t-? Historically it comes from an old prefix (related to a Germanic counting form), and there's no modern rule that regenerates it — you simply memorise that 80 is tachtig. There is no logical shortcut here; tachtig and zeventig/negentig don't pattern together, so don't expect acht- to behave like zeven- and negen-.
Mijn oma is vorige maand tachtig geworden.
My grandmother turned eighty last month.
In de jaren tachtig was alles anders.
In the eighties everything was different. (decade names use the tens form)
The 13/30 and 14/40 contrast
This is where listening and spelling go wrong. The teen and the ten share the same bent stem, and differ only in the ending (-tien vs -tig) and the stress.
| Teen (-tien) | Ten (-tig) | Difference |
|---|---|---|
| dertien (13) | dertig (30) | ending + stress |
| veertien (14) | veertig (40) | ending + stress |
| vijftien (15) | vijftig (50) | ending only |
| zestien (16) | zestig (60) | ending only |
In careful speech the teens stress the -tien while the tens stress the first syllable: der-TIEN vs *DER-tig, veer-*TIEN vs *VEER-tig*. When someone says a price or a year quickly, that stress is often your only clue, so train your ear on the pairs directly.
Bedoel je dertien of dertig euro?
Do you mean thirteen or thirty euros? (the classic clarification question)
Niet veertien uur — veertig minuten.
Not fourteen hours — forty minutes.
For English speakers this contrast feels familiar — English has the very same problem with thirteen vs thirty, fourteen vs forty. The difference is that English resolves it almost entirely by stress (thir-TEEN vs *THIR-ty), whereas Dutch also changes the *ending sound clearly: -tien ends in a nasal -n, -tig ends in the throaty -ch sound. So in Dutch you have two cues, not one — listen for whether the word ends in -n (teen) or in the g/ch sound (ten), and the stress confirms it.
Why the tens don't take -en-
A small but useful point: the tens (twintig, dertig, … negentig) are plain unit + -tig, with no en in the middle. The en you may have seen — as in eenentwintig (21) or achtentachtig (88) — only appears when you add a unit in front of the ten. The bare ten itself never carries it. So 80 is tachtig, but 88 is achtentachtig (acht + en + tachtig). Keeping these apart stops the common over-correction of writing achtentig for 80.
Mijn buurman is achtentachtig en nog kerngezond.
My neighbour is eighty-eight and still in perfect health. (88 = acht-en-tachtig)
Zij is precies dertig, niet eenendertig.
She's exactly thirty, not thirty-one. (bare ten 'dertig' vs '+ unit' eenendertig)
Common Mistakes
❌ drietien / drietig
Incorrect — 'drie' bends to 'der-': dertien (13), dertig (30).
✅ dertien / dertig
thirteen / thirty
❌ viertien / viertig
Incorrect — 'vier' bends to 'veer-': veertien (14), veertig (40).
✅ veertien / veertig
fourteen / forty
❌ achttig
Incorrect — eighty is 'tachtig', with an added t- at the front and no doubling.
✅ tachtig
eighty
❌ De film duurt veertig minuten. (meaning 14)
Wrong number — 'veertig' is 40; fourteen is 'veertien'.
✅ De film duurt veertien minuten.
The film lasts fourteen minutes.
❌ achtentig
Incorrect — there's no '-en-' in 80; the ten is simply 'tachtig'. (88 is achtentachtig.)
✅ tachtig
eighty
Key Takeaways
- Teens take -tien, tens take -tig; most are just unit + ending.
- Irregular stems: dertien/dertig (drie → der-) and veertien/veertig (vier → veer-). Never drietien, viertig.
- tachtig (80) is the big trap: it adds a t- (t+acht+ig), has no -en-, and is never achttig.
- twintig (20) uses a special stem twin-.
- The 13/30, 14/40 pairs differ by ending and by stress (teens stress -tien, tens stress the first syllable) — the source of most mishearings.
Now practice Dutch
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