This page is about one of the most reliable rules in Swedish spelling — and one small but stubborn exception to it. The rule: a doubled consonant tells you the vowel right before it is short. Once you trust it, you can read vowel length straight off the page and spell new words correctly by ear. This is the orthographic side of the length contrast covered in Long and Short Vowels; here we focus on when you write one consonant and when you write two.
The core rule: doubling marks a short stressed vowel
In a stressed syllable, Swedish length is a seesaw: the syllable has either a long vowel + short consonant (written with a single consonant letter) or a short vowel + long consonant (written with a doubled consonant). The spelling reflects this directly:
- One consonant letter after the stressed vowel → the vowel is long: vit (white), glas (a glass), kam (comb), väg (road).
- A doubled consonant after the stressed vowel → the vowel is short: vitt (white, neuter), glass (ice cream), kall (cold), vägg (wall).
The doubled letter is not decorative and it does not mean "say it louder." It is the orthography's way of writing "the vowel here is short." That is why so many minimal pairs differ by exactly one consonant letter.
| Long vowel (single consonant) | Short vowel (doubled consonant) |
|---|---|
| vit (white) | vitt (white, neuter) |
| glas (a glass tumbler) | glass (ice cream) |
| kal (bare) | kall (cold) |
| vila (to rest) | villa (detached house) |
Tröjan är vit, men byxorna är vitt tyg.
The sweater is white, but the trousers are white fabric. — vit (long i, single t) → neuter vitt (short i, double t).
Jag dricker ur ett glas och äter en glass.
I drink from a glass and eat an ice cream. — glas (long a, single s) vs glass (short a, double s).
Det är kallt ute, ta på dig något.
It's cold out, put something on. — kall has short a (double l); the neuter kallt keeps both l's, see below.
Why å, ä, ö behave exactly like a, e, o
The new vowel letters obey the doubling rule with no special treatment. A short å, ä, ö triggers a doubled consonant just like a short a, e, o would:
- mätt (full, after eating) has a short ä — doubled t — against mät (measure!) with a long ä.
- mött (met, past participle) has a short ö — doubled t — against möt (meet!) with a long ö.
- sätt (way, manner) has a short ä — doubled t — against sät… (no single-t counterpart here, but the short reading is fixed by the tt).
Maten var god och nu är jag mätt.
The food was good and now I'm full. — mätt: short ä, doubled t.
Kan du mäta bordet åt mig?
Can you measure the table for me? — mäta: long ä, single t.
Vi har inte mötts på länge.
We haven't met in a long time. — mötts: short ö, doubled t.
Simplification: when the doubling drops out
The doubled consonant does not survive everywhere. Two situations make a double consonant simplify to a single one, and both follow from the same logic: the doubling is only needed to mark a short vowel in a stressed syllable, so when that environment changes, the second letter is no longer required.
1. Before another consonant in an inflected form. When you add an ending that begins with a consonant — especially the verb supine/past -t or -de — a stem-final double consonant is often reduced to one, because the following consonant already guarantees the vowel is short. The classic case is känna (to feel/know):
- känna (infinitive) — double n
- känner (present) — double n
- but känt (supine), kände (past) — single n: the t/d after it does the job of marking the short ä.
Jag känner honom väl.
I know him well. — känner: double n (no following consonant to lean on).
Jag har känt honom i flera år.
I've known him for several years. — känt: single n, because the t already signals the short vowel.
2. It does not drop where the cluster already exists in the base. Be careful: kall → neuter kallt keeps both l's. Here the ll is part of the adjective stem and the added -t simply attaches; the doubling stays. Compare this with the känna → känt case, where the simplification is a fixed property of those verb forms. There is genuine irregularity here, so the safe move is to learn the inflected forms of high-frequency words individually.
Det blir kallt i natt.
It'll be cold tonight. — kallt: the stem kall keeps both l's; the neuter -t is added on top.
Hon ställde glaset på bordet.
She put the glass on the table. — ställde keeps the double l of ställa before -de.
The exception that trips up everyone: final m and n
This is the distinguishing point of the page, the one even advanced learners get wrong: at the end of a word, m and n are written single even after a short, stressed vowel — contradicting the general doubling rule. So you write hem with one m, not *hemm, and man with one n, not *mann, even though the vowel in each is short.
- Final -m stays single after a short vowel: hem (home), kom (came), ram (frame), dam (lady), rum (room), program (programme).
- Final -n stays single after a short vowel: man (one / man), men (but), vän (friend), kan (can), han (he), mun (mouth), igen (again).
But — and this is what makes it a true exception rather than a general short-vowel-doesn't-double rule — inside a word, between vowels, m and n double normally. So komma (to come) has mm, kamma (to comb) has mm, sommar (summer) has mm; kvinna (woman) has nn, vinna (to win) has nn, spänna (to stretch) has nn. The single letter is purely a word-final convention.
| Final position (single) | Medial position (doubled) |
|---|---|
| hem (home) | hemma (at home) |
| kom (came) | komma (to come) |
| kam (comb) | kamma (to comb) |
| vän (friend) | vänner (friends) |
| man (one / man) | manna (manna) |
The practical consequence is striking: a word's spelling can change as you inflect it. Hem gains a second m the moment a vowel follows — hem → hemma, hemmet; kom → komma. You are not adding a random letter; you are restoring the normal medial doubling that the word-final position had suppressed.
Jag vill gå hem, jag är hemma om en timme.
I want to go home; I'll be home in an hour. — hem (final, single m) but hemma (medial, double mm).
Kom hit och hjälp mig att komma in.
Come here and help me get in. — kom (final, single m) but komma (medial, double mm).
Han är en bra vän, och hans vänner är trevliga.
He's a good friend, and his friends are nice. — vän (final, single n) but vänner (medial, double nn).
A small set of words even uses the doubled final form on purpose to stay distinct from a single-m word: damm (dust / pond / dam) vs dam (lady), lamm (lamb) vs lam (lame). These are the rare cases where a final mm is written — precisely to break a homograph. For the full set of m/n sub-rules, see The m and n Rules.
En dam torkade bort dammet.
A lady wiped away the dust. — dam (lady, single m) vs damm (dust, double m); the doubling keeps them apart.
Vi såg ett litet lamm på gården.
We saw a little lamb in the yard. — lamm (lamb) is written with mm to distinguish it from lam (lame).
Common Mistakes
❌ komm — writing 'come' with a final double m, by analogy with komma
Incorrect — final -m is single even after a short vowel: kom. The mm only appears medially (komma).
✅ kom
came / come! (imperative)
❌ menn / vänn — doubling final n after a short vowel
Incorrect — final -n is single: men, vän. The nn returns only between vowels: vänner.
✅ men, vän
but / friend
❌ vit and vitt read with the same long i
Incorrect — the doubled t in vitt marks a short i: vit (long) vs vitt (short). The doubling is a length signal, not loudness.
✅ vit = long i; vitt = short i
white / white (neuter)
❌ känt written as 'kännt' with a double n
Incorrect — the n simplifies before t in this form: känna → känt. The following t already marks the short vowel.
✅ känt
felt / known (supine)
❌ kallt written 'kalt' with a single l
Incorrect — here the doubling does NOT simplify: the stem kall keeps both l's and -t is added: kallt. Don't over-apply the känt rule.
✅ kallt
cold (neuter)
Key Takeaways
- A doubled consonant marks a short, stressed vowel before it; a single consonant marks a long one (vit/vitt, glas/glass, kal/kall). The doubling is a length signal, not loudness.
- å, ä, ö follow the rule like any vowel: mätt, mött, sätt all have short vowels because of the doubled consonant.
- Doubling can simplify before an added consonant (känna → känt, kände) — but not when the cluster belongs to the stem (kall → kallt keeps ll). Learn high-frequency inflected forms individually.
- The big exception: final m and n are written single even after a short vowel (hem, kom, man, vän), but double medially (hemma, komma, vänner). A handful of words double final mm to avoid homographs (damm vs dam, lamm vs lam).
- See The m and n Rules for the full sub-rules and Long and Short Vowels for the pronunciation side.
Now practice Swedish
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Swedish→Related Topics
- Long and Short VowelsA1 — Swedish length is reciprocal: a stressed syllable has EITHER a long vowel + short consonant (väg, glas) OR a short vowel + long/doubled consonant (vägg, glass) — never both. The doubled consonant marks the short vowel, and the contrast distinguishes words.
- Swedish Spelling: OverviewA2 — Swedish spelling is fairly regular and largely phonemic — but you must master double consonants for vowel length, the soft/hard g and k, the many spellings of the sje-sound, and the iron rule that compounds are written as ONE word, since splitting them (särskrivning) is the most stigmatised error in the language.
- Spelling m and nB1 — Swedish doubles a consonant to mark a short stressed vowel — but m and n break this rule at the end of a word and write single (hem, kam, man, kom), restoring the double only when an ending follows (hemma, kamma, mannen, komma). Knowing the rule is positional turns 'kom but komma' from an exception into the system working.