Numerals are one of the few places where the shape of the writing — not just the words — differs sharply from English, and getting the shapes wrong makes a text read as visibly foreign. Finnish flips three of English's conventions at once: the decimal separator is a comma, thousands are grouped with a space, and dates run day-first. On top of that, Finnish has a small trick English lacks entirely — a colon that attaches a grammatical case ending directly to a digit. This page covers how numbers look on the page; how they are declined and pronounced is developed on Numbers and Dates and Fractions and Decimals.
Decimal comma, spaced thousands
Finnish and English use the opposite symbols here, so a single character can flip a number's meaning entirely.
| Meaning | English | Finnish |
|---|---|---|
| pi | 3.14 | 3,14 |
| one and a half | 1.5 | 1,5 |
| one million | 1,000,000 | 1 000 000 |
| twelve thousand five hundred | 12,500 | 12 500 |
The decimal separator is a comma; the thousands separator is a space (a thin, non-breaking space in careful typesetting). So English 1,000,000 — which a Finnish reader would try to read as a decimal — is written 1 000 000, and English 3.14 becomes 3,14.
Matka maksoi 1 250,50 euroa.
The trip cost 1,250.50 euros. — space groups the thousands, comma marks the decimal.
Piin arvo on noin 3,14.
The value of pi is about 3.14. — the decimal separator is a comma, never a point.
Currency and percent: symbol after, with a space
Where English writes €10 or $5, Finnish puts the symbol after the figure with a space: 10 €, 5,50 €. The percent sign likewise follows a space: 50 %, not 50%.
Kahvi maksaa 3,50 € ja pulla 2 €.
The coffee costs €3.50 and the bun €2. — the euro sign follows the number after a space.
Alennus on 50 % koko viikon.
The discount is 50% all week. — a space separates the number and the percent sign.
Dates: day first, each part with a period
Finnish dates run day.month.year, each element followed by a period, the reverse of American month/day/year. Finland's Independence Day is 6.12. — the sixth of December, not the twelfth of June.
| Date | Written | Read as |
|---|---|---|
| 6 Dec 2017 | 6.12.2017 | kuudes joulukuuta 2017 |
| 1 Jan | 1.1. | ensimmäinen tammikuuta |
| 24 Dec | 24.12. | kahdeskymmenesneljäs joulukuuta |
Itsenäisyyspäivää vietetään 6.12.
Independence Day is celebrated on the 6th of December. — day-first, and the period is part of the date.
Nähdään 3.5. kello kuusi.
See you on the 3rd of May at six. — 3.5. is the third of May, not the fifth of March.
Ordinals need a period
This is the mistake that changes a number's grammar, not just its style. Written as figures, ordinal numbers take a period: 3. is kolmas (third), 5. is viides (fifth). A bare 3 is the cardinal kolme (three). The period is what tells the reader "third," and dropping it is a real error, not a typo.
Asun 3. kerroksessa.
I live on the 3rd floor. — '3.' with a period is 'kolmas' (third); '3' alone would be 'three'.
Tämä on hänen 2. kirjansa.
This is her 2nd book. — the period makes '2.' the ordinal 'toinen' (second), not the cardinal 'two'.
When you need the ordinal to be unmistakable, you may also spell out its ending with a colon: 5:s = viides, 3:s = kolmas. The period form is the standard in running text; the colon-ordinal is a disambiguating alternative.
The colon: gluing a case ending onto a digit
Here is the feature English has nothing like. When a figure needs a case ending, Finnish attaches that ending straight to the digit with a colon. The digit is read as its number word, and the ending is the ordinary case suffix.
| Written | Read as | Meaning |
|---|---|---|
| 2:ssa | kahdessa | in two |
| klo 5:ltä | (kello) viideltä | at / from five o'clock |
| bussi 7:ään | (bussi) seitsemään | onto bus (number) 7 |
| 2010-luvulla | kaksituhattakymmenluvulla | in the 2010s |
Nousin bussi 7:ään keskustassa.
I got on bus 7 in the centre. — '7:ään' spells the illative ending onto the digit: seitsemään.
Soitan sinulle klo 5:ltä.
I'll call you from five o'clock. — 'klo' is 'kello'; '5:ltä' is 'viideltä'.
Hän syntyi 2010-luvulla.
She was born in the 2010s. — the decade word 'luku' is inflected and attached with a hyphen: 2010-luvulla.
The ending harmonises to the spoken number
The crucial subtlety: the suffix after the colon obeys vowel harmony according to how the number is read aloud, not how the digit looks. You cannot see the harmony in the figure — you have to hear the word.
- 5:ltä — read viideltä; viisi has only i, so it goes front: -ltä.
- 7:ään — read seitsemään; seitsemän contains ä, so it goes front: -ään.
- 6:sta — read kuudesta; kuusi has u, so it goes back: -sta.
Otin junan klo 6:sta ja vaihdoin klo 7:ään.
I took the 6 o'clock train and changed at 7. — 'kuudesta' is back (-sta), 'seitsemään' is front (-ään).
The clock
Finnish traditionally separates hours and minutes with a period: klo 9.15, klo 14.30 (the 24-hour clock is standard in writing). The colon form 9:15 is common from digital displays, but the period is the classic Finnish spelling. Note that here the period is not an ordinal marker — it is simply the hour–minute divider.
Juna lähtee klo 14.30.
The train leaves at 14:30. — Finnish traditionally divides hours and minutes with a period.
Common Mistakes
❌ Se maksoi 1,000,000 euroa.
Incorrect — the comma is a decimal separator; thousands take a space.
✅ Se maksoi 1 000 000 euroa.
It cost 1,000,000 euros.
❌ Piin arvo on 3.14.
Incorrect — Finnish uses a decimal comma, not a point.
✅ Piin arvo on 3,14.
The value of pi is 3.14.
❌ Asun 3 kerroksessa.
Incorrect — without the period, '3' is the cardinal 'three', not 'third'.
✅ Asun 3. kerroksessa.
I live on the 3rd floor.
❌ Tapaaminen on 12.6.
Incorrect if you mean 6 December — Finnish dates run day.month, so 12.6. reads as the 12th of June; writing the month first is an Anglo habit.
✅ Tapaaminen on 6.12.
The meeting is on the 6th of December.
❌ Nousin bussi 7:aan.
Incorrect — 'seitsemän' has ä, so the ending is front: 7:ään.
✅ Nousin bussi 7:ään.
I got on bus 7. — the ending harmonises to the spoken word 'seitsemään'.
Key Takeaways
- Decimal comma, spaced thousands: 3,14 and 1 000 000 (the exact reverse of English).
- Currency and percent signs follow the number after a space: 10 €, 50 %.
- Dates are day.month.year, each part with a period: 6.12.2017.
- Ordinals need a period as figures: 3. = kolmas; a bare 3 is the cardinal three.
- A colon glues a case ending onto a digit (2:ssa, 5:ltä, 7:ään), and that ending harmonises to the spoken number word, not the digit.
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Start learning Finnish→Related Topics
- Dates and the CalendarA2 — Writing and saying Finnish dates — the day is an ordinal, the month bends to genitive or partitive, and 'on' a day uses the essive.
- Fractions and DecimalsB1 — Finnish fractions built on ordinal + osa, the lexical puoli, and the decimal comma read as pilkku — plus the partitive that measured amounts demand.
- Telling the TimeB1 — How to ask and tell the time in Finnish — including the puoli trap, where 'half two' means 1:30, and the ablative for saying 'at' a time.
- Punctuation and the Comma RuleB1 — Finnish commas are grammatical, not rhythmic: every subordinate clause is fenced by commas — unlike English — while ja/tai joining a shared subject need none.
- Ordinal Numbers: ensimmäinen, toinen, kolmasA2 — The Finnish ordinals from first to tenth — the two irregular low forms and the regular -s series built on the cardinal.