Number, Date, and Time Errors | German Grammar

Numbers feel like neutral, universal territory — surely a 7 is a 7 in any language. But German bundles a handful of conventions that run directly against English habits, and the errors cluster tightly: you say the units before the tens, you read clock times "ahead" of where English does, you swap the decimal point and the thousands comma, you drop the in before a year, and you keep measure words singular after a count. None of these are deep grammar — they are conventions — but because they collide with deeply automatic English habits, learners get them wrong long after they have mastered harder structures. This page sorts the traps and fixes them with incorrect → corrected pairs.

Error 1: units-before-tens word order

This is the single most pervasive number error. German reads two-digit numbers units first, then tens, joined by und: einundzwanzig is literally "one-and-twenty". English speakers transfer the English order and produce non-words like zwanzigeins or hyphenated calques like zwanzig-eins.

❌ Ich bin zwanzigeins Jahre alt.

Wrong — units come first: 'einundzwanzig', and it is one word.

✅ Ich bin einundzwanzig Jahre alt.

I'm twenty-one years old.

The whole number is written as one unbroken word, no spaces and no hyphens, all the way up: vierundsechzig (64), neunundneunzig (99), zweihundertsiebenunddreißig (237). The units-and-tens flip happens at every level, so inside a big number the last two digits still invert.

❌ Das Buch hat dreihundert-fünfzig-zwei Seiten.

Wrong — no hyphens, and the last two digits flip: 'dreihundertzweiundfünfzig'.

✅ Das Buch hat dreihundertzweiundfünfzig Seiten.

The book has three hundred and fifty-two pages.

✅ Sie wohnt seit fünfundvierzig Jahren hier.

She's lived here for forty-five years.

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This order is not random or archaic — it is the same logic behind the English nursery rhyme "four and twenty blackbirds". English used to do it too, and German simply kept it. Hearing a phone number read aloud is where it bites hardest: a German says vierundsechzig and you must mentally write the 4 after the 6.

Error 2: the halb drei reversal (the highest-consequence error)

In English, "half three" (where it is used at all) means 3:30 — half past three. In German, halb drei means 2:30 — it counts the half hour you are climbing toward three. So halb + a number means "thirty minutes before that number". Misreading this is the costliest error on the page, because it makes you an hour off and you miss appointments.

❌ Wir treffen uns um halb drei — also um 15:30 Uhr.

Wrong — 'halb drei' is 2:30, not 3:30.

✅ Wir treffen uns um halb drei, also um 14:30 Uhr.

We're meeting at half past two, i.e. at 2:30.

✅ Der Zug fährt um halb neun ab.

The train leaves at 8:30.

The mental fix: halb X points at the hour that is half-built. At 2:30 you are halfway through the journey to three o'clock, so the clock is "half three" in the sense of half of the way to three. The related quarter expressions follow the same forward-looking logic in much of Germany: Viertel drei = 2:15 (a quarter of the way to three) and dreiviertel drei = 2:45 (three quarters of the way). These regional forms confuse even native speakers from other regions, so the safe, universally understood options are Viertel nach zwei (2:15) and Viertel vor drei (2:45).

✅ Es ist Viertel vor drei.

It's a quarter to three (2:45).

✅ Es ist Viertel nach zwei.

It's a quarter past two (2:15).

Error 3: am / im / um confusion with time expressions

English uses "at", "in", and "on" by different rules than German uses um, im, and am, and learners map them wrongly. The reliable split: um for clock times, am for days and dates, im for months, seasons, and years-with-Jahr.

❌ Der Kurs beginnt in acht Uhr.

Wrong — clock times take 'um': 'um acht Uhr'.

✅ Der Kurs beginnt um acht Uhr.

The course starts at eight o'clock.

❌ Ich habe am Januar Geburtstag.

Wrong — months take 'im': 'im Januar'.

✅ Ich habe im Januar Geburtstag.

My birthday is in January.

✅ Wir sehen uns am Montag.

We'll see each other on Monday. ('am' for days)

The logic, once you see it, is consistent: um answers Um wie viel Uhr? (at what point on the clock), am (= an dem) attaches to a named day or calendar date, and im (= in dem) wraps a longer stretch — a month, a season, a year. See prepositions of time for the full set.

Error 4: "in" before a bare year

English says "in 1990". German does not put any preposition before a four-digit year standing alone — you say the year by itself, or you use the fuller phrase im Jahr(e) 1990. Inserting in is one of the most recognizable English-speaker tells.

❌ Ich bin in 1990 geboren.

Wrong — no 'in' before a bare year: '1990' alone, or 'im Jahr 1990'.

✅ Ich bin 1990 geboren.

I was born in 1990.

✅ Die Mauer fiel im Jahr 1989.

The wall fell in 1989. (the longer phrase with 'im Jahr')

Both versions are correct German; what is wrong is the hybrid in 1990. Note also that years up to 1999 are read in hundreds: 1990 is neunzehnhundertneunzig, not eintausendneunhundertneunzig. From 2000 on, German switches to thousands: zweitausend, zweitausendvierundzwanzig (2024). See dates, days, and years.

Error 5: the swapped decimal and thousands marks

German and English use the comma and the period in opposite roles. German uses a comma for the decimal point and a period (or a thin space) for grouping thousands. So English 3.14 is German 3,14, and English 1,000 is German 1.000. Getting this backwards can turn a price into nonsense.

❌ Die Zahl Pi ist ungefähr 3.14.

Wrong — the decimal mark is a comma in German: '3,14'.

✅ Die Zahl Pi ist ungefähr 3,14.

The number pi is about 3.14.

❌ Die Stadt hat 1,000 Einwohner.

Wrong — to a German reader this looks like one point zero; use a period: '1.000'.

✅ Die Stadt hat 1.000 Einwohner.

The town has 1,000 inhabitants.

A decimal comma is read aloud with Komma: 3,5 is drei Komma fünf. And a price like 3,50 € is normally spoken as drei Euro fünfzig — the unit slots between the whole and the fractional part. See fractions, decimals, and arithmetic.

✅ Das macht drei Euro fünfzig.

That comes to three fifty (3,50 €).

Error 6: ordinal dates without the -ten ending

In a date, the day is an ordinal number and must carry its ending — der dritte Mai, am dritten Mai. English speakers say the cardinal ("the three of May" calque) or drop the inflection, producing am drei Mai or am dritte Mai. The number is also written with a period as the ordinal marker: 3. Mai.

❌ Wir heiraten am drei Mai.

Wrong — the day is an ordinal and takes the dative ending: 'am dritten Mai'.

✅ Wir heiraten am dritten Mai.

We're getting married on the third of May.

✅ Heute ist der erste Juni.

Today is the first of June. ('der erste' — nominative ordinal)

Why the -ten? After am (= an dem) the date is in the dative, so the ordinal adjective takes the dative ending -en: der dritte → am dritten. When the date is the subject (Heute ist der erste Juni) it stays in the nominative: der erste. See ordinal numbers.

Error 7: pluralizing currency and measure units

After a number, German keeps masculine and neuter currency and measure words singular: zehn Euro, fünf Kilo, drei Glas Wasser, zwei Meter. English forces the plural ("ten euros, five kilos"), and learners carry the -s over.

❌ Das kostet zehn Euros.

Wrong — currency stays singular after a number: 'zehn Euro'.

✅ Das kostet zehn Euro.

That costs ten euros.

❌ Ich hätte gern fünf Kilos Kartoffeln.

Wrong — measure words stay singular: 'fünf Kilo'.

✅ Ich hätte gern fünf Kilo Kartoffeln.

I'd like five kilos of potatoes.

The rule applies to masculine and neuter units of money, weight, measure, and quantity: der Euro, das Kilo, das Gramm, der Meter, das Glas, das Stück, das Paar. Feminine units do take their plural: zwei Flaschen Wasser, drei Tassen Kaffee, fünf Mark historically but zehn Kronen. And the substance counted follows directly with no preposition — German has no equivalent of English "of": ein Kilo Äpfel, not ein Kilo von Äpfeln. See quantities and measurements.

✅ Wir brauchen zwei Flaschen Wein und ein Kilo Käse.

We need two bottles of wine and a kilo of cheese. (feminine 'Flaschen' pluralizes; 'Kilo' doesn't)

Error 8: Million and Milliarde are nouns, not part of the number-word

Up to 999.999 a German number is written as one solid word. But Million, Milliarde, and Billion are separate, capitalized feminine nouns that pluralize with -en. Learners either glue them into the number-word or fail to pluralize them.

❌ Die Firma hat zweimillionen Euro verdient.

Wrong — 'Million' is a separate noun and pluralizes: 'zwei Millionen Euro'.

✅ Die Firma hat zwei Millionen Euro verdient.

The company earned two million euros.

✅ Eine Million Menschen leben hier.

One million people live here. (singular 'eine Million')

So: eine Million (sg.), zwei Millionen (pl.), drei Milliarden (3 billion). The word before Million is eine, not ein, because the noun is feminine. See hundreds, thousands, millions.

Error 9: the Billion false friend

This one is a genuine numerical trap, not just a style issue. German Billion does not equal English "billion". German uses the long scale: eine Milliarde = 1,000,000,000 (English "billion"), and eine Billion = 1,000,000,000,000 (English "trillion"). Translating Billion as "billion" understates the figure by a factor of a thousand.

❌ Die Staatsschulden betragen zwei Billionen Euro — also zwei Milliarden.

Wrong — German 'Billion' is English 'trillion'; 'zwei Billionen' = two trillion.

✅ Die Staatsschulden betragen zwei Billionen Euro — auf Englisch „two trillion“.

The national debt is two trillion euros (German 'Billionen' = English 'trillions').

✅ Eine Milliarde sind tausend Millionen.

A 'Milliarde' is a thousand million — that's the English 'billion'.

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Lock in the ladder: Million = million, Milliarde = billion, Billion = trillion. The cognate that looks easiest (Billion) is the dangerous one.

Error 10: jeden Tag with a preposition

To say "every day", "every week", "every year", German uses a bare accusative phrase: jeden Tag, jede Woche, jedes Jahr — no preposition. English "every day" tempts a calque, and German learners over-correct into the stiff prepositional an jedem Tag, which sounds bookish and unnatural in everyday speech.

❌ Ich gehe an jedem Tag joggen.

Stilted — drop the preposition: 'jeden Tag'.

✅ Ich gehe jeden Tag joggen.

I go jogging every day.

✅ Wir treffen uns jede Woche.

We meet every week.

This is the accusative of time: definite, repeated time spans go in the bare accusative. The masculine jeden Tag shows the accusative ending clearly; jede Woche (fem.) and jedes Jahr (neut.) look like the nominative but are equally accusative.

Quick reference

Trap	English habit	Correct German
Two-digit order	twenty-one	einundzwanzig (units first, one word)
halb + hour	half three = 3:30	halb drei = 2:30
Clock vs month vs day	at / in / on	um acht Uhr, im Januar, am Montag
Bare year	in 1990	1990 or im Jahr 1990
Decimal mark	3.14	3,14 (comma)
Thousands mark	1,000	1.000 (period)
Ordinal date	am drei Mai	am dritten Mai
Currency / measure	ten euros, five kilos	zehn Euro, fünf Kilo (singular)
Big nouns	zweimillionen	zwei Millionen (separate, plural)
Billion	billion = 10⁹	Billion = 10¹²; 10⁹ is Milliarde
Every day	an jedem Tag	jeden Tag (bare accusative)

Key takeaways

Two-digit numbers go units-before-tens and are written as one word: einundzwanzig.
halb drei is 2:30 — it counts toward the coming hour. This is the error that costs you appointments.
Use um for clock times, am for days and dates, im for months, seasons, and years-with-Jahr; a bare year takes no preposition.
Swap your separators: German decimal = comma (3,14), thousands = period (1.000).
Dates use ordinals with endings: am dritten Mai, written Mai
.
Currency and masculine/neuter measure units stay singular after a number: zehn Euro, fünf Kilo; the substance follows with no of.
Million, Milliarde, Billion are separate feminine nouns — and German Billion = English trillion.

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