What is the difference between DIN 5007-1 and DIN 5007-2?

DIN 5007-1 is the dictionary rule: umlauts sort exactly like their base vowel, so ä = a, ö = o and ü = u. DIN 5007-2 is the phone-book rule: umlauts expand to two letters, so ä = ae, ö = oe and ü = ue, which separates names like Müller and Mueller.

In both DIN rules the sharp-s ß is treated as ss for ordering. So Straße and Strasse sort to the same position, just before words continuing with a different letter.

Which rule should I use for a list of surnames?

Use DIN 5007-2 for phone books, member directories and any alphabetical name index. It is the rule German telephone directories follow, and it keeps the umlaut and digraph spellings of a name close together.

Why does Müller sort near Mueller in the phone-book rule?

Under DIN 5007-2, Müller is treated as Mueller for comparison, so the two spellings collate to adjacent positions. Under DIN 5007-1, Müller is treated as Muller and sorts among the plain-u names instead.

Does sorting happen on my device?

Yes. The list is sorted entirely in your browser using the selected DIN rule, so nothing you paste leaves your machine.

German Alphabetical Sort

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Alphabetising German text is not as simple as a plain Unicode sort, because the umlauts ä, ö, ü and the sharp-s ß have no fixed position in the basic Latin order. Germany’s DIN 5007 standard defines two accepted rules, and which one is correct depends on whether you are building a dictionary or a name index. This tool applies either rule to a list you paste in.

How it works

Before comparing two words, each is transformed into a sort key in lowercase, then the umlauts are replaced according to the chosen rule:

DIN 5007-1 (dictionary)   ä → a   ö → o   ü → u   ß → ss
DIN 5007-2 (phone book)   ä → ae  ö → oe  ü → ue  ß → ss

The keys are then compared character by character. When two keys are equal — for example Müller and Muller both reduce to muller under DIN 5007-1 — the original spellings are used as a stable tie-break so the order stays deterministic.

Which rule to use

Use DIN 5007-1 for glossaries, dictionaries and indexes where you want Apfel and Äpfel to sit next to one another. Use DIN 5007-2 for telephone directories, customer lists and any roster of surnames, because it keeps umlaut spellings (Müller) and their ASCII variants (Mueller) collated together, which matters when people may have registered either form.

Example

Given the names Müller, Mueller, Muller and Maier, DIN 5007-1 orders them Maier, Muller, Müller, Mueller (umlaut counts as plain u, then ue follows). DIN 5007-2 orders them Maier, Mueller, Müller, Muller, pulling the ae-style spellings together. Both rules place Straße and Strasse at the same point because ß equals ss everywhere.