Greek Numerals

How Greek numerals work

What do the 27 signs stand for?

The alphabetic system, also called Ionic or Milesian numerals, gives each of 27 signs a fixed value. The first nine letters stand for 1 to 9, the next nine for 10 to 90, and the last nine for 100 to 900. Because the plain alphabet has only 24 letters, three old letters fill the gaps: stigma for 6, koppa for 90 and sampi for 900. That is why zeta is 7 and eta is 8 rather than 6 and 7.

How are the signs combined?

It is a sign-value system: the values of the letters are added. 241 is σμα, which is 200 + 40 + 1. The order does not change the value, but by convention the letters run from largest to smallest, and the converter reads only that order. Since each of the three groups has nine signs, no sign repeats: 400 is υ and not σσ, and 22 is κβ, never ιιββ.

What are the keraia and the lower keraia?

How do you mark a number and the thousands?

A keraia ʹ after the last letter marks the string as a number, so Βʹ is 2 and plain Β is just a letter. Modern Greek uses one keraia at the end of the whole number. The thousands use a second mark, the lower left keraia ͵ (U+0375, GREEK LOWER NUMERAL SIGN), in front of a units letter: ͵Α is 1000 and ͵Θ is 9000. Wikipedia’s example is 2019, written ͵ΒΙΘʹ.

What about overbars and fractions?

Older manuscripts showed numbers with a bar over the letters, for example the number 666 as an overbarred χξϛ in medieval copies of the Book of Revelation. The converter writes the modern mark and not the overbar, which plain text cannot carry.

Fractions put the keraia after the denominator. γʹ means one third, and δʹ one fourth. A special sign, ∠ʹ, meant one half. This tool does not convert fractions.

What are stigma, koppa and sampi in Unicode?

Koppa has a second encoding, GREEK LETTER ARCHAIC KOPPA (U+03D8) and GREEK SMALL LETTER ARCHAIC KOPPA (U+03D9), for the older Q-shaped letter. Fonts and web sources differ on which one they use for 90, so the converter writes the U+03DE and U+03DF pair and reads both. If you copy a numeral from elsewhere and it will not convert, the usual cause is a Latin look-alike: Α Β Ε Ζ Η Ι Κ Μ Ν Ο Ρ Τ Υ Χ all have a Latin twin, and the converter tells you which one it found.

What were Attic numerals?

The alphabetic system sat beside an older Athenian scheme in classical times. Attic numerals, also called acrophonic or Herodianic, were built from the initial letters of the number words and repeated like Roman numerals.

Repeats are written up to four times, so 38 is ΔΔΔΠΙΙΙ. Fifty, 500, 5,000 and 50,000 combine a Π with a small power-of-ten letter. Unicode encodes the Attic signs in the Ancient Greek Numbers block, for example U+10144 GREEK ACROPHONIC ATTIC FIFTY. According to Wikipedia, inscriptions using Attic numerals date from 454 BCE to 95 BCE. We do not convert them: the compound signs sit in a separate Unicode block and depend on font support.

Where are the letter numerals still used?

Modern Greece counts in Arabic digits. The letter numerals remain for ordinals and wherever English uses Roman numerals: the Greek name of Philip II of Macedon ends in Βʹ, and sub-sections of Greek manuscripts are sometimes numbered αʹ, βʹ, γʹ. If you need a symbol for a tattoo or an outline, check the sign twice, because ς and ϛ and the Latin-looking capitals are easy to confuse. See the tattoo guide.

How do you type the marks?

There is no key for the keraia on most keyboards, so copy it or type U+0374 by code. The Greek letters themselves are on the Greek alphabet page, and how to type Greek letters covers keyboards and shortcuts. The numeral marks are a good example of why Unicode has near-duplicate characters: the keraia (U+0374) and a modifier letter prime (U+02B9) are canonically equivalent, so a normalising tool may swap one for the other without changing what you see.

Whichever sign you need, Greek numerals use the same Unicode letters as the alphabet plus the keraia marks, so a font with Greek and the U+0374 and U+0375 glyphs is enough.

Sources

• Wikipedia, Greek numerals (the 27-sign scheme, keraia and lower keraia, worked examples such as 241, 666 and 2019, Attic numerals, zero)
• Unicode Greek and Coptic code chart (PDF) (U+0374, U+0375, stigma, koppa, sampi)
• Unicode Ancient Greek Numbers chart (PDF)
• Every code point and name on this page was checked with Python 3 unicodedata. The converter’s logic is unit-tested: all 9,999 numbers round-trip in each case and stigma option.