Pythagorean Numerology
Pythagorean numerology is the numbering system most Western numerologists use today, attributed to the Greek philosopher Pythagoras. It assigns each letter of the alphabet a value from 1 to 9 in strict alphabetical order — A=1 through I=9, then J=1 again — and applies that table to a person's full birth name. Master numbers 11, 22, and 33 are kept rather than reduced further.
Related terms
Common questions
- How old is the Pythagorean system?
- It's credited to Pythagoras in ancient Greece, though the letter-value method used today was formalized much later. It's now the most common system in Western numerology books and calculators.
- Does Pythagorean numerology use the birth name or a nickname?
- It uses the full name exactly as it appears on the birth certificate, not a nickname or a name someone goes by day to day.
- How does it differ from Chaldean numerology?
- Chaldean numerology assigns letter values by sound rather than alphabet position, uses only 1 to 8, and typically reads the name a person currently uses instead of the birth name.
Last reviewed: August 12, 2026