Pythagorean System

The default Western method: letters take values 1-9 by their position in the alphabet, repeating (A=1 ... I=9, J=1 ...).

Simple and sequential. It is the system most Western numerology calculators use. The name attaches to Pythagoras by tradition, not by evidence. Letter values: 1: A J S - 2: B K T - 3: C L U - 4: D M V - 5: E N W - 6: F O X - 7: G P Y - 8: H Q Z - 9: I R.

Not: Not the 'correct' or original system. It is one convention among several, and it disagrees with the Chaldean method.

Assigning numbers by alphabet position is a 20th-century convenience, not a discovered law.