Chaldean numerology, in full
Three things separate it from the Pythagorean system that dominates English-language numerology. Letter values run 1 to 8, with no letter assigned 9, on the reasoning that 9 is sacred and stands apart. The values follow sound rather than alphabet order, so letters that share a sound can share a number while their neighbours in the alphabet do not. And the reading is done on the name a person actually goes by, not the one on the birth certificate, since practitioners hold that a name only carries weight once it is in use.
The missing 9 has a practical consequence rather than a decorative one. Because no single letter contributes a 9, any total reaching 9 has to be built by addition, which practitioners treat as a meaningful distinction. Published Chaldean charts also differ from one another in places, more than Pythagorean ones do, so two Chaldean readings of the same name can disagree before any interpretation starts.
The name points at ancient Babylonia, and that link is traditional rather than documented. Babylonian scribes did work in a sexagesimal number system, and forms of divination in Mesopotamia are well attested in the surviving record. What is absent is any ancient text containing this chart, which is unsurprising, since the chart assigns values to the Latin alphabet. This site uses the Pythagorean chart throughout and states so on every page that shows one, because the two systems will hand the same person different numbers and neither can be tested against the other.
- Numerology
- Chaldean system
A worked example
The clearest difference is the absent 9. A Chaldean total can reach 9 only by adding several letters, never from one, which changes which names can land there at all. The second difference bites just as hard. Someone recorded as Katherine at birth who has answered to Kate for thirty years is read on Kate in a Chaldean reading and on Katherine in a Pythagorean one, and the two rarely agree.
Sources
Babylonian mathematics used a sexagesimal, base-60 numeral system, which is where 60 minutes in an hour and 360 degrees in a circle come from.
Wikipedia — Babylonian mathematics
See also
Where it comes up on this site
Chaldean numerology: frequently asked
The tradition treats 9 as sacred and keeps it out of the letter chart, so no single letter can contribute one. Totals can still reach 9 once letters are added. The reason given is doctrinal, not mathematical.
There is no documentary basis for it. Babylonian mathematics and Mesopotamian divination are both richly attested, and neither produced this chart, which assigns values to the Latin alphabet rather than to cuneiform. The name signals a claimed lineage.
Pythagorean, everywhere. Every name number on this site comes from that chart.