Pythagorean vs Chaldean numerology
Two mappings, two answers, and almost no calculator tells you which it used.
2 min read · Published 20 August 2026
First, the answer
Pythagorean numerology assigns letters to numbers 1 to 9 in alphabetical order: A is 1, B is 2, through to I is 9, then repeating. Chaldean assigns values 1 to 8 by claimed sound vibration and reserves 9 as sacred, assigned to no letter. They produce different numbers for the same name. Pythagorean is far more common in English-language numerology and is almost certainly what your calculator used.
The two mappings
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|
| A J S | B K T | C L U | D M V | E N W | F O X | G P Y | H Q Z | I R |
Chaldean does not follow alphabetical order, and no letter is assigned 9. A name the two systems score differently produces a different total.
The differences that count
| Modern Pythagorean | Modern Chaldean | |
|---|---|---|
| Value range | 1 to 9 | 1 to 8, with 9 reserved |
| Basis of assignment | Alphabetical position | Claimed sound vibration |
| Name used | Usually the full birth name | Usually the name you go by |
| Reduction | Reduce to a single digit, keeping master numbers | Compound numbers before reduction carry their own meanings |
| Prevalence in English | Dominant | Minority, but with a strong following |
The third row is the substantive one. Pythagorean reads the name on your birth certificate; Chaldean reads the name people call you. Two inputs, two answers.
Pythagorean, because it is checkable. Chaldean's 'sound vibration' is a claim nobody has ever measured.
The compound number idea
Chaldean practice reads the two-digit total before reduction as carrying meaning. A name totalling 37 and one totalling 19 both reduce to 1, and Chaldean reads them differently. Pythagorean reduces straight through, except for master numbers. They disagree about whether the intermediate total is data or an artefact.
Which should you use
The criteria are practical, since neither has any accuracy to compare. Pythagorean if you want your numbers to match most books and calculators. Chaldean if the compound-number layer interests you, or if the name you go by seems the better input, given the problems with birth names.
What you should not do is calculate both and keep the number you prefer. AsterNym uses Pythagorean and says so on the numerology page, alongside the Y-handling convention and the reduction rule.
What is the difference between Pythagorean and Chaldean numerology?
Pythagorean assigns letters values 1 to 9 in alphabetical order. Chaldean assigns 1 to 8 by claimed sound vibration and reserves 9. They produce different numbers for the same name.
Why does Chaldean numerology have no 9?
The number is held to be sacred in that system and is not assigned to any letter, though it can still appear as a total.
Is Chaldean numerology really ancient?
The evidence for continuity with Babylon is thin. Today's version was shaped by twentieth-century occult writing.
Santiago Garcias