Two systems, two answers
Numerology has two main systems for turning letters into numbers: Pythagorean and Chaldean. They agree on how to use a birth date, but they give different values to the letters of a name, so the same name can produce a different Destiny, Soul Urge or Personality number. Knowing which system a reader or calculator uses is therefore important. Mixing the two in one reading is a common source of confusion.
Both are symbolic systems, and neither has been shown by scientific studies to predict personality or events. The choice is a matter of tradition and of what you find useful.
The Pythagorean system
The Pythagorean system is the most popular in the United States and Europe. It assigns the numbers 1 to 9 to the letters of the alphabet in order, then starts again. A to I are 1 to 9, J to R are 1 to 9, and S to Z are 1 to 8.
| Number | Letters |
|---|---|
| 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 |
The name is linked with the Greek thinker Pythagoras, who saw numbers as the order behind the world. The letter chart itself is much later. It was set out in its present form by writers in the early twentieth century, and it is simple to learn and to do by hand. It is the system used on this site for the pages about the Destiny number and the Soul Urge number.
The Chaldean system
The Chaldean system is older and is linked with ancient Babylon. It assigns the numbers 1 to 8 only, and the number 9 is left out of the letter chart because it is held to be sacred. The values follow the sound and vibration of each letter, not its place in the alphabet.
| Number | Letters |
|---|---|
| 1 | A, I, J, Q, Y |
| 2 | B, K, R |
| 3 | C, G, L, S |
| 4 | D, M, T |
| 5 | E, H, N, X |
| 6 | U, V, W |
| 7 | O, Z |
| 8 | F, P |
Another feature is the use of compound numbers. The Chaldean reader adds the letter values of a name to get a total between 10 and 52 and reads the meaning of that compound number first, and then of the single digit it reduces to. Each compound number has a traditional meaning, often a warning or an image such as a crown or a wheel. A name that totals 18 would be read as 18 and then as 9.
A worked comparison
Take the name Paul.
In the Pythagorean system, P is 7, A is 1, U is 3 and L is 3. The total is 14, and 1 + 4 = 5. The number is 5.
In the Chaldean system, P is 8, A is 1, U is 6 and L is 3. The total is 18, and 1 + 8 = 9. The number is 9.
The same four letters give a 5 in one system and a 9 in the other. A 5 is read as curious and changeable, and a 9 as compassionate and idealistic. This is why a person may find that one system describes them well and the other does not.
Key differences
Letter values. Pythagorean runs in order and uses 1 to 9. Chaldean follows sound and uses 1 to 8.
The number 9. Pythagorean uses it freely. Chaldean treats it as sacred and does not assign it to a letter, though it can appear as a total.
The name used. Pythagorean readers usually use the full birth name. Chaldean readers often prefer the name a person is commonly known by, since they hold that the vibration of the name in daily use is what matters.
Date numbers. Both use the birth date in a similar way. Chaldean readers often give the day of birth a larger role and read it alone as the main number, called the psychic number.
Compound numbers. Chaldean readers give them great weight. Pythagorean readers rarely do.
Master numbers. Pythagorean readers keep 11, 22 and 33. Chaldean tradition does not use master numbers in the same way.
Popularity. Pythagorean is common in Western books and apps. Chaldean is common in the Middle East, in India and in some British traditions.
How to choose
If you are new to numerology, begin with the Pythagorean system. It is easy to calculate, it matches most books and calculators, and the meanings are widely written about. If you are interested in an older tradition, or want to look at the name you use every day, try the Chaldean system and read it separately.
Whichever you pick, stay with it for the whole reading. If you compare results, label them clearly. A number from one system should not be read with the meaning list of the other.
Which is more accurate?
Neither is more accurate in a scientific sense. Studies of numerology have not found that either system predicts traits. Each is internally consistent. Many users choose the system whose descriptions feel closer to their own experience, and this is a personal judgment and not a proof.
Related numbers
The birth date number, the Life Path number, does not depend on the system, because it uses only digits. Only the name numbers change. For an overview of all the numbers, see numerology. For a grid view of the date, see the Lo Shu Grid. For the yearly cycle, see the Personal Year.