Numerology is an ancient system of divination that seeks information encrypted in the universe in numbers. It uses magical thinking and supposes that a person's name (which alludes to their essence) can be analysed numerically to yield useful information about that person character and destiny. It also ascribes significance to birth dates (the so called life path number) and other dates on the assumption that the associated numbers bear some kind of cosmic echo of the influences operating at the time.
The first stage in a numerological analysis is to convert the letters of a name into a corresponding number string. Numerologists use different letter-to-number transformations (mappings) to do this.
CONTEMPORARY: Mapping of the modern alphabet sequentially against the numbers 1 to 9 is commonly known as Pythagorean Numerology. Thus A=1, B=2, C=3, etc. and then the letters wrap around.
HEBREW / GREEK commonly known as Chaldean Numerology is more arcane and is based on number associations with ancient letters.
Both methods are available on this calculator and you can compare their results in the history window. I have also created a purely Caldean Numerology Calculator and a numerology calculator that maps the 26 letters of the alphabet to the first 26 letters of pi.
Having generated a sequence of numbers, the numerologist then analyses those numbers. This is done by adding all of the digits of the number string together. If that yields a multi-digit number, then those digits are added together again. The process is repeated until only one digit remains. This digit is the digital root. Some exceptions might be made for important magical double digit numbers like 11. Further analyses might involve counting vowels or consonants.
The significance of the (root) name numbers and life path numbers is open to interpretation, to say the least. The number 1 is obviously primary and invokes leadership, whereas the number 9 suggests some kind of pinnacle, being the highest number. Numbers might also have associations with astrological things like planets. Not only that, but even numbers tend to be associated with female traits and odd numbers with male traits. All of the interpretations include positive and negative aspects. They are a heady brew of antique reasoning, mathematics, the tarot, occult lore, mysticism, religion, and astrology. The very detailed characteristics for each number allow for a nice elastic interpretation.
SCIENCE OF NUMEROLOGY. So far as I know there is no scientific evidence that numerology works. Therefore, no decisions should rationally be made on any numerological divination, whether algorithmic or human.