Wikipedia lists various methods of calculating gematrias.
- Mispar Hechrachi (absolute value) that uses full numerical value of the twenty-two letters. Sometimes its also called Mispar ha-Panim (face number), as opposed to the more complicated Mispar ha-Akhor (back number).
- Mispar Gadol counts the final forms (sofit) of the Hebrew letters as a continuation of the numerical sequence for the alphabet, with the final letters assigned values from 500 to 900. The same name, Mispar ha-Gadol, is also used for another method, which spells the name of each letter and adds the standard values of the resulting string. Mispar Katan calculates the value of each letter, but truncates all of the zeros. It is also sometimes called Mispar Me'ugal.
- Mispar Siduri (ordinal value) with each of the 22 letters given a value from one to twenty-two.
- Mispar Bone'eh (building value) uses the sum of each letter added to the next letter within the word to total the value of the word. Therefore, the value of the word "Achad" (one) is 1 + (1 + 8) + (1 + 8 + 4) = 23.
- Mispar Kidmi (triangular value) uses each letter as the sum of the all the standard gematria letter values preceding it. Therefore, the value of Aleph is 1, the value of Bet is 1 + 2 = 3, the value of Gimmel is 1+2+3=6, etc. It's also known as Mispar Meshulash (triangular or tripled number).
- Mispar P'rati calculates the value of each letter as the square of its standard gematria value. Therefore, the value of Aleph is 1 × 1 = 1, the value of Bet is 2 × 2 = 4, the value of gimmel is 3 × 3 = 9, etc. It's also known as Mispar ha-Merubah ha-Prati'.
- Mispar ha-Merubah ha-Klali is the square of the standard absolute value of each word.
- Mispar Meshulash calculates the value of each letter as the cube of their standard value. The same term is more often used for Mispar Kidmi.
- Mispar ha-Akhor The value of each letter is its standard value multiplied by the position of the letter in a word or a phrase in either ascending or descending order. This method is particularly interesting, because the result is sensitive to the order of letters. It's also sometimes called Mispar Meshulash (triangular number).
- Mispar Mispari spells out the standard values of each letter by their Hebrew names ("Achad" (one) is 1+8+4=13 etc.), and then adds up the standard values of the resulting string.
- Mispar Shemi (also Millui letter "filling"), uses the value of each letter as equal to the value of its name. For example, the value of the letter Aleph is (1 + 30 + 80) = 111, Bet is (2 + 10 + 400) = 412, etc. Sometimes the same operation is applied two or more times recursively.
- Mispar Ne'elam (hidden number) spells out the name of each letter without the letter itself (e.g. "Leph" for "Aleph") and adds up the value of the resulting string.
- Mispar Katan Mispari (integral reduced value) is used where the total numerical value of a word is reduced to a single digit. If the sum of the value exceeds 9, the integer values of the total are repeatedly added to produce a single-digit number. The same value will be arrived at regardless of whether it is the absolute values, the ordinal values, or the reduced values that are being counted by methods above.
- Mispar Misafi adds the number of the letters in the word or phrase to their gematria. Kolel is the number of words, which is often added to the gematria. In case of one word, the standard value is incremented by one.
I have never seen many of these methods used before. What is an example of each type?