- Retain the first letter of the name.
- Drop all occurrences of the following letters in other positions: A, E, I, O, U, Y, H, W
- Assign the following number to the remaining letters after the first letter:
Letters 1 B, F, P, V 2 C, G, J, K, Q, S X, Z 3 D, T 4 L 5 M, N 6 R - If two or more letters with the same code are adjacent in the original name or adjacent except for any intervening H or W, omit all but the first.
- Convert the form letter, digit, digit, digit, by adding trailing zeros if less than three digits.
- Drop the rightmost digits if more than three digits.
- Names with adjacent letters having the same equivalent number are coded as one letter with a single number
Surname prefixes are rarely used.