In Chaldean numerology, the Total Name Number (TNN) and the Birth Number (the day of the month on which a person was born, such as the 17th) are generally regarded as the two strongest numbers in the numerological chart. Individual days of the month are already mentioned in the Bible. Both numbers have approximately equal strength.
First names and surnames are generally considerably weaker, although the first name is usually somewhat stronger than the surname. Much depends on whether people primarily address us by our first name or by our surname.
The Life Path Number is also powerful. Opinions about its strength, however, differ. Some numerologists deny its significance altogether (e.g., Cheiro), while others regard it as a key date number (e.g., Montrose). It appears to be somewhat stronger than the first name and surname, but weaker than the TNN and Birth Number.
The Bridge Number of the initials, the Goal Number between the Birth Number and the TNN, and the number formed by all the consonants have approximately the same strength as the numbers of the first name or surname. Vowel numbers, by contrast, are weaker than consonant numbers.
Many Chaldean numerologists are allergic to the use of vowels and consonants and regard them as innovations introduced by modern Pythagorean numerology. In my opinion, these numerologists are making a serious mistake. Instead of engaging in an ideological battle against Pythagorean numerology, it would be better to examine actual numerological charts and determine the rules governing the use of these numbers within the Chaldean numerological system. Readers can look at the many short numerological analyses on my blog and form their own opinion about the influence of vowel and consonant numbers.
The consonant and vowel numbers within a first name or surname are indeed very weak in themselves. However, they acquire greater significance when they connect with other numbers. For example, the 3-5-8 chain can, under certain circumstances, represent “money numbers”; 1-3-9 can bring greater masculinity and decisiveness; the combination 2-5-8 can create excessively strong emotions and fears; and the 2-3-5 chain can be associated with purification practices, children, and moral development.
For the time being, I do not practice numerology as a form of business consulting. Even when it comes to friends, however, I am reluctant to suggest that they adopt new first names or surnames. This is a very serious responsibility, and in addition, the new name must actually appeal to the person who will bear it. Even the best practitioners can find it extremely difficult to come up with a suitable name.
The Mystery of Numbers, Luck, Worlds and Planets 