The information required for a numerology reading depends on the reading.
A character and life path reading provides interpretations based on the major name and birth date numbers — perhaps all of the core numbers.
Such a reading generally provides the best results when the full birth name and the full birth date are provided. Exceptions are discussed further below.
Because numerology interpretations are based on mathematical calculations, providing incorrect or spoofed information to a numerologist or a numerology calculator, of course, results in incorrect or spoofed results. Accurate numerology calculations are not cheat‑able.
There are specialized readings where different and specific information is required. Some may require only a last name, or only a first or nickname, perhaps only the month and day of birth. Whatever is required needs to be provided for the best reading.
In other words, a numerologist or numerology calculator requires specific information for whatever reading the calculator is designed to provide.
Specialized readings aside, the foundational numerology reading is the character and life path reading referred to above.
Foundational numerology readings can be obtained as free online readings that provide basic information for some numerology chart positions. And as more comprehensive professional readings that can be purchased online.
Your Name for Numerology Readings describes what a full birth name is for foundational numerology readings.
An exception to the full birth name foundational reading requirement is when a person has changed their name a sufficient period of time ago (perhaps years) so they no longer identify themselves with the birth name. With that circumstance, the numerology reading may resonate better with the new name than with the birth name (although the birth name energy never goes completely away).
Another exception to the full birth name requirement is when a foundational reading is done for a professional name. An actor, writer, singer, or other professional may have a name specifically for their career.
If the birth name is known and not the date of birth, or vice versa, a foundational reading can be done with the available information.
Only a few numerology chart positions require both name and birth information for their calculation. The rest use only the name information or only the birth information and those parts of the reading may be obtained. Free online numerology calculators linked from the core numbers article that can be used for that purpose.
The full birth name generally is best when getting a foundational numerology reading. As noted, other names can be provided, but the reading will be different than what it would otherwise be.