Compatibility tests based on numbers have always been very popular. Numerology compatibility describes the vibrations between people based on their date of birth. Thus a person understands how he / she complements with his better half and can lead a long life together. The most commonly used numerology system is the Pythagorean system of numerology. This kind of test helps a person to decide whether his partner is the right one for him / her. It gives an insight to any relationship and helps analyze the similarity and differences between couples. This also aids a person to make one of the most important decisions of his/ her life.