Love calculators use numerology based on each person's birth date and the letters of their names or astrology based on each person's zodiac sign to determine whether or not two people have compatible characteristics and personalities. In Chinese astrology, there are 12 different animal zodiac signs based on birth year that are divided into four groups based on thinking style and the five elements: earth, wood, fire, water and metal.
Numerology is the belief that there is a mystical or divine connection between specific numbers and life events. Many people use numerology to determine their core numbers that relate to life path, expression, personality and heart's desires. Numerology practitioners believe that life path numbers reveal people's lifestyle, thoughts and patterns of communication, and some life path numbers work well together while others do not.
The traditional Babylonian zodiac, or the 12 horoscope signs, are also grouped by four elements: earth, air, fire and water. Astrologers determine the compatibility of two people by comparing their elements. For example, the most compatible elements for someone with an air sign are fire signs or fellow air signs. Earth and water signs are also typically compatible with one another. In addition to the elements, astrologers may take the seventh house, which is associated with the deep commitment of love, into account when determining compatibility.