Sun, Moon and rising sign
Start with the zodiac sign calculator: your birth date gives your Sun sign, and adding a birth time and place settles cusp birthdays by computing the Sun’s exact position. The Moon sign calculator needs a time as well, because the Moon changes sign every two and a half days; it also shows the Moon phase at your birth. The rising sign calculator finds your ascendant, which changes about every two hours, so an accurate birth time matters most there.
Birth chart and compatibility
The birth chart calculator draws a natal chart wheel with the Sun, Moon and planets, the North Node, Ascendant, Midheaven, 12 houses (Placidus or Whole Sign) and the major aspects with their orbs. The zodiac compatibility tool compares two Sun signs and gives separate love, friendship and work scores. Its rules are shown openly: a base score from the angle between the signs, adjusted for elements and modalities. Each of the 78 sign pairs has its own page.
Chinese zodiac and a note on accuracy
The Chinese zodiac calculator finds your animal, element and yin or yang using the real Chinese New Year date of your birth year, so January and February birthdays are handled correctly. Planet positions come from the open-source astronomy-engine library and are astronomically accurate, and nothing you enter leaves your browser. Astrology itself, however, has no scientific basis: the interpretations describe a cultural tradition and are meant for entertainment, not for decisions about health, money or relationships.