Tropical Porphyrius Birth Chart Calculator

This calculator uses traditional tropical zodiac system and Porphyrius house system.

The tropical zodiac is based on the seasons and the position of the Sun at the spring equinox. This is the system used by most Western astrologers. Each sign is exactly 30 degrees, starting with Aries at the spring equinox (March 20-21).

The Porphyrius house system, named after the 3rd-century philosopher Porphyry, is a quadrant system that divides the space between the angles (Ascendant, IC, Descendant, MC) into three equal parts. It is one of the oldest house systems still in use today.

For more features including saving charts, transit charts, synastry charts, and more settings please use True Sky online astrology software.