This calculator uses the equal house system and the actual size of the constellations in the sky known as True Sidereal Astrology.
Resources: Chart Key | How to Read a Birth Chart | Order & Customize | Professional Reading
(Note: this system uses the midpoints between constellations. Planets within three degrees of another sign should be considered a blend of both signs.)
Chart is accurate within 1 degree for birth dates within the past 100 years.
New to Sidereal Astrology? Watch this short video explaining it in detail.