The zodiac that is used in Vedic Astrology, is very different from the one used in Western Astrology. The Vedic system uses the sidereal (fixed) zodiac, which is based on the actual positions of the stars. The zodiac used in Western Astrology is the tropical zodiac, which is based on the seasons and has in principle no particular connection with the position of the stars. The difference between the sidereal and tropical zodiac is called the Ayanamsha. In this century, the difference is around 23 degrees, less than 1 sign.
If you know the sign and degree of a planet in a Western Astrology horoscope, you will have to subtract the Ayanamsha to find the position according to the Vedic method. In many cases (about 75%), the Grahas in the Vedic chart are one sign prior to the Western chart. For example three quarters of the people who think of themselves of being a “Virgo” are actually a “Leo” in Vedic