Before you start jumping to any conclusions, let me tell you that for marriage purpose both the horoscopes must be thoroughly matched by an experienced astrologer. This is done based on the planetary combinations of the ascendant or lagna, all the 9 planets, the nakshatra or birth star based koota/guna matching, mangala dosha and also the navamsa charts matching. Marriage is a life long association and must be taken seriously.
However to get a rough general idea you can check the matching of the Five Astro-signs – the sun sign, the rasi or moon sign, the lagna or ascendant and the nakshatra based koota/guna matching and also the Chinese sign.
The matching is always done from the girl’s Nakshatra to the boy’s Nakshatra. Check the girls Nakshatra vertically down and match it with the boys Nakshatra given along the same row. For example, if the girl’s Moon is in Aries and in the Nakshatra Krittika 1st quarter and the boy’s moon is in Libra and Chitra 3rd quarter, you note the star# of both, from list of Nakshatras. The girl’s Nakshatra is #3 & the boy’s is 14. From the girls Nakshatra # 3 in the vertical list check along the row till you come to the boy’s Nakshatra #till you come to the column under the boys Nakshatra #. In this case the Koota Matching score is 27 points, or 27 Gunas.
A Guna matiching score of 18 is the minimum required for compatibility. The higher the score, the better it is. Please note that this Guna matching is not the only thing for astrological marriage matching. You need to get the horoscopes matched by an experienced astrologer.