Ashta-kuta: Vedic compatibility by the Moon
Ashta-kuta compares the Moon nakshatras and signs of two people in the sidereal zodiac. Eight checks, each worth its own number of gunas, up to 36 in total.
Where the points come from
Each kuta compares one quality: temperament, how the signs relate, the rhythm of the nakshatras. A full match gives the maximum, a partial one a share, a mismatch zero. The kutas the tradition rates higher weigh more: Nadi gives up to 8 gunas, Varna only 1.
Why two orders
The tradition counts a couple by gender: some kutas are not symmetric, and the result depends on who is "first" in the couple. We do not ask for gender and show both orders, so the site may show a range, such as 21 to 24 gunas.
Why the exact time matters
The Moon crosses a nakshatra in about a day. Without a birth time it may fall in the next nakshatra and the points change. So without both times we do not calculate ashta-kuta and explain what it is instead.
Doshas
The tradition calls some combinations doshas, such as Nadi dosha when both Nadis are the same. The book names them together with the rules by which the tradition cancels them, without scaring anyone.