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About this tool
Compare two zodiac signs or birth dates and see the traditional aspect, element and modality match between them with a 0-100 compatibility score.
The Zodiac Compatibility Checker compares two sun signs — picked directly or worked out from two birth dates — and scores the pairing from 0 to 100 using the classical aspect between them on the 360° zodiac wheel. Each sign covers 30°, so the gap between two signs lands on a traditional aspect: trine (120°) and sextile (60°) are the easy ones, square (90°) and quincunx (150°) the difficult ones, with a small bonus when both signs share a classical ruling planet such as Mars for Aries and Scorpio. It is written for anyone curious how Western astrology reads their pairing, and it shows the element, modality and polarity behind every score instead of hiding them — for entertainment, not life decisions.
Open Zodiac Compatibility Checker on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
Every score names the aspect, the angle and the element and modality relationship it came from.
Enter two dates and the sign is looked up from the standard tropical date ranges, cusp days flagged.
The score is a fixed weighting of the aspect table, so the same two signs always return the same number.
Signs 120° apart — a trine, four signs apart, always the same element — score highest here at 92, for example Aries with Leo or Taurus with Virgo. Signs 60° apart (a sextile, such as Aries and Gemini) come next at 84, because fire pairs with air and earth pairs with water.
No — opposite signs sit 180° apart and score 74 out of 100 here, above a same-sign pairing at 68. Traditional astrology treats the opposition as strong mutual attraction across a real difference in outlook, such as Aries and Libra or Taurus and Scorpio, rather than as a bad match.
The tool flags it. Sign boundaries move by up to about a day depending on the year and time of birth, so a 21 March or 20 April birthday can land either side. Check a birth chart calculated for your exact time and place if the two signs give very different results.
It is entertainment, not evidence — controlled studies have not found sun sign pairing to predict relationship outcomes. This tool applies traditional Western astrology consistently and publishes its scoring, so treat the number as a conversation starter rather than advice about a real relationship.