Compare two signs, or cross both birth charts in a full synastry with real aspects between the planets.
The tool has two complementary modes. In "By sign" mode, it compares two sun signs from astrology's classic principles, the element (fire, earth, air, water), the modality (cardinal, fixed, mutable), the polarity (yin/yang) and the aspect formed by the distance between them on the wheel (conjunction, sextile, square, trine, quincunx, opposition), and builds love, friendship and work scores with a reading specific to each pair. In "Full chart (synastry)" mode, it goes far beyond the sun sign: you enter each person's birth date, time and city, it computes both real natal charts and measures every major aspect between one person's planets and the other's, Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn and the Ascendant. From those contacts come a composite score, per-area scores (love, communication and commitment), a ranked list of the strongest contacts and an honest synthesis of what draws the couple together and what challenges them. It's the same technique astrologers use to analyze relationships.
Paste the code into your HTML and the tool shows up on your page, without J-Kit's navigation and ads. It still runs in the browser of whoever visits your site.
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src="https://jkit.tools/embed/en-US/zodiac-compatibility"
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></iframe>These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
From each sign's element and modality, its polarity and the aspect formed by the distance between them on the zodiac. Elements that reinforce each other (fire-air, earth-water) and harmonious aspects (trine, sextile) raise the score; squares and quincunxes weigh more on the friction side.
Aries and Leo sit 4 signs apart on the wheel, in the aspect of trine. The smoothest fit of all, within the same element: near-telepathic understanding and instant comfort. Aries brings courage to the bond; Leo, radiance. Sharing the Fire element, they tune in by instinct — thinking and feeling on the same frequency, and the only care is not amplifying the same excesses.
In love, Aries: falls fast and hard; values authenticity and the thrill of the chase. Leo: loves grandly and faithfully; needs mutual admiration and warmth. With both polarities yang, the bond is active and expansive, driven by initiative — the challenge is making room for pause and listening too. The qualities complete each other: the cardinal initiates, the fixed sustains — one provides the push, the other the staying power, a naturally efficient division of roles.
What they add up to: Aries brings courage, initiative, honesty, enthusiasm and natural leadership, while Leo brings generosity, charisma, creativity, loyalty and confidence. The watch-point is balancing impatience, impulsiveness and difficulty backing down or waiting on one side with pride, a need for approval and drama on the other. With so little baseline friction, the real risk is coasting — it's worth challenging each other to keep the bond alive.
Everything is computed in your browser. Birth dates, times and places are never sent to any server.