Just for fun
Zodiac Love Compatibility
Enter two birthdays, or pick two signs, and see what the stars say about your match. It runs in your browser and nothing you enter leaves it.
Your birthday
The year is optional: a sun sign only needs the day and the month.
Their birthday
The year is optional: a sun sign only needs the day and the month.
Birthdays never leave your browser. Nothing is saved or sent.
How zodiac compatibility works
Zodiac compatibility compares the Western sun signs of two people. Your sun sign comes from the day you were born: the Sun spends about a month in each of the twelve signs, so a birthday on 21 July makes you a Cancer and one on 23 July a Leo. This calculator only needs the day and the month, or you can pick a sign directly if that is all you know.
Fire, earth, air and water
Each sign belongs to one of four elements. Fire signs (Aries, Leo, Sagittarius) are energetic and enthusiastic, earth signs (Taurus, Virgo, Capricorn) are practical and steady, air signs (Gemini, Libra, Aquarius) are curious and talkative, and water signs (Cancer, Scorpio, Pisces) are intuitive and emotional. Traditionally fire and air get along, and so do earth and water; fire with water, or earth with air, ask for more patience.
Cardinal, fixed and mutable
Signs also come in three modalities, or ways of acting. Cardinal signs start things, fixed signs keep them going and mutable signs adapt along the way. Two different modalities tend to complement each other, while two of the same can share a rhythm and a stubborn streak.
The angle between your signs
The twelve signs sit around a wheel, so any two signs make an angle. Signs 60° apart form a sextile, 120° a trine (the most harmonious), 90° a square (friction that can motivate), 180° an opposition (opposites that attract) and 150° a quincunx (an odd couple). Neighbouring signs, 30° apart, form a semi-sextile, and the same sign twice is a conjunction.
How the percentage is made
The percentage adds up points for the element pairing, the modality pairing and the angle, plus a tiny nudge so pairs with the same pattern do not all get the same number. It is always between 30 and 99, and it is the same for the same two signs in either order.
What it can’t tell you
A sun sign is only one slice of an astrology chart, which also has a Moon, Venus, Mars and a rising sign, and none of it is scientific evidence about real relationships. Treat the result as a conversation starter. Kindness, honesty and how you handle disagreements matter far more than any sign. These are Western tropical sun signs; Vedic astrology uses a different system and can give a different sign.
Zodiac compatibility questions
How does the zodiac compatibility calculator work?
It finds each person’s Western sun sign from the birthday (or the sign you pick), then scores the pair from their elements, their modalities and the angle between the signs. Only the day and the month matter, and the same two signs always give the same result in either order.
Is zodiac compatibility accurate?
No, it is entertainment. Astrology is a tradition, not a science, and a sun sign is only one small part of a chart. Use the percentage as a fun conversation starter, not as a verdict on a real relationship.
Do you store my birthday?
No. Everything is calculated in your browser. The birthdays are not sent anywhere, not saved and not put in the page address, and closing the tab forgets them.
Which sign should I use if I was born on the cusp?
Sign dates shift by a day depending on the year and the exact time of birth. If your birthday falls on the first or last day of a sign, try the neighbouring sign too, or pick the sign you identify with.
Which zodiac signs are the most compatible?
Traditionally, signs of the same element or complementary elements (fire with air, earth with water) and signs at a trine or sextile score highest, for example Aries and Leo or Taurus and Virgo. Any pairing can work, though: how two people treat each other counts more than their signs.