Zodiac compatibility calculator
Every zodiac sign has an element and a modality.
This calculator reads the element, modality, and polarity of the two signs, taken from your full birth dates or picked directly, and combines them into one score out of 100. The formula is published below, every factor is shown next to the result, and the same two dates always produce the same number. Dates never leave your browser.
How to use it
Enter the first birth date
Use the full date: day, month, and year. The form checks the whole date and will reject an incomplete one, even though the sign itself comes only from the day and month.
Enter the second birth date
Add the other person's full date. The order of the two fields does not matter, because the score is computed from the pair of signs, not from one person being listed first.
Press Calculate
The tool converts each full date to a zodiac sign using fixed tropical boundaries, then calculates three values: element, modality, and polarity.
Read the breakdown
Every factor and its number appear with the result, so you can see exactly which combination produced the total score.
Share the card
Build an image of the result and share it. The card is drawn in your browser, and the dates never enter a link or a server.
How zodiac compatibility is calculated
Each full birth date is first converted to a zodiac sign using fixed tropical boundaries. If you already know both signs, you can choose them instead of the dates; this step is then skipped, and everything after it is the same. The boundaries are set by day and month only, without a year adjustment, so the actual moment the Sun changes sign can shift by about a day from year to year.
This page accepts that simplification and names it: the same date always maps to the same sign here. After both signs are known, three values are added. Elements: the same element gives 44; compatible elements are fire with air and earth with water, worth 38; neutral elements are fire with earth and air with water, worth 22; conflicting elements are fire with water and earth with air, worth 10.
Modalities: different modalities give 26, the same modality gives 16. Polarity: matching polarity gives 30, non-matching gives 12. The total is the sum of those three numbers.
The highest possible score is exactly 100, and the lowest is 38. Polarity follows from element in the tropical system, so the third factor is not independent of the first; the breakdown shows all three terms but does not present them as separate pieces of evidence. Nothing in the calculation is random: the same two dates return the same number every time.
Questions people ask
How is zodiac compatibility calculated here?
Each of your two full birth dates is converted to a zodiac sign using fixed tropical date boundaries. If you pick the two signs instead of dates, this step is skipped. Then three factors are measured for the pair: element, modality, and polarity, with the point values shown in the formula above. The three are added into a single number from 38 to 100. Nothing is hidden and nothing is random.
Which sign do I get if I was born on a cusp date?
This tool uses fixed boundaries by day and month, without a year adjustment. The real moment the Sun enters a sign can shift by about a day from year to year, so a person born near a boundary may be a different sign in a full ephemeris. Here you get the sign the fixed table assigns to that date, and the page tells you that plainly.
Does the order of the two dates matter?
No. The three factors—element, modality, and polarity—describe the pair of signs as a pair. They are the same whether you enter one date first or the other. Swapping the fields never changes the number.
Is this the same as a full birth chart reading?
No. A full birth chart plots the Sun, Moon, planets, houses, and aspects for an exact time and place. This calculator only takes one tropical zodiac sign per person, from the day and month or as you pick it, then scores the pair by element, modality, and polarity. It is a fixed arithmetic game on two signs, not an interpretation of individual charts or a prediction about the relationship.
How is this different from the birthday compatibility tool?
The birthday compatibility tool works from the two full dates themselves and builds its score from a different published formula. This zodiac page scores only the pair of signs, converted from the dates or picked directly, by element, modality, and polarity. They are separate games with separate arithmetic; neither reads personal details.
Are our birth dates stored anywhere?
No. The calculation runs entirely in your browser, so the dates are never sent to a server. They are not written into the address bar or saved on your device. If you build a share card, the image is drawn locally and the share link contains no date data. Closing the tab leaves nothing behind.
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