Birth Chart Synastry
Compare two birth charts to generate a free synastry chart. Review your synastry aspects, orbs, house overlays, and relationship patterns, then use optional AI interpretation to understand the strongest attraction, communication, pressure, and long-term growth themes.
This birth chart synastry tool helps you compare two birth profiles, generate a synastry chart, and add an optional shared city for relocated house overlays.
Enter the birth date, birth time, and birth location for both people to create a two-person synastry chart. This calculator compares two natal charts and shows how your planets, houses, and angles interact.
Accurate birth times make the ascendant, houses, and house overlays more reliable. If you do not know the exact birth time, you can still compare the main planetary aspects, but house-based interpretation should be read with more caution.
You can also add a shared city. A shared city does not change the natal aspects between two charts, but it can change relocated ascendants and relocated house overlays. This helps you explore the relationship’s house emphasis for one specific location.
Overview
This free synastry chart calculator helps you compare two birth charts in one workflow. You can generate a synastry chart, review the closest inter-chart aspects by orb, see house overlays, and explore optional shared-city relocated overlays.
After the chart is calculated, AI can help interpret the same data. It does not replace the calculator, recalculate the chart, or turn the relationship into a score. Instead, it helps you understand which relationship patterns stand out most and how attraction, communication, emotional connection, pressure points, and long-term growth themes may appear in the chart.
Relationship Astrology Tool
A synastry chart is a relationship astrology chart that compares two people’s natal charts. It shows how one person’s planets connect with the other person’s planets, which contacts are closest by orb, and where one person’s planets fall in the other person’s houses.
This page is built for people who want more than a simple Sun-sign match. Instead of saying whether two people are “compatible” in one number, it gives you the chart data first: the bi-wheel chart, the aspect table, house overlays, and optional shared-city overlays.
The optional AI interpretation comes after the chart is calculated. That matters because the AI is not guessing from a generic relationship prompt. It reads the synastry data generated on this page and helps organize the strongest relationship patterns into a clearer reading.
Synastry Chart Results
Your synastry chart compares two natal charts side by side. It highlights where the planets connect, which aspects are closest by orb, where attraction or emotional connection may appear, and where tension, misunderstanding, or growth patterns may show up.
Planetary aspects show how one person’s planets connect with the other person’s planets. You can review conjunctions, trines, sextiles, squares, and oppositions, along with the orb for each contact. A smaller orb usually means the aspect is tighter and more important to read first.
House overlays show where one person’s planets fall in the other person’s chart. This can describe which life areas the relationship activates, such as romance, communication, intimacy, daily life, responsibility, family patterns, or long-term growth.
A single aspect does not define a relationship. A useful synastry reading looks for repeated themes across close aspects, personal planets, Saturn or Pluto contacts, and house overlays. These patterns can show what feels easy, what feels intense, and what needs care.
If you add a shared city, the calculator can show relocated ascendants and relocated house overlays for that location. This does not rank cities or predict outcomes. It helps you see how the house emphasis may shift when both people are considered in the same place.
If your relationship question involves distance, travel, relocation, or living in the same city, the map view adds location context. The synastry chart remains the main relationship comparison, while the astrocartography map gives each person’s broader location background.
AI Interpretation
After you calculate your synastry chart, you can ask AI to interpret the chart you just generated. This is the main difference between a static synastry calculator and an AI-assisted synastry chart reading.
The AI uses the calculated synastry data shown on this page: birth details, ascendants, planet signs, whole-sign houses, inter-chart aspects, aspect orbs, house overlays, and optional shared-city relocated overlays. It can help identify the strongest contacts by orb, summarize attraction and emotional connection patterns, explain communication friction, point out pressure points, and describe what supports long-term growth.
This does not mean AI knows what someone feels, predicts whether a relationship will last, or decides whether two people should be together. The goal is more practical: turn the chart data into relationship questions you can actually reflect on.
Location-Aware Synastry
Most synastry charts compare two natal charts only from the original birth locations. AstroCarto adds an optional shared-city layer.
When you enter a shared city, the calculator can show both people’s relocated ascendants and relocated house overlays for the same location. The natal inter-planet aspects do not change with location, but houses and ascendants can. That means the shared city does not rewrite the relationship; it highlights how the relationship’s house emphasis may feel in that place.
Use this feature when you want to explore questions such as: What life areas do we activate for each other in this city? Does this location emphasize partnership, home, daily routines, work, intimacy, or long-term responsibility? How does the relationship feel when both charts are placed in the same geographic context?
This is not a best-city ranking, a relocation verdict, or a full astrocartography line reading. It is a focused shared-city overlay for the synastry chart you calculated.
Synastry Basics
Birth chart synastry and natal chart synastry usually mean the same thing: comparing two people’s natal charts to understand how their planets, houses, and angles interact.
This goes beyond Sun-sign compatibility. A synastry chart can include the Moon for emotional needs, Venus and Mars for attraction and desire, Mercury for communication, Saturn for commitment or pressure, and Pluto for intensity or deeper transformation when those factors appear in the chart.
On this page, birth chart synastry, natal chart synastry, and free synastry chart results all point to the same workflow: enter two birth profiles, calculate the chart, review the aspects and overlays, and use optional AI interpretation to understand the strongest relationship patterns.
Reading Guide
The orb shows how close an aspect is. Smaller orbs usually deserve more attention because the connection is tighter and easier to notice.
The Sun, Moon, Venus, Mars, and Mercury often describe identity, emotional needs, affection, desire, and communication. These are usually the first planets to review in birth chart synastry.
Saturn contacts can describe responsibility, commitment, limits, distance, or pressure. Pluto contacts may describe intensity, control themes, or deep transformation. These themes should be read carefully, not fatalistically.
House overlays show where one person lands in the other person’s life. They can highlight romance, intimacy, friendship, home, work, daily habits, creativity, or long-term responsibility.
One aspect does not define a relationship. A useful synastry chart interpretation combines aspects, orbs, houses, and repeated themes instead of reducing the relationship to a single score.
Clear Boundaries
AI can help you understand the relationship patterns shown in the calculated chart. It can explain close aspects, attraction signatures, emotional connection themes, communication friction, pressure points, growth areas, house overlays, and optional shared-city relocated overlays.
AI cannot know someone’s private feelings, predict marriage or breakup, guarantee reconciliation, detect cheating, or decide whether you should stay together. It also does not invent missing astrology data, interpret composite charts, progressed synastry, asteroids, transits, or timing windows on this page.
Use the AI reading as a reflection tool, not as a relationship verdict.
FAQ
A synastry chart is a relationship astrology chart that compares two people’s natal charts. It shows planetary aspects, house overlays, and other chart connections that may describe attraction, emotional patterns, communication style, pressure points, and relationship dynamics.
Yes. You can generate a free synastry chart and review the main chart results, including the chart wheel, aspect table, and house overlays. Some deeper interpretation features, such as AI-generated relationship insights, may require login or credits.
Yes. Birth chart synastry and natal chart synastry usually refer to the same method: comparing two birth charts to understand how two people’s planets, houses, and angles interact.
A synastry chart with interpretation explains the strongest contacts between two charts. It may include emotional connection, Venus-Mars attraction, Mercury communication themes, Saturn pressure or commitment themes, Pluto intensity, and house overlays.
Yes. The free chart results can be used as a starting point for synastry analysis. The aspect table, chart wheel, and house overlays help you identify the strongest relationship patterns before using deeper AI interpretation.
No. Synastry is more useful as a pattern-reading tool than a score. This calculator shows relationship dynamics in the chart, but it does not decide whether two people should be together.
No. AI does not predict marriage, breakup, reconciliation, cheating, pregnancy, or private feelings. It only explains the synastry data calculated on this page.
An exact birth time is recommended because it affects the ascendant, houses, and house overlays. If you do not know the exact time, you can still compare the main planetary aspects, but house-based interpretation may be less precise.
No. This page focuses on standard natal chart synastry: two birth charts, major inter-chart aspects, house overlays, and optional shared-city relocated overlays. Asteroids, progressed synastry, composite charts, transits, and timing techniques are separate methods.
The shared city option adds relocated ascendants and relocated house overlays for one location. It helps you explore how the relationship’s house emphasis may feel in a specific place. It is not a best-city ranking and does not replace a full astrocartography map reading.
Enter both birth profiles above to compare two natal charts, review the closest aspects, and explore the relationship patterns shown in your synastry chart. After the free chart is calculated, you can use optional AI interpretation to turn the results into a clearer relationship reading.