Karmic Synastry Calculator

What is karmic synastry?

Synastry is the astrological practice of comparing two birth charts to understand a relationship: one person’s planets are laid over the other person’s chart, and the contacts between them are read as the dynamics of the bond. Karmic synastry narrows that comparison to the contacts that astrological tradition associates with karma, the felt sense that two people did not meet by accident. Where ordinary synastry asks “how do these two get along,” karmic synastry asks “why do these two feel fated.”

The vocabulary of karmic synastry comes mostly from Vedic astrology, and its two central symbols are the lunar nodes. Rahu, the north node, is the point where the Moon’s orbit crosses the ecliptic heading north; Ketu, the south node, is the opposite point, always exactly 180 degrees away. They are not physical bodies but mathematical points, yet in Vedic lore they carry enormous weight: Rahu is associated with worldly hunger, obsession, and the experiences the soul is said to be reaching toward in this life, while Ketu is associated with detachment, past mastery, and what the soul is said to be releasing. When one person’s Rahu or Ketu touches the other person’s Sun, Moon, or planets within a tight orb, tradition reads it as a karmic contact, a thread between the two charts that feels older than the relationship itself.

The other great karmic significator is Saturn. Saturn is the slowest of the traditional seven planets, taking about 29 years to circle the zodiac, and in lore it governs time, duty, limits, and the lessons that cannot be skipped. A hard contact from one person’s Saturn, conjunction, square, or opposition, to the other person’s Sun, Moon, Venus, or Mars is the classic “glue” of karmic synastry: the relationship is said to carry obligations, tests of patience, and a seriousness that keeps the two people working on something together, whether they call it love, family, or business. Two Saturns in hard contact add a generational resonance, two people maturing through the same themes at the same time.

It is worth being honest about what all of this is. The nodes and Saturn are real astronomical points, computed on this page with real orbital mechanics and checked against a published ephemeris. The idea that their contacts mark “karma” belongs to astrology’s symbolic language, transmitted for centuries and still used by working astrologers. This calculator keeps those two layers separate: the astronomy is precise and verifiable, and every interpretation is phrased as traditional lore, “traditionally associated with,” never as a prediction about your relationship. Take what resonates, hold it lightly, and enjoy the precision of the calculation underneath it.

How the karmic intensity score works

Comparing two charts by hand means checking dozens of possible contacts and judging which ones matter. This calculator does that scan for you and reduces it to a single karmic intensity score built from an explicit rubric, the same rubric shown in the tool itself, so you can see exactly where every point comes from.

The rubric scores only the contacts that karmic tradition emphasizes. A nodal contact, one person’s Rahu or Ketu conjunct or opposite the other’s Sun, Moon, Mercury, Venus, Mars, or Saturn within 8 degrees, earns 3 points. These are the headline karmic markers of the lore, the contacts most often described as fated or past-life flavored. A Saturn contact, one person’s Saturn conjunct, square, or opposite the other’s Sun, Moon, Venus, or Mars within 7 degrees, earns 2 points: the binding, lesson-carrying contacts. Saturn-Saturn and node-node hard contacts, conjunction, opposition, or square within 7 degrees, earn 2 points each. Any karmic contact with an orb of 2 degrees or less earns 1 bonus point, because in aspect work a tighter orb traditionally means a louder contact.

Three kinds of contacts are deliberately not scored. Venus-Mars, Moon-Moon, and Sun-Moon conjunctions, oppositions, and trines within 8 degrees are shown as harmony markers worth 0 points: in traditional lore they describe chemistry, comfort, and ease, which are real relationship ingredients but not karmic binding. Jupiter’s contacts are not scanned at all, since Jupiter is traditionally the planet of ease and blessing rather than karmic debt. And squares and trines involving the nodes are not counted, because the nodal lore centers on conjunctions and oppositions to the nodal axis.

The total maps to three bands: 0 to 4 is Gentle, 5 to 9 is Moderate, and 10 or more is Strong. A Gentle score means few traditional karmic markers, which lore reads as a lighter, freer-feeling connection with less sense of obligation. A Moderate score means several markers are present and the relationship is likely to feel significant and lesson-bearing. A Strong score means the charts are densely interlocked in the traditional karmic language. None of these bands predicts whether a relationship will last or be happy; the score tallies traditional markers, and a real relationship is always larger than its chart contacts.

Worked example: two real charts, real numbers

Here is a worked example so you can see exactly what the tool computes. The calculator loads with this pair ready. Person A was born August 25, 1990 at 12:00 in Delhi (UTC+5:30). Person B was born December 1, 1992 at 14:00 in London (UTC+0, since London is on GMT in December).

First, the two sidereal charts. Person A’s chart: Sun in Leo 8.08 degrees, Moon in Libra 4.50 degrees, Mercury in Leo 29.83 degrees, Venus in Cancer 20.17 degrees, Mars in Taurus 3.06 degrees, Jupiter in Cancer 7.72 degrees, Saturn in Sagittarius 25.65 degrees, Rahu in Capricorn 12.22 degrees, Ketu in Cancer 12.22 degrees (Lahiri ayanamsa 23.7263 degrees). Person B’s chart: Sun in Scorpio 15.88 degrees, Moon in Aquarius 8.47 degrees, Mercury in Libra 28.45 degrees, Venus in Sagittarius 27.80 degrees, Mars in Cancer 3.80 degrees, Jupiter in Virgo 16.04 degrees, Saturn in Capricorn 19.87 degrees, Rahu in Scorpio 28.27 degrees, Ketu in Taurus 28.27 degrees (Lahiri ayanamsa 23.7580 degrees).

Now the contact scan. Contact 1: Person A’s Rahu at Capricorn 12.22 degrees sits 7.65 degrees from Person B’s Saturn at Capricorn 19.87 degrees, a conjunction within the 8-degree nodal orb: 3 points. In the lore, the north node on Saturn is read as a fated pull around duty and structure. Contact 2: Person A’s Saturn at Sagittarius 25.65 degrees sits 2.15 degrees from Person B’s Venus at Sagittarius 27.80 degrees, a conjunction within the 7-degree Saturn orb: 2 points, the classic Saturn glue around love and values. Contact 3: Person B’s Saturn at Capricorn 19.87 degrees sits opposite Person A’s Venus at Cancer 20.17 degrees with an orb of just 0.31 degrees: 2 points plus 1 tight-orb bonus point. Notice the symmetry: both Saturns touch the partner’s Venus, A’s Saturn by conjunction and B’s Saturn by opposition, which the lore would read as an unusually strong mutual karmic binding around the Venus themes of love and values.

The total is 3 + 2 + 3 = 8 points, the Moderate band. Alongside the karmic contacts, the tool finds three harmony markers worth 0 points: Person A’s Mars trine Person B’s Venus (orb 5.26 degrees), Person A’s Moon trine Person B’s Moon (orb 3.97 degrees), and Person A’s Sun opposite Person B’s Moon (orb 0.39 degrees), traditionally read as chemistry and emotional attunement running alongside the karmic binding. This is the honest picture the calculator aims for: the score, every orb to two decimals, the traditional reading of each contact, and the harmony shown separately so it is never confused with karma.

Sidereal or tropical: why this calculator uses the Vedic zodiac

There are two zodiacs in common use. The tropical zodiac, used by most Western astrology, is anchored to the seasons: 0 degrees Aries is defined as the March equinox point. The sidereal zodiac, used by Vedic astrology, is anchored to the fixed stars. Because the Earth’s axis precesses like a slow wobble, the equinox point drifts westward along the stars by about 50.29 arcseconds per year, so the two zodiacs are currently about 24.2 degrees apart and the gap keeps growing.

This calculator uses the sidereal zodiac with the Lahiri ayanamsa, the standard of Vedic astrology and of Indian panchangs. The choice is deliberate: karmic synastry is a Vedic-flavored practice, built on Rahu and Ketu, which are Vedic concepts, and on Saturn’s role in the Vedic lore of karma. Reading those contacts in the sidereal zodiac keeps the symbolism and the astronomy in the same tradition. Practically, it means every longitude on this page, planets and nodes alike, has the Lahiri ayanamsa subtracted, about 23.73 degrees for a 1990 birth and about 23.76 degrees for a 1992 birth.

If you normally use Western tropical astrology, expect the signs here to sit roughly one sign earlier than you are used to: a tropical Leo Sun becomes a sidereal Cancer Sun, and so on. The contacts themselves are what matter, and they are computed the same careful way in either zodiac. One honest caveat: the tool uses the mean lunar node, the smoothly regressing average position of the nodes, rather than the true node, which wobbles up to about 1.5 degrees around the mean. Vedic practice traditionally works with the mean node, and the mean node is the stable, verifiable quantity: this engine’s mean node matches a published ephemeris to within 7.2 arcseconds.

Is the karmic synastry calculator free?

Yes. The karmic synastry calculator is completely free, and no account or signup is needed. Enter two birth dates, two birth times, and the two birthplace time zones, and you get the full contact scan: every karmic contact with its exact orb, the karmic intensity score with its band, the harmony markers, and both sidereal charts, computed in your browser with real astronomy. Use the copy button to save the result as plain text, or the print button for a clean printout.

There are no locked features and no “premium orb” upsell: the orbs, the rubric, and the method are all stated openly on the page, because a score you cannot audit is not worth much. If you compare many pairs, for example across a family or a circle of friends, the tool recalculates instantly every time you change an input, so you can explore freely.

Frequently asked questions

What is karmic synastry?

Karmic synastry is the comparison of two birth charts limited to the contacts that astrological tradition associates with karma: nodal contacts (Rahu or Ketu touching the partner’s Sun, Moon, Mercury, Venus, Mars, or Saturn), hard Saturn contacts to personal planets, and Saturn-Saturn or node-node contacts. Where ordinary synastry asks how two people get along, karmic synastry asks why the meeting feels fated.

Is the karmic intensity score a prediction?

No. The karmic intensity score is this tool’s own tally of traditional karmic markers: 3 points per nodal contact, 2 per Saturn contact, 2 per Saturn-Saturn or node-node contact, plus 1 for tight orbs of 2 degrees or less, with bands at 0-4 Gentle, 5-9 Moderate, and 10+ Strong. It scores the markers astrological tradition associates with karmic themes; it does not predict whether a relationship will last or be happy.

Which karmic contacts matter most?

In traditional lore the heaviest contacts are nodal contacts with the Sun or Moon (3 points each in this calculator’s rubric), because the luminaries are the most personal points, and tight Saturn oppositions or conjunctions to Venus or the Moon, the classic binding contacts. The tight-orb bonus exists for exactly this reason: a Saturn-Venus opposition at 0.31 degrees, like the one in this page’s worked example, traditionally counts louder than the same aspect at 6 degrees.

Does this calculator use sidereal or tropical positions?

Sidereal, using the Lahiri ayanamsa, the standard of Vedic astrology. Karmic synastry is built on Rahu and Ketu, which are Vedic concepts, so the calculator keeps the symbolism and the astronomy in the same tradition. Every longitude shown, planets and nodes alike, has the Lahiri ayanamsa (about 24.2 degrees in 2026) subtracted from the tropical position.

Why do you need both birth times?

Because the Moon moves about 13.2 degrees per day, roughly 0.55 degrees per hour, so a wrong or missing birth time shifts every Moon contact and can add or remove karmic contacts, changing the score. The nodes move only about 3 arcminutes per day, so node positions are nearly time-independent, but any contact involving the Moon depends directly on birth-time accuracy.

What is the difference between a Rahu contact and a Ketu contact?

Rahu is the north (ascending) lunar node and Ketu is the south (descending) node, always 180 degrees apart. In traditional lore a Rahu contact with a partner’s planet is read as a fated, magnetic pull toward new experiences around that planet’s themes, while a Ketu contact is read as a familiar, past-life resonance, a sense of having met before. This calculator scores both at 3 points and names which node is involved.

Is the karmic synastry calculator free?

Yes, it is completely free and no account or signup is needed. Enter two birth dates, two birth times, and the two birthplace time zones to get every karmic contact with exact orbs, the karmic intensity score, the harmony markers, and both sidereal charts. Use the copy button to save the result as plain text.

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About the author

This karmic synastry calculator was built by the ZodiaScope editorial team. We publish astronomy-accurate astrology tools alongside traditional interpretations: the planetary longitudes on this page are computed from Keplerian orbital elements with lunar and Jupiter/Saturn perturbation terms, the mean lunar node comes from the Moon’s orbital elements, everything is converted to the sidereal zodiac with the Lahiri ayanamsa, and the engine is verified against a published ephemeris, while the karmic readings follow traditional astrological lore. Our interpretations are offered for reflection and entertainment.

Published: October 20, 2026. Last updated: October 20, 2026.