Rahu Ketu Calculator
Find your natal Rahu (north node) and Ketu (south node) from your birth date. The tool computes the mean lunar node astronomically, then gives each node’s sign, degrees, nakshatra and pada in Lahiri sidereal or tropical zodiac.
Uses the mean lunar node. The true node can differ by up to about 1.5 degrees; for chart-critical precision use a full ephemeris. For entertainment and study.
Worked example, checked against this exact tool
Birth date 15 June 1990, Lahiri sidereal: Rahu = Capricorn 15.97°, Shravana pada 2; Ketu = Cancer 15.97°, Pushya pada 4. This matches the historical record: the mean node sat in sidereal Capricorn from late September 1989 to mid-April 1991. Switch to tropical and the same birth gives Rahu in Aquarius 9.69°, the ayanamsa difference made visible.
What Rahu and Ketu are
Rahu and Ketu are the two lunar nodes: the points where the Moon’s path crosses the Sun’s path (the ecliptic). They are mathematical points, not physical planets, which is why tradition calls them shadow planets (Chhaya Grahas). Eclipses can only happen near them. They are locked exactly 180 degrees apart and move backward (retrograde) through the zodiac, completing a full cycle in about 18.6 years, roughly 18 months per sign.
How the calculation works
The tool computes the Julian day of your birth, then the mean longitude of the Moon’s ascending node with the standard astronomical formula: Ω = 125.04452° − 1934.136261° × T, where T is Julian centuries from J2000. That gives the tropical position of Rahu. For the Vedic sidereal reading, the Lahiri ayanamsa (about 24.2° today, growing slowly) is subtracted. Ketu is simply Rahu + 180°. The nakshatra is the 13°20′ lunar mansion containing the node; the pada is which quarter of it.
Mean node vs true node
This calculator uses the mean node, which moves smoothly backward. The true node wobbles slightly as the Moon’s orbit is perturbed, differing by up to about 1.5 degrees. Most transit calendars (including the December 5, 2026 Rahu-into-Capricorn ingress this tool reproduces exactly) use the mean node, so the two agree on sign placements except very near sign boundaries.
What competing calculators miss
The main rival needs your birth time and birthplace and runs a full ephemeris, which is precise but heavy. Transit-only tools tell you where the nodes are now, not where they were when you were born. This calculator needs only your birth date, shows both zodiac systems side by side, and documents its formula so you can verify it.
Frequently asked questions
How do I find my Rahu and Ketu sign?
Enter your birth date above. The tool computes the lunar nodes’ positions: Rahu’s sign and degrees, with Ketu exactly opposite.
What is the difference between Rahu and Ketu?
Rahu (north node) is associated with ambition, appetite and the unconventional; Ketu (south node) with detachment, the past and the spiritual. They form one axis, so whatever Rahu intensifies in one area of life, Ketu loosens in the opposite area.
Why are Rahu and Ketu always opposite?
They are the two points where the Moon’s orbit crosses the ecliptic, which are geometrically opposite each other by definition.
What is a nakshatra and pada?
A nakshatra is one of 27 lunar mansions (13°20′ each) dividing the zodiac. Each nakshatra has four padas (quarters) of 3°20′ each, used for finer interpretation.
Should I use sidereal or tropical?
Vedic astrology uses sidereal (Lahiri ayanamsa); Western astrology uses tropical. They currently differ by about 24.2 degrees.
How long do Rahu and Ketu stay in one sign?
About 18 months per sign, completing the zodiac in roughly 18.6 years.
What does it mean when Rahu transits my Moon sign?
Tradition reads nodal transits over the natal Moon (or ascendant) as periods of noticeable shifts in life themes, since the transit activates that house axis of the chart.
How accurate is the mean node?
Within about 1.5 degrees of the true node. Sign placements agree except very near ingress dates; this tool reproduces the published mean-node ingress dates exactly.
Do I need my birth time?
Not for the nodes: they move only about 3 arc-minutes per day, so the date alone determines the sign. Birth time matters for houses and the ascendant, which this tool does not compute.
Is this the same as my Moon sign?
No. Your Moon sign (Janma Rashi) is where the Moon was; Rahu/Ketu are the lunar nodes, independent points. Transit readings are often done from the Moon sign, which is a separate calculation.