Ayanamsa Converter
Compare KP New, KP Old, Lahiri, and Raman ayanamsa values for any date — and convert tropical to sidereal longitudes.
What is Ayanamsa?
Ayanamsa is the offset between the tropical zodiac (defined by the equinoxes, used in Western astrology) and the sidereal zodiac (defined by the fixed stars, used in Vedic and KP astrology). The two zodiacs drift apart by roughly 50.3 arcseconds per year due to the precession of the equinoxes. As of 2026, the offset is approximately 24°10' — meaning a planet at 0° tropical Aries actually sits at about 5°50' sidereal Pisces.
To compute a sidereal chart, you subtract the ayanamsa from the tropical longitude. The choice of which ayanamsa to use is what distinguishes the major Indian astrology systems.
The Four Major Ayanamsa Systems
- KP New — modern Krishnamurti Paddhati ayanamsa, derived from a base offset of 1335.7 arcseconds at epoch 1900. The KP system's authoritative reference. Slightly larger than KP Old.
- KP Old (Krishnamurti) — original Krishnamurti ayanamsa, base offset 1320 arcseconds. Used in older KP texts and software. The Swiss Ephemeris constant for this is
SE_SIDM_KRISHNAMURTI. - Lahiri (Chitrapaksha) — the Indian government-recognised standard, named after N.C. Lahiri. Anchored to the star Spica (Chitra) at 180° sidereal. Used by most mainstream Vedic software. The largest of the four values typically.
- Raman — proposed by B.V. Raman in the early-20th century. Approximately 22 arcminutes smaller than Lahiri. Less common today but still used by some traditional Vedic astrologers.
For any given date, all four values are within about half a degree of each other — but that half-degree is enough to push a planet across a sub-lord boundary, change a nakshatra pada, or shift an event window by a measurable interval. The choice of ayanamsa is therefore not cosmetic — it is the foundation under every prediction.
How to Use the Converter
- Compare ayanamsa values for a chart's birth date — input the date and see all four. Check which value your chart software is using by comparing it to the result.
- Convert a tropical longitude to sidereal — input the date plus a tropical longitude, and the tool returns the sidereal equivalent under each system. Useful for cross-referencing between Western and Indian charts.
- Verify ayanamsa drift over time — try the same longitude with dates 50 years apart to see how much the ayanamsa has shifted.
Frequently Asked Questions
Which ayanamsa should I use for KP astrology?
KP New is the standard for modern KP work. The original Krishnamurti texts used what is now called KP Old (base 1320 arcsec). Most contemporary KP software, including this site's calculations, defaults to KP New. The difference between them is small (about 15 arcseconds at any given moment) but meaningful at sub-lord boundaries.
Why does the ayanamsa value change over time?
The Earth's axis precesses (wobbles) on a roughly 26,000-year cycle. The tropical zodiac rotates with the equinoxes; the sidereal zodiac is fixed to the stars. As precession proceeds, the gap between them grows by about 50.3 arcseconds per year, or roughly 1° every 72 years. The ayanamsa value therefore increases monotonically — about 24°10' in 2026, was about 23°35' in 1980, will be about 25°00' in 2090.
Why are KP New and Lahiri different by such a small amount?
Both are anchored to similar empirical references — Lahiri to Spica at 180°, KP New to a related fixed-star calibration. The difference (typically 4-6 arcminutes) reflects slightly different astronomical assumptions about the rate of precession and the calibration epoch. Practically: a Lahiri chart and a KP New chart for the same person will look identical at the sign and house level, but sub-lord allocations near boundaries can differ.
Can I convert from a Lahiri chart to a KP New chart?
Yes — use the converter to find both ayanamsa values for the chart's birth moment, then add the difference to each Lahiri sidereal longitude to get the KP New value (or vice versa). For example, if Lahiri = 24°10' and KP New = 24°06', the difference is 4 arcminutes — subtract that from each Lahiri longitude to get KP New.
Does Swiss Ephemeris compute these natively?
Yes. Swiss Ephemeris (the reference astronomical library) supports all four through its sidereal-mode constants: SE_SIDM_LAHIRI, SE_SIDM_RAMAN, SE_SIDM_KRISHNAMURTI, and SE_SIDM_KP_NEW. Our converter uses Swiss Ephemeris where available and falls back to the canonical formulas otherwise.
Related Tools and Reading
- Free KP Birth Chart Calculator — full chart computed with KP New ayanamsa.
- Sub-Lord Finder — once you have the sidereal longitude, look up the sub-lord.
- What is KP Astrology? — explains how KP New differs from older ayanamsa systems.
Need More Than Ayanamsa Values?
The converter gives you the offset. The full chart calculator gives you the chart. The AI Deep Dive interprets it. Free account: 2 lifetime AI readings, no card required.