D16 Chart Calculator (Shodasamsa)
A free D16 shodasamsa calculator — sixteen parts of 1 degree 52 minutes 30 seconds per sign, each graha placed by exact longitude.
The shodasamsa, or D16, cuts each 30-degree sign into sixteen equal parts of 1 degree 52 minutes 30 seconds — 6,750 arcseconds exactly, so no boundary falls mid-second. It is also called the Kalamsa, and often spelled shodashamsa. Traditionally it is the varga consulted for vehicles, luxuries, comforts and inner happiness. Jagannatha Hora derives every boundary from astronomical longitudes rather than a printed table.
The run of sixteen begins from Aries in a movable sign, Leo in a fixed sign and Sagittarius in a dual sign, then advances one sign per part. Divisions seeded this way do not all agree: the D16 and the D45 seed a fixed sign from Leo and a dual sign from Sagittarius, while the D8 and the D20 swap those two. Enter a birth date, time and place to draw the D16 beside the rasi chart.
The sixteen shodasamsas of Gemini
Gemini is a dual sign, so its sixteen parts run from Sagittarius. In a sample chart for 1 January 1990, noon IST at Chennai — fabricated birth data, used only to show the arithmetic — Jupiter sits at 11 degrees 27 minutes of Gemini.
| Part | Arc within Gemini | Shodasamsa sign |
|---|---|---|
| 1 | 0 deg 00' - 1 deg 52' 30" | Sagittarius |
| 2 | 1 deg 52' 30" - 3 deg 45' | Capricorn |
| 3 | 3 deg 45' - 5 deg 37' 30" | Aquarius |
| 4 | 5 deg 37' 30" - 7 deg 30' | Pisces |
| 5 | 7 deg 30' - 9 deg 22' 30" | Aries |
| 6 | 9 deg 22' 30" - 11 deg 15' | Taurus |
| 7 | 11 deg 15' - 13 deg 07' 30" | Gemini |
| 8 | 13 deg 07' 30" - 15 deg 00' | Cancer |
| 9 | 15 deg 00' - 16 deg 52' 30" | Leo |
| 10 | 16 deg 52' 30" - 18 deg 45' | Virgo |
| 11 | 18 deg 45' - 20 deg 37' 30" | Libra |
| 12 | 20 deg 37' 30" - 22 deg 30' | Scorpio |
| 13 | 22 deg 30' - 30 deg 00' (parts 13 to 16) | Sagittarius to Pisces again |
11 degrees 27 minutes falls in the seventh part, 11 degrees 15 minutes to 13 degrees 07 minutes 30 seconds, so Jupiter's shodasamsa sign is Gemini itself. Parts 13 to 16 repeat Sagittarius, Capricorn, Aquarius and Pisces, because twelve signs on from the seed is the seed again.
Weighted 2 of 20 in Vimsopaka
In the sixteen-fold Shodasavarga weighting the D16 carries 2 of 20 Vimsopaka points — four times the 0.5 given to nine of those sixteen charts, and the fourth-largest of the set behind the D60 (4), D1 (3.5) and D9 (3).
Seeded by movable, fixed or dual
Each part boundary is computed from the sign's quality rather than looked up, so a planet a few arcseconds either side of a boundary still lands in the correct shodasamsa.
One of the ten Dasavarga charts
The D16 is one of the ten Dasavarga divisions — D1, D2, D3, D7, D9, D10, D12, D16, D30 and D60 — weighed alongside the other nine there.
Common questions
What is the D16 chart?
The D16, or shodasamsa, is the divisional chart that cuts every sign into sixteen parts of 1 degree 52 minutes 30 seconds. It is classically named the Kalamsa, and the classical texts consult it for vehicles, luxuries, comforts and inner happiness.
How is the shodasamsa calculated?
Divide the degrees a planet holds within its sign by 1.875 and round down; that index, 0 to 15, counts signs forward from the seed — Aries for a movable sign, Leo for a fixed sign, Sagittarius for a dual sign.
Why do the last four shodasamsas repeat the first four signs?
Because sixteen parts are counted around a twelve-sign zodiac. Parts 13 to 16 stand twelve to fifteen signs beyond the seed, and twelve signs is a full circuit, so they land on the same four signs as parts 1 to 4.
Do I need my exact birth time?
Yes. A shodasamsa part is only 1 degree 52 minutes 30 seconds wide — roughly seven or eight minutes of ascendant travel on average, faster or slower with latitude and the rising sign — so a time out by a quarter of an hour can shift the D16 ascendant.