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. Kundli Studio 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.
How to read the result
Pick D-16_shodasamsa in the menu that heads any of the six cells on the divisional-charts screen; that menu lists every varga by the engine's own key, sorted by D-number. Each box carries a small figure for its sign — 1 is Aries, 12 is Pisces — and As marks the D16 ascendant. Houses start again from that box: Narasimha Rao's textbook observes that the 4th house from lagna in the D16 may mean something other than the 4th in the D24.
Parasara's list of uses (BPHS 7.1-8) gives this varga benefits and adversities through conveyances, and Narasimha Rao groups the D16 with the D20 and D24 as charts of the mental plane. 'Crux of Vedic Astrology' ties the two together: sixteen is twelve plus four, so the Kalamsa is a second cycle of the fourth house, one that touches the conscious mental plane.
Hovering over a token gives its D16 sign and a degree — sixteen times its degree inside the D1 sign, with multiples of thirty removed — so 0 marks the start of the token's sixteenth-part and 30 its end. Rahu and Ketu share one box in every D16, since the engine sets Ketu exactly opposite Rahu and opposite signs share the same movable, fixed or dual seed. The amber labels, AL through A11 and UL, are arudha padas recalculated from the D16's own placements, so they need not match the D1's.
Key terms
- Kalamsa
- The D16's other name; Narasimha Rao's lesson notes tie it to the Moon's sixteen kalas, or phases, and read it for what relieves the mind and what troubles it.
- Mental plane
- Narasimha Rao's band for the D16, D20 and D24, read for matters of mind and intellect, between the physical charts D1 to D12 and the sub-conscious D27 and D30.
- Second cycle
- 'Crux of Vedic Astrology' reads sixteen as twelve plus four: the D16 as a further round of the fourth house, dealing with movable possessions such as vehicles.
- A4 (Matri Pada)
- The arudha of the 4th house, in amber; Narasimha Rao's lesson notes cite the A4 of the D16 as their example of an arudha read inside a divisional chart.
- As
- The D16 ascendant: the sign the rising degree reaches after division. The North Indian drawing puts it in the top centre box as house 1.
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
The parts sit at the same multiples of 1 degree 52 minutes 30 seconds in every sign; the sign's quality only sets where the count starts, 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.
Which house of the D16 chart is read for vehicles?
Worked examples in the library take the 4th house counted from the D16 ascendant as the house of vehicles and read the chart from there. Narasimha Rao's lesson notes add the D16's A4, the arudha of that house, as an example of reading arudhas inside a divisional chart.