D30 Chart Calculator (Trimsamsa)

Five unequal bands

In odd signs the bands run: 0° to 5° Mars, giving Aries; 5° to 10° Saturn, giving Aquarius; 10° to 18° Jupiter, giving Sagittarius; 18° to 25° Mercury, giving Gemini; 25° to 30° Venus, giving Libra. Each lord gives the odd sign it owns.

In even signs the five lords come in reverse order and give their even signs: 0° to 5° Venus, Taurus; 5° to 12° Mercury, Virgo; 12° to 20° Jupiter, Pisces; 20° to 25° Saturn, Capricorn; 25° to 30° Mars, Scorpio. The widths reverse too, so Jupiter's band is always the eight-degree one and sits in the middle either way.

Only ten signs can ever appear, and the trimsamsa sign tells you its lord at a glance. The degree printed in the chart is the body's degree in its sign multiplied by thirty, the convention the calculation uses; the band, not the degree, decides the sign.

Why the texts consult it

In the classical text, the chapter on the uses of the vargas assigns the trimsamsa to evils, meaning the difficulties a life meets. Later practice reads it for character under pressure and for health and hardship themes, and some readers use it to judge how much weight a planet's other placements can carry.

On this page that remains an attribution. The trimsamsa does not report what will happen to anyone. It shows which planet rules the band each body falls in and where that places the body, and a careful reading puts it next to the birth chart, the navamsa and the dashas before saying anything at all.

The 1961 trimsamsa, band by band

Begin with the 1961 ascendant: 11°23′ of an even sign, Scorpio, which is its second band, 5° to 12°, ruled by Mercury, so the D30 lagna is Virgo. Three planets past 25° of Scorpio — Sun, Mars, Mercury — are in the Mars band and keep Scorpio. The nodes join them: each is 27°41′ into an even sign, again Mars's band.

Venus (16°33′ of Scorpio) and Jupiter (13°07′ of Capricorn) fall in the eight-degree Jupiter band of even signs and go to Pisces. Saturn, just 4°17′ into Capricorn, is in the opening Venus band and goes to Taurus. The Moon, early in an odd sign at 3°18′ of Aquarius, is in the first, Mars-ruled band and goes to Aries.

Counted from the Virgo lagna, Scorpio is the third house and holds five bodies; Pisces, the seventh, holds Venus and Jupiter; Taurus, the ninth, holds Saturn; and Aries, the eighth, holds the Moon. Mars rules the band of six of the ten points in this chart, a fact the lords table shows at once.

Narrow margins in the example

Unequal bands put the boundaries in unfamiliar places, so it pays to check them. Mercury, at 25°34′, is barely half a degree into the Mars band. Jupiter, at 13°07′, has crossed the 12° line by just over a degree; Saturn, at 4°17′, is about three quarters of a degree short of the 5° line that would hand it to Mercury and Virgo.

The lagna, at 11°23′, is just over half a degree from the 12° line; a slightly later birth would move the D30 lagna from Virgo to Pisces and re-count every house. The trimsamsa therefore needs a well-recorded birth time before its houses mean much.

The lords table

Under the chart the page lists each body with its birth position, its trimsamsa lord and its D30 sign. The lord is recomputed from the bands above and shown only where it gives the same sign as the chart; if the two ever disagreed for a body, that row would show a dash rather than two different answers.

Only the classical nine and the ascendant are banded; the outer planets are absent. The trimsamsa adds a layer to the natal reading and is never the whole of it, and it carries no timing of its own — that comes from the dashas. A crowded or awkward-looking trimsamsa is a description of where the texts direct attention and nothing more; the birth chart, the navamsa and the running periods decide what, if anything, it means for a life.

How is the trimsamsa chart calculated?

Find which of five bands a body's degree falls in. In odd signs: Mars 0–5°, Saturn 5–10°, Jupiter 10–18°, Mercury 18–25°, Venus 25–30°, giving Aries, Aquarius, Sagittarius, Gemini, Libra. In even signs: Venus 0–5°, Mercury 5–12°, Jupiter 12–20°, Saturn 20–25°, Mars 25–30°, giving Taurus, Virgo, Pisces, Capricorn, Scorpio.

Why are Cancer and Leo never in a D30 chart?

Because the Sun and the Moon rule none of the five bands. Each band sends a body to a sign owned by its lord, and the lords are Mars, Saturn, Jupiter, Mercury and Venus, so only their ten signs can appear.

What does the trimsamsa show?

Brihat Parasara Hora Sastra assigns it to evils, the difficulties of a life, and practice reads it alongside the birth chart for character and hardship themes. It is a descriptive layer; it does not predict misfortune, and nothing on this page interprets it.

Is trimshamsha the same as trimsamsa or the D30?

Yes. Trimsamsa and trimshamsha are spellings of the Sanskrit for a thirtieth part, and D30 is the shorthand. The name comes from the thirty degrees of a sign; the five bands are the classical way of distributing them.

Why does each band have a different width?

That is how the classical text sets them: five, five, eight, seven and five degrees in odd signs, reversed in even signs. Unlike the other divisions, the trimsamsa is not built from equal parts, which is why its boundaries need checking against the exact degree.