What is a Saptamsa (D7) chart and what is it read for?
A Saptamsa (सप्तांश, a seventh part) is one of the sixteen divisional charts set out in the Brihat Parashara Hora Shastra. Each sign is cut into seven equal parts of 4°17'8.57", each part is assigned to a sign, and collecting the assignments for the grahas and the ascendant gives a second chart drawn like the first. The classical assignment reads the D7 for progeny, children and the line that follows, which in Parashari reading is the territory of the fifth house. Astrologers read that house in the birth chart first and then open the D7 for the same question in more detail. Like every varga, it magnifies one department of the birth chart and is not read as a chart in its own right.
Seven parts of 4°17' each, not round numbers
Thirty degrees does not divide into seven neatly, so each saptamsa runs 4°17'8.57", an awkward figure that has to be carried precisely rather than rounded. Rounding to 4°17' accumulates nearly a minute of arc by the seventh part, which is enough to put a graha near the end of a sign into the wrong saptamsa. The engine divides exactly; the description here rounds only for reading.
The D7 lagna is where the chart is anchored
As in every varga, the ascendant's own longitude is divided by the same rule to give the D7 ascendant, and all twelve houses of the D7 are counted from that sign. A graha's house in the D7 therefore has nothing to do with its house in the birth chart, and the table prints both signs side by side so the difference is visible rather than assumed.
How is the D7 calculated, and what is the exact rule?
Take the sidereal longitude on the Lahiri (Chitrapaksha) ayanamsha and find the degrees within the sign. Divide by 30/7 to get which of the seven parts the graha falls in, numbered from zero. Then count that many signs forward from a starting sign: for an odd sign the count starts from the sign itself; for an even sign it starts from the 7th sign from it. So the first saptamsa of Aries is Aries, and the first saptamsa of Taurus is Scorpio, the 7th from Taurus. Because seven parts do not close the zodiac neatly, a sign's seven saptamsas run into the following signs rather than staying inside a tidy block. That is expected, and is a property of the rule rather than a fault in it.
Odd and even are positions, not elements
Aries is the first sign and so odd, Taurus the second and so even, alternating round the zodiac. The split is positional. Other divisions key off quite different properties (the D16 off modality, the D24 off a fixed starting sign), so an implementation that applies one rule to all sixteen vargas is wrong for most of them. This is the single commonest source of divisional charts that disagree between two pieces of software.
Why the 7th sign for even signs
Parashara states the rule rather than arguing for it, and commentators tie the seventh to the axis of partnership from which progeny is read. Whatever the reasoning, the text gives the rule and this engine follows it. The practical effect is that the D7 sign of a graha in an even sign is rarely the one a reader would guess from the birth chart, which is why the table prints both.
What does the 5th house of the D7 show?
It is the house the D7 is opened for, the fifth being the house of progeny in Parashari reading. The result names the sign of your D7 fifth house, its lord, and where that lord stands within the D7, plus any grahas occupying it. An empty house is ordinary and is read through its lord. Classical practice reads this beside the fifth house of the birth chart, the fifth lord, and Jupiter, which is the sthira karaka the texts assign to children. That is why Jupiter's D7 sign and house are reported separately in the result. All of it is what the tradition consults; none of it is a statement about a reader, and this page does not make one.
Can a D7 chart say anything about having children?
It cannot, and no page on this site will pretend otherwise. Whether someone has children is a medical and personal matter, and nothing in a divisional chart has been shown to bear on it. The claim is not in the classical texts in the form modern sites present it, and it would not be responsible even if it were. What the tradition does is read the fifth house and the D7 for themes around progeny and the line that follows, in its own vocabulary, and that is what this page reports. If you have a question about your health or your family, the person to ask is a doctor. A chart is a lens the tradition uses; it is not a diagnosis and it is not a forecast.
What the classical fifth house actually covers
Parashara reads the fifth for purva punya (merit carried forward) along with intelligence, counsel, mantra, creative issue and progeny. Children are one item on a list that is mostly about the mind and what it produces, and the Jaimini Putra karaka carries the same double sense of children and creative output. Narrowing the house to one topic is a modern simplification, not the classical reading.
Why we report Jupiter's position and stop there
Jupiter is the sthira karaka of progeny, so writers who read the D7 look at it beside the fifth house and the fifth lord; leaving it out would misrepresent the technique. Printing where it stands is reporting the tradition; drawing a conclusion from it about a reader would be inventing one. The result gives the sign and the house, and the reading stays with whoever is qualified to make it.
How much does the birth time change a D7 chart?
A seventh division magnifies birth-time error sevenfold. The ascendant moves 30° in roughly two hours, so it crosses a 4°17' saptamsa in about seventeen minutes. A time rounded to the nearest quarter hour can therefore land the D7 lagna in the neighbouring sign, and every house of the D7 is counted from there. The Moon crosses a saptamsa in about eight hours, so it is much safer, and the slow grahas will not move at all on any realistic error. The honest summary is that with an uncertain time the graha placements in the D7 are largely reliable and the ascendant is not, and unfortunately that is the half the house numbers depend on.
How does the D7 relate to the D9, the D10 and the whole Shodasavarga?
They are siblings with different divisors and different assignments. The D9 navamsa divides by nine and is read for marriage and the second half of life; the D10 dasamsa divides by ten for work and standing; the D7 divides by seven for progeny. Sixteen such charts make the Shodasavarga, from the D1 rashi to the D60 shashtiamsa, and the full kundli on this site draws every one of them with its lagna. The division rules differ genuinely between charts, so they cannot share one arithmetic shortcut. Houses in every varga here are whole-sign, counted from that varga's own ascendant; cusp-based systems such as Bhava Chalit or Placidus are not applied to divisional charts in classical practice.
Shodasavarga means sixteen charts, not one
Parashara's sixteen run D1, D2, D3, D4, D7, D9, D10, D12, D16, D20, D24, D27, D30, D40, D45 and D60, each with its own division rule and its own department. Some schools weight a subset (the Shadvarga six, the Saptavarga seven), and the choice of subset is itself a tradition rather than a fact. Our full kundli draws all sixteen so the reader can see the set rather than a selection.
Vargottama across the vargas
A graha holding the same sign in a divisional chart as in the birth chart is called vargottama, and classical writers read the repetition as emphasis. The table on this page flags it for the D7. It is more common in some divisions than others because of how the starting signs fall, so it is worth noticing rather than treating as rare.
How this is calculated
Nirayana rashis with the Lahiri (Chitrapaksha) ayanamsha and whole-sign bhavas, computed to arc-second accuracy. Sunrise and sunset are the ones almanacs show, the Sun's upper edge with refraction, so the daily windows agree with the calendars you compare them with. More on our method.