Two birth charts read against each other - every reading traced to the chart quantity and the text behind it
This page compares two complete birth charts and, for each finding it reports, shows four separate things: the reading, the rule that produced it stated in plain words, the exact chart quantities the rule read with each labelled by which chart it came from, and the source that authorises it at chapter and verse. Opening the trace under any finding shows the working. Nothing on this page asks to be taken on trust.
The sections are ordered by how well attested they are, not by how flattering they are. The two Jataka Parijata verses come first because they are the only rules in the Sanskrit jataka corpus that test one nativity against another at a numbered verse. The techniques with no classical locus at all - the bhava overlay, graha drishti cast across two charts - come last among the readings, and they say so on their own citation chips rather than borrowing authority from the ones above them.
Vaidyanatha Dikshita's chapter on the seventh, eighth and ninth bhavas contains two rules that name the other person's chart explicitly. The first collects the grahas occupying or aspecting the seventh bhava from one person's Moon and asks whether the partner was born in a sign those grahas own.
The second adds the longitudes of the lagna lord and the seventh lord and reads the rasi and amsa of the sum as the partner's. Both verses state themselves symmetrically, so both are run in both directions and the two directions are reported separately.
Two limitations are printed on the findings rather than left out. The sloka number for the first rule is not settled: the only digitisation available prints 35 over two consecutive passages and numbers the next one 36, so the rule sits at 33, 34 or 35 and is cited as a range. And Phaladeepika X.11 answers the same question by a different construction entirely, so neither method is presented as the classical one.
The Manglik list in general use flags Mars in the first, second, fourth, seventh, eighth and twelfth houses. Brihat Parashara Hora Shastra 80.47 names four: the twelfth, fourth, seventh and eighth, and only when Mars is neither joined to nor aspected by a benefic. The benefic escape is part of the rule rather than a concession applied afterwards, which matters, because a yoga that never formed cannot be cancelled.
Verses 48 and 49 then supply the thing folk practice repeats without a source: the same configuration applies to a man's chart, and when two people who both carry it marry each other the yoga ceases to have effect. That is one of only two places in the whole of Parasara where two nativities are genuinely weighed against each other.
This page runs the four-house form beside the six-house form the rest of the app uses, and names the divergence rather than reconciling it. The chapter's own result language belongs to stri-jataka and is not rendered.
An aspect is a difference of two longitudes, and the ayanamsha is a constant subtracted from both, so every separation and every orb on this page is identical whether the chart is drawn tropically or on Lahiri. The sign labels move; the geometry does not.
Tetrabiblos IV.5 instructs that the luminaries of two nativities be read together in trine or sextile, which is the oldest located two-chart marriage rule in any tradition, and those contacts carry that citation. The rest of the grid is a modern extension of it and carries an unsourced label.
The orb table in force is printed on the page, because every published table differs and a reader cannot check a result against their own software otherwise. Applying and separating are deliberately not computed: neither chart is moving, so nothing is approaching or leaving anything, and software that prints those values for a two-chart comparison is reading natal speeds as if one chart were a transit.
An earlier version of this page labelled whole-sign distances with Western aspect names - conjunction, opposition, trine, square - which is a category error in both directions.
Two grahas at 29 degrees of Mesha and 1 degree of Mithuna are 32 degrees apart and form no sextile; two at 1 and 29 degrees of Mesha share a sign and are 28 degrees apart, which is no conjunction under any published orb. It also compared each graha only with its own twin, so Venus against the partner's Mars could not appear at all.
Both honest repairs are now shipped, in sections that never share a heading. The Jyotisha section reads Parasara's own drishti table across the two charts - full for the seventh from any graha, and the special aspects for Mars, Jupiter and Saturn - and states that casting drishti between two nativities is modern practice even though the table is classical. Drishti is a sign relationship with no orb, so the degree figure beside each row is labelled a separation rather than a tolerance.
No text compares two natives' running dashas. Both charts' Vimshottari periods are shown side by side and where they overlap in the calendar, and that overlap is reported as an interval intersection rather than as a finding. The seventh lord's own period is a live disagreement between two classical texts and both render: Phaladeepika X.13 gives marriage in the dasha of the planet owning, occupying or aspecting the seventh house, while BPHS 48.5-8 reads the same period as a maraka one.
The genuine two-party timing layer is in muhurta. Tara-bala and Chandra-bala must be satisfied for both parties, and Kalaprakasika chapter XIV permits transiting Jupiter only in the second, fifth, seventh, ninth and eleventh from the janma rasi. The test is an intersection: one partner's Vipat, Pratyari or Naidhana tara disqualifies a day however good the other's is. It is a floor rather than an election, and the muhurta finder does the rest.
Cross-chart Darakaraka matching - your Darakaraka is their ascendant, your Atmakaraka is their Darakaraka - saturates the internet and traces to no author, no book and no verse. A complete reading of the Jaimini Upadesa Sutras and of BPHS chapters 30 and 32 finds no cross-chart karaka rule anywhere.
This page computes the configuration in your own two charts, shows it to you, and says that nothing authorises reading it, because a page that quietly omits a test looks identical to a page that never heard of it.
Parasara's guna-class comparison at BPHS 77.11-13 is refused for a different and stronger reason: verse 9 directs the astrologer to classify the person by their observed conduct rather than from the horoscope, so the rule is not a horoscopic rule and no chart arithmetic can stand in for it. Both refusals are rendered as findings, against your own charts, with the reason attached.
No compatibility percentage, no total and no band. The page counts how many findings fell on each side and says plainly that the count is a statement about the findings rather than about two people. Adding them would need weights, and no classical text weights a chart comparison at all.
That is true of the famous one too. Muhurta Chintamani gives the eight-koota ladder and stops; the eighteen-out-of-thirty-six pass mark appears first in a modern Hindi commentary rather than in any verse, and B. V. Raman notes that the author of Prasna Marga allots no units to the kootas.
The classical thresholds are counts rather than scores - Kalaprakasika chapter XIII wants at least five of ten poruthams satisfied, Prasna Marga at least five of its twenty-three. The 36-point Ashtakoot lives on the Kundli Matching page, where its own provenance is stated.
A comparison only means something if the two charts are computed the same way, so both use the same zodiac, the same ayanamsha and the same house system: sidereal, Lahiri by default, and Whole Sign. The comparison endpoint refuses a request whose two charts name different ayanamshas outright, because a comparison across two zodiacs is not a comparison. The settings in force are printed above the findings.
Recent comparisons are kept in your own browser so a pair can be reloaded without retyping either set of birth details, and any entry can be deleted. Nothing beyond the birth data is required or stored: no relationship type, no gender field, and no account. Where a cited verse writes its rule against the bride specifically, this page applies it to both charts, shows each side's result separately, and labels that symmetrising as its own choice rather than the text's.