Check whether Budhaditya Yoga is present in your Vedic birth chart - the Sun and Mercury in one sign - and get a sourced, honest read. The tool gives a binary verdict, quotes both classical statements in full instead of merging them, reports Mercury’s combustion as a measurement rather than a grade, and compares your result with a computed base rate. Uses sidereal Lahiri ayanamsa, the same engine as our Kundli generator.
100% private - the Budhaditya calculation runs entirely in your browser. No birth data sent anywhere.
The Sun and Mercury move slowly, so this result is usually the same all day. We still scan the whole birth date and report every distinct result rather than assuming noon. If it changes, we show exactly when.
Supports 1900 onwards for better calculation reliability.
Budhaditya is read from the Sun and Mercury sharing a sign. Both move slowly, so the birth date and place are usually enough; an exact time only matters if one of them changes sign that day.
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astrology| Core condition | The Sun and Mercury in the same sign (whole-sign “one house”) |
| Input | Date and place of birth; time optional (both bodies move slowly) |
| Verdict | Binary: present or absent. No weakened tier, because no located verse defines one |
| Base rate | About 51.2% of 40,000 sampled instants, versus 8.33% naive - common, not rare |
| Combustion | Reported with its margin as an observation; about 62% of formed cases. Never graded |
| Not modelled | Mutual aspect, parivartana, Mercury’s dignity, any ascendant restriction |
| Engine | MIT-licensed Meeus / VSOP87 (astronomia); Lahiri ayanamsa; same as Kundli |
| Remedies | None - this is a classification tool, not advisory |
| Privacy / cost | 100% client-side; no data leaves the browser; free |
Budhaditya Yoga (budha = Mercury, aditya = the Sun) is the combination of the Sun and Mercury in one house of a Vedic birth chart. The tradition links it to intelligence, learning and reputation, which is why it is one of the most frequently quoted yogas in popular astrology writing.
It is worth stating plainly what it is not. It is not rare, it is not a guarantee of intellect or success, and the name itself is not classical. This tool treats it as a documented combination to classify honestly, not a headline to sell.
The tool finds your Sun sign and your Mercury sign and checks whether they are the same, using whole signs. That is the condition both located verses actually state: Phaladeepika Ch.18 heads a chapter on conjunctions of two planets, and Saravali Ch.15 v.4 opens with the Sun and Mercury being in one house. Because both positions are geocentric and do not depend on where you were born, this check needs only your birth date and place, not an exact time. If your birth time is unknown, the tool scans the whole day and reports whether the verdict is stable or exactly when it changes, rather than silently assuming noon.
What the tool deliberately does not do is widen the rule. A conjunction measured by orb, a mutual aspect, or a parivartana (sign exchange) would each be a different test, and neither verse supports them here. Mercury’s dignity and any ascendant-based restriction are likewise left out. Every one of those would need its own source, and adding them silently is how a calculator drifts away from the texts it claims to implement.
Two independent classical texts state a result for this combination, and the tool shows both in full rather than blending them into one sentence:
These are differently emphasised, not contradictory. Saravali opens on service and unsteady wealth, which reads as a caution, but the same verse continues into fame, money, nobility and learning, which substantially overlaps Phaladeepika’s reading. Quoting only the opening clause would manufacture a conflict between the two texts that the full verse does not support, so the tool stores and displays the complete statement.
On the name: neither verse uses it. R. Santhanam’s note to Saravali Ch.15 v.4 records that this conjunction goes by the name Buddhaditya yoga, so the combination is classical while the label comes from a modern translator’s commentary. That same note also reports two further positions the tool discloses but does not apply, from Jataka Martanda (an ascendant restriction) and Jatakabharana (a different result statement). Both reach us through the commentary reporting those works, not from the works themselves.
Most pages that describe this yoga imply it marks you out. The astronomy says otherwise. Mercury never exceeds roughly 28 degrees of elongation from the Sun, and a sign is 30 degrees wide, so the two are in the same sign a large fraction of the time. A naive model that treated them as independent would predict 8.33% (1 in 12). Our sweep over 40,000 sampled birth instants (1900 to 2099) finds it formed in about 51.2% of them - roughly 6.1 times the naive figure. Of the formed cases, about 62% have Mercury combust, which is itself a consequence of the same closeness.
One honest caveat about the method: the Sun-Mercury relationship is geocentric and location-independent, so we sample instants over time and do not use a birthplace grid - geography does not change this base rate. And the figure is a share of sampled instants, not a measured share of the human population, whose birth dates are not uniformly distributed. The takeaway stands either way: about half of sampled instants carry this combination, so its presence is ordinary and cannot by itself explain anything about a person.
Budhaditya Yoga is the combination of the Sun (Aditya) and Mercury (Budha) in one house of a Vedic birth chart. Two classical texts describe it: Phaladeepika (Mantreswara) Ch.18 sloka 1 says the person will be clever, intelligent, famous and happy, and Saravali (Kalyana Varma) Ch.15 v.4 gives a longer statement covering service, unsteady wealth, sweet speech, fame and money, nobility, and strength, beauty and learning. This tool checks the condition both verses actually state - the Sun and Mercury sharing a sign - and shows both statements in full rather than merging them.
No, and this is the single most important thing to know about it. Mercury never strays more than roughly 28 degrees from the Sun, while a sign is 30 degrees wide, so the two share a sign far more often than chance would suggest. Our sweep over 40,000 sampled birth instants (1900 to 2099) finds the combination formed in about 51.2% of them, against the 8.33% a naive 1-in-12 independent model would predict. That figure is a share of sampled instants over time, not a measured share of any population, because real birth dates are not uniformly distributed. A combination that forms in roughly half of sampled instants is not a distinction.
No, and it is worth being precise about this. Neither Mantreswara's verse nor Kalyana Varma's verse uses the name. The label reaches us through R. Santhanam's note to Saravali Ch.15 v.4, which records that this conjunction goes by the name Buddhaditya yoga. So the combination is classical and the name is supplied by a modern translator's commentary. Note also that Santhanam spells it Buddhaditya with a double d, while the common form today is Budhaditya; both refer to the same Sun and Mercury combination.
Not according to the two verses this tool is built on, and so this tool does not treat it as a cancellation or a weakening. Mercury being combust means it sits within its combustion orb of the Sun, which is common precisely because Mercury stays close to the Sun. Neither Phaladeepika Ch.18 sloka 1 nor Saravali Ch.15 v.4 makes Mercury's condition part of the rule, so grading the yoga on combustion would be adding a rule the sources do not contain. The tool reports combustion as a measurement, with how far inside or outside the orb Mercury sits, and leaves the verdict binary: present or absent.
No. This version detects the same-sign conjunction only. Both located verses describe the Sun and Mercury being in one house, which is a sign-based statement, so a conjunction by orb, a mutual aspect, or a parivartana (sign exchange) would each be a different rule needing its own source. Rather than quietly widening the definition, the tool implements what the verses say and states this limit openly.
Yes, and the tool discloses two it does not apply. Santhanam's note to Saravali Ch.15 v.4 reports that Jataka Martanda restricts this yoga to Leo, Aries and Virgo ascendants, and that Jatakabharana gives a different result statement (an eloquent speaker, a king's minister, earning through service, skilful in arts and Vedas). Both reach us through the translator's commentary reporting those works, not from those works directly, so they are shown as disclosed variants rather than folded into the verdict. This version applies no ascendant restriction.
Enter your date and place of birth above and the tool finds your sidereal Sun sign and Mercury sign and reports whether they match. Birth time is optional here: both bodies move slowly, so the answer is usually the same for the whole day, and if it is not, the tool scans the day and shows exactly when it changes rather than assuming noon. If you want to read it off a chart you already have, look at which sign the Sun occupies and which sign Mercury occupies. If it is the same sign, the yoga is present by the definition both located verses state. Nothing else is needed, and no house or ascendant information enters this check.
This tool uses the same SIGN, and in whole-sign Vedic practice that is the same thing as the same house, because each sign is one house. The distinction matters if you use a different house system such as Bhava Chalit or Placidus, where a planet can sit in one sign but be counted in a neighbouring house. Both located verses phrase the condition as the two being in one house, which in the whole-sign frame those texts assume means one sign, so a sign-based test is the faithful reading. This tool does not compute Bhava Chalit, and says so rather than implying its result is house-system independent.
Both located verses describe it positively, but the honest answer is that it is too common to carry much weight on its own. Phaladeepika associates it with cleverness, intelligence, fame and happiness, and Saravali with sweet speech, fame, money, nobility and learning, alongside service and unsteady wealth. Set against that, the combination is formed in roughly half of sampled instants, so it cannot be what distinguishes one chart from another. Treat it as an ordinary, well-documented placement rather than a verdict on a person, and note this tool classifies the combination only. It does not predict outcomes and prescribes no remedies.
They involve different planets and different geometry, and our two calculators treat them differently for a sourced reason. Budhaditya is the Sun and Mercury in one sign, a conjunction, and its verdict here is binary because no located verse grades it on Mercury's condition. Gaja Kesari is Jupiter in a kendra (the 1st, 4th, 7th or 10th) from the Moon, an angular relationship rather than a conjunction, and our Gaja Kesari calculator carries a three-state verdict because the Brihat Parashara Hora Shastra supplies a cited stricter definition that Budhaditya has no equivalent of. Both are common rather than rare, and both pages publish a computed base rate instead of implying a rare distinction.
For your full Vedic birth chart - all nine grahas, the D1 and D9 charts, Vimshottari Dasha, and Mangal Dosha - see the Free Kundli Generator. For other classical combinations read the same way, the Raj Yoga Calculator detects the kendra-trikona family with the same base-rate approach, and the Gaja Kesari Yoga Calculator applies it to Jupiter and the Moon.
scripts/budhaditya-base-rate.ts and its committed output) for the incidence over 40,000 sampled instants, including the stability re-run and the raw counts behind every percentage on this page.