Every important act in life — laying a foundation, signing a deed, starting a new venture, performing a ritual — has a "right time" when the sky's mood is favourable to that act. Muhurta is the Vedic discipline of picking that moment. The RVA Muhurat Calculator is our attempt to make this 2000-year-old discipline practical for a smartphone screen.
This calculator does not invent new rules. It bundles the classical rules that practising astrologers actually use — the same checks a temple priest does on paper before he writes down a lagna-patrika — and runs them across a date range so you can see, at a glance, which slots survive every filter.
How the calculator is organised
The filters in the All Filters drawer are grouped into seven sections, in this order:
- Rahitam — Panchaka exclusions.
- Tarabalam — Star-strength compatibility against the native's birth star.
- Nakshatras — Which of the 27 lunar mansions are acceptable.
- Ascendants — Which of the 12 rising signs the event lagna may fall in.
- Placements — Where each of the 9 planets must sit at event time.
- Panchanga — The five limbs (Varam, Tithi, Yoga, Karana, Masam) plus three tithi-flavour refiners (Mrityu Tithi, Sunya Tithi, Chandra Balam).
- Kalam — Five time-window switches: Abhijit and Brahma muhurtas (prefer-only), and Rahu / Yamaganda / Gulika kalams (skip-inside).
Every slot the calculator returns has been checked against every active filter. A slot only appears in the result calendar if it survives all of them.
Rahitam
"Rahitam" literally means "free of" — Panchaka Rahitam are the windows that are free from the five inauspicious panchaka types. The Panchaka classification splits time into six buckets: Panchaka Rahitam (clean), Mrityu Panchaka (death), Agni Panchaka (fire), Raja Panchaka (royal), Chora Panchaka (theft) and Roga Panchaka (disease). For routine work most astrologers insist on Panchaka Rahitam only.
See: 01 — Panchaka Rahitam.
Tarabalam
Tarabalam ("star strength") measures how the day's nakshatra relates to the native's birth nakshatra in a 9-step cycle. The nine taras are: Janma, Sampat, Vipat, Kshema, Pratyak, Sadhaka, Vadha, Mitra, Parama Mitra. Vipat (3rd), Pratyak (5th) and Vadha (7th) are traditionally avoided; the others are favourable.
See: 02 — Tarabalam.
Nakshatras
The 27 lunar mansions each carry their own deity, lord, gana and quality (movable, fixed, mixed, etc.). For any given act, classical texts prescribe which nakshatras are appropriate — for example, fixed nakshatras for foundation laying, swift nakshatras for journeys.
See: 03 — Nakshatras.
Ascendants
The rising sign at the moment of the event matters as much as the moon's nakshatra. Fixed ascendants (Taurus, Leo, Scorpio, Aquarius) are favoured for long-term commitments; movable ascendants (Aries, Cancer, Libra, Capricorn) for travel and trade.
See: 04 — Ascendants.
Placements
For each of the 9 planets (Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Rahu, Ketu) you can constrain which of the 12 houses it must occupy at event time. By default all houses are allowed; tighten it to demand that, say, Jupiter is in the 1/4/5/7/9/10 (kendras / trikonas) and malefics are in 3/6/11 (upachayas).
See: 05 — Placements.
Panchanga
The five-limbed almanac: Varam (weekday), Tithi (lunar day), Yoga (sun-moon angle), Karana (half-tithi) and Masam (lunar month). Three more tithi-flavour switches sit in the same section: Mrityu Tithi, Sunya Tithi and Chandra Balam.
Sub-pages: Varam · Tithi · Yoga · Karana · Masam · Mrityu Tithi · Sunya Tithi · Chandra Balam.
Kalam
The day is split into eight unequal parts; specific parts are ruled by malefic planets and called kalams (literally, "times"). The Kalam section gathers five such windows. Two are prefer-only (Abhijit Muhurta, Brahma Muhurta) — turn them on and the calculator returns only those windows. Three are skip-inside (Rahu Kalam, Yamaganda, Gulika Kalam) — turn them on and the calculator excludes those windows.
Sub-pages: Abhijit Muhurta · Brahma Muhurta · Rahu Kalam · Yamaganda · Gulika Kalam.
How to read the results
The calendar view colours each day by the number of surviving slots — red for none, light-green for a handful, deeper green for many. Click any green cell and the slot list below shows the exact HH:MM windows that passed every filter, with the nakshatra, tithi, yoga, karana and ascendant for each slot. Export to CSV from the slot panel to share with a priest or family.
Start with the defaults (all-clean), then add filters one at a time. If the calendar goes red, ease off — every astrologer has a different threshold, and "no perfect day" usually means a few of your filters are pulling in opposite directions.
Where to go from here
Open the Muhurat Calculator itself, or browse the sidebar on the left to read about any individual filter. Every concept page tells you what the filter does, which classical rule it is based on, and the practical effect of switching it on.