Every astrology site says its calculations are accurate. Very few say what they checked them against, for how long, and what the differences were. This post is that check, for Steer's panchang engine: every day for 1,124 consecutive days, compared against the Government of India's official almanac, with the results quantified.

The reference: India's official almanac

The natural standard for a panchang is the one the Government of India itself publishes. The Rashtriya Panchang, prepared by the Positional Astronomy Centre in Kolkata, has been the country's official almanac since the Calendar Reform Committee's work in the 1950s. It lists each day's tithi, nakshatra, yoga, and karana with their ending times, the daily planetary positions, the ayanamsa, and the festival dates, all computed on the sidereal zodiac with the Lahiri (Chitrapaksha) ayanamsa the committee standardized.

That makes it the right benchmark for a simple reason: it is independent, it is published to a fixed methodology, and it is the standard against which Indian civil and religious timekeeping is set.

What we compared

The benchmark harness computed, with Steer's engine, the full panchang for every one of 1,124 consecutive days and compared each value against the corresponding published Rashtriya Panchang entry:

  • Element names: the tithi, nakshatra, yoga, and karana current at sunrise each day, plus the lunar month.
  • Ending times: the clock time at which each element ends, as printed in the almanac.
  • Planetary longitudes: the daily sidereal positions of the Sun, Moon, and planets.
  • The ayanamsa: the daily Lahiri value itself.

The engine was given only what the almanac's own tables assume: the date and the almanac's reference conventions, including its central reference location and the Lahiri ayanamsa. No per-day adjustment, no correction pass, no special-casing of difficult days.

The results

Element names: 1,124 of 1,124 days in agreement. The tithi, nakshatra, yoga, and karana named for each day matched the official almanac on every single day of the benchmark, including the awkward ones: days when a tithi is skipped or repeated, days when an element ends within minutes of sunrise, and month boundaries with adhika (intercalary) months.

Ending times: within one minute. The Rashtriya Panchang prints ending times to the minute, and the engine's computed times agreed within that printed resolution across the benchmark period.

Planetary positions and ayanamsa: within a fraction of an arcsecond. The underlying sidereal longitudes, computed from the Swiss Ephemeris on NASA JPL planetary data, agreed with the almanac's positions at the sub-arcsecond level, which is far below anything that could change a tithi, a nakshatra, or a chart placement.

Why sub-minute agreement is the honest ceiling

A tithi ends at the exact moment the Moon completes another 12 degrees of separation from the Sun. Computing that moment more precisely than the almanac prints it is possible; verifying beyond the almanac's printed minute is not. So the benchmark reports agreement at the reference's own resolution rather than claiming digits the comparison cannot support. Where the printed value and the computed value rounded to different adjacent minutes, the difference was always within the rounding boundary.

The same honesty applies to the one class of genuine differences we found across sources generally: conventions. Sunrise definitions, reference locations, and month-naming systems legitimately differ between traditions, and two correct almanacs can print different values because they answer slightly different questions. Steer resolves this by following the Rashtriya Panchang's conventions throughout, so that "correct" always means "matches India's official standard."

What this means for the tools you use here

Every panchang value on this site — the daily panchang, the city pages, the values quoted inside articles — comes from the engine this benchmark tested. So do the birth charts, because a kundli is built from the same planetary positions the benchmark verified to sub-arcsecond agreement: the same Swiss Ephemeris foundation, the same sidereal zodiac, the same Lahiri ayanamsa.

Accuracy in astrology software is not a marketing adjective; it is a measurable property. We measured it, against the most authoritative reference available, for over three years of consecutive days. The result is an engine that agrees with India's official almanac on every named element, every day, with timings at the almanac's own printed resolution — and that is the calculation layer under everything Steer does, from the free tools on this site to Steer Astro in ChatGPT.