Everyone in this field repeats that your sign shifts back by about one when you move from Western to Vedic astrology. Nobody says how often, or by how much, or which signs are worst affected. So we calculated it for every day of the year.
Of the 365 days in 2026:
The agreement is not scattered randomly. Each sign has a single window of five or six consecutive days, always at the end of the Western sign's range, where the two systems line up. Outside that window, the Vedic sign is the previous one.
| Western sign | Days | Usually becomes | Days | Days agreeing | Agreement window |
|---|---|---|---|---|---|
| Aries | 30 | Pisces | 24 | 6 | 14–19 Apr |
| Taurus | 31 | Aries | 25 | 6 | 15–20 May |
| Gemini | 31 | Taurus | 25 | 6 | 15–20 Jun |
| Cancer | 32 | Gemini | 26 | 6 | 17–22 Jul |
| Leo | 31 | Cancer | 25 | 6 | 17–22 Aug |
| Virgo | 31 | Leo | 25 | 6 | 17–22 Sep |
| Libra | 30 | Virgo | 25 | 5 | 18–22 Oct |
| Scorpio | 30 | Libra | 25 | 5 | 17–21 Nov |
| Sagittarius | 30 | Scorpio | 24 | 6 | 16–21 Dec |
| Capricorn | 29 | Sagittarius | 23 | 6 | 14–19 Jan |
| Aquarius | 30 | Capricorn | 24 | 6 | 13–18 Feb |
| Pisces | 30 | Aquarius | 24 | 6 | 15–20 Mar |
Libra and Scorpio are the least likely to keep their sign, agreeing on only five days each, 16.7 percent. Capricorn is the most likely at 20.7 percent, and even that is barely one birthday in five.
Stated in full so the result can be checked rather than taken on faith.
Boundary days are the only source of ambiguity: a person born within a few hours of a sign change may fall either side of it, and only a full birth-time calculation settles that. This affects roughly one day per boundary, so the 80.8 percent figure carries an uncertainty of about a percentage point.
The ayanamsa matters. A different ayanamsa moves every boundary by a fraction of a degree and would change the totals slightly. Ours is stated on the methodology page.
Western astrology measures the zodiac from the spring equinox, so it is tied to the seasons. Vedic astrology measures from the fixed stars. Those two starting points coincided roughly two thousand years ago, and the slow wobble of the Earth's axis — precession — has since opened a gap of about 24 degrees.
A sign is 30 degrees wide. A 24-degree gap therefore leaves only about 6 degrees of overlap, which is the five-or-six-day window in the table. The full explanation is on Vedic vs Western astrology.
The data is free to reuse with attribution (CC BY 4.0). Suggested citation:
The True Sign (2026). "Only 19% of birthdays keep the same sign in Vedic astrology." https://thetruesign.com/sign-shift/
Want to know which side of the line your own birthday falls on?
Check my chart80.8 percent. Of the 365 days in 2026, 295 produce a sidereal Sun sign different from the tropical one used in Western astrology. Only 70 days, 19.2 percent, give the same sign in both.
The two systems measure the zodiac from different starting points. Western astrology counts from the spring equinox; Vedic astrology counts from the fixed stars. Precession has opened a gap of about 24 degrees between them, which is most of a 30-degree sign.
Libra and Scorpio. Each keeps its sign on only 5 days of the year, 16.7 percent, against 6 days for most others.
The same 24-degree shift applies to every body in the chart, including the Moon. This study measures the Sun because that is the sign most people mean when they name theirs.
This page reports an astronomical calculation, and that part is checkable. It does not argue that either system is more accurate — they measure from different reference points and both report the sky correctly from their own. Astrology itself is offered here for reflection, not as prediction or advice.