Calculation research & comparison
How Often Do Mercury and Venus Share Your Sun Sign? 100 Years
By Cheng Xu ·
Because Mercury and Venus orbit inside Earth’s orbit, they never stray far from the Sun in our sky. Across 36,525 daily 12:00 UTC samples from 1951 through 2050, Mercury shares the Sun’s tropical sign on 51.28% of days and is one sign before or after on the remaining 48.72%. Venus shares the Sun’s sign on 23.55% of days, sits one sign away on 58.49%, and two signs away on 17.96%.
Check your own placements in the Mercury sign calculator and Venus sign calculator.
Sign distance from the Sun, 1951–2050 (36,525 daily samples)
We sampled apparent geocentric tropical longitudes at 12:00 UTC on every calendar day from January 1, 1951 through December 31, 2050, and measured the wrapped sign index difference signIndex(planet) − signIndex(Sun).
| Relative sign position | Days in 1951–2050 | Share of sample |
|---|---|---|
| One sign before the Sun (−1) | 8,888 | 24.33% |
| Same sign as the Sun (0) | 18,730 | 51.28% |
| One sign after the Sun (+1) | 8,907 | 24.39% |
| Relative sign position | Days in 1951–2050 | Share of sample |
|---|---|---|
| Two signs before the Sun (−2) | 3,276 | 8.97% |
| One sign before the Sun (−1) | 10,622 | 29.08% |
| Same sign as the Sun (0) | 8,601 | 23.55% |
| One sign after the Sun (+1) | 10,743 | 29.41% |
| Two signs after the Sun (+2) | 3,283 | 8.99% |
Why Mercury cannot be two signs away—and Venus cannot be three
Each zodiac sign spans 30° of ecliptic longitude. In our 100-year daily sample, Mercury’s largest absolute ecliptic longitude difference from the Sun is 27.79° (recorded on 1967-03-31 12:00 UTC). The sampled differences stay below 30°, so no sample places Mercury two signs away from the Sun. For sampled Aries Suns, Mercury is in Pisces, Aries or Taurus.
Venus orbits farther from the Sun and reaches a maximum sampled absolute ecliptic longitude difference of 47.22° (on 2049-01-03 12:00 UTC). Because 47.22° is greater than 30° but less than 60°, Venus can reach a second adjacent sign (for example, an Aries Sun at 25° Aries with Venus at 5° Gemini, 40° ahead), while no sample places Venus three signs away from the Sun.
Why a calculator showing “Sun opposite Venus” is a bug
If an astrology app or AI chatbot generates a natal chart where Mercury is square the Sun or Venus is opposite the Sun, the positions were not computed from real orbital mechanics. Inner planets can form only conjunctions (or, for Venus, a narrow semi-square or sextile within 48°) with the natal Sun. In synastry or transit charts, however, one person’s Venus can form any aspect to another person’s Sun.
Method and limits
Longitudes are evaluated at 12:00 UTC daily over 100 calendar years using Astronomy Engine. Daily noon sampling measures ephemeris time shares rather than weighting by seasonal human birth rates, and continuous extrema between noon samples can exceed the sampled maxima. These longitude differences omit ecliptic latitude and are not the full angular separation on the sky.
Download the research and comparison JSON · Reproduce these tables (TypeScript source). Output is licensed under CC BY 4.0; credit Natal Chart Lab and link to this article.
Cite this research
Natal Chart Lab (2026). How Often Do Mercury and Venus Share Your Sun Sign? 100 Years. https://natalchartlab.com/articles/mercury-venus-sign-same-as-sun-probability; supporting data. Reuse under CC BY 4.0: credit Natal Chart Lab, link to this article and the license, and indicate changes.
Prepared with AI assistance and checked against calculation code and saved data. Astronomical calculations and dataset statistics do not establish astrological claims about personality, relationships or future events.