The answer is 58.646 day.
It takes 1407.6 Earth hours for Mercury to make one full spin (or rotation) around its axis.
Mercury does not spin as fast as Earth, so a Mercurian day (the time it takes a planet to rotate once) is 59 Earth days.
the answer is 88 days ,making 88 earth days 1 mercury year
It takes Mercury much longer than planet Earth to make a complete spin on its axis. Mercury rotates once every 1407 hours or 58 days.
A Mercurian "day" the (time it takes it go spin once on it's axis) is equal to 58.65 earth days. Mercury turns on it's axis very, very slowly.
Because of the periods of Mercury's orbit and spin, a year (complete orbit around the sun) on Mercury is about 88 Earth days long, while a day (time for the Sun to appear in the same place in the sky) is twice that length, at about 176 Earth days long.
Mercury takes 88 Earth days to go around the Sun, but strangely, its day is twice as long taking 176 Earth days to rotate just once! Mercury's slow spin is evidence of why the planet has a magnetic field just 1% as strong as Earth's. (This may have been a very long answer)
Venus: Venus has a "sidereal" day (rotation period)that's longer than its "year" (orbital period).A siderealday on Venus is equal to about243 Earth days, whereas a year is about 224.7 Earth days.Mercury:It takes Mercury about58.64 Earth days to spin on its axis - which is one Mercury siderealday. However, the "solar " day on Mercury is about 176 Earth days long.It takes Mercury about87.96 Earth days to orbit the Sun, which is defined as one Mercury year.So, for Mercury it is thesolar day, not the sidereal day that is longer than its year.(A solar day on Earth is 24 hours. A sidereal day, which is how long it takes Earth to spin on its axis, is about 4 minutes shorter.A year on Earth is about365.25 days - which is how long it takes Earth to orbit the Sun.)
88 days
The gravity of the Sun has slowed the rotation of Mercury, so it takes almost 59 Earth days to spin once on its axis (58.646 days).At the same time, the relatively brief orbital period (Mercury year) is only 88 days long, even further reducing the apparent motion of the Sun as seen from the planet. A "solar day" (sunrise to sunrise) on Mercury lasts 176 Earth days, or twice as long as its year!
Venus or Mercury, depending on the definition of "day" used. It takes Venus 243 Earth days to spin on its axis relative to the background stars (a "sidereal day"). It takes Venus 224.7 Earth days to orbit the Sun (its year). However, a "solar day" is only 116.75 Earth days long due to the combination of rotation time, orbit time and spin direction. (Venus spins in the other direction to Earth and most other planets.)Mercury has a "sidereal day" of about 58.6 Earth days and a year of about 88 Earth days.
Mercury, just as Earth rotates alone its axis. The spin is from left to right along this axis with one rotation lasting nearly 176-days on Earth. Needless to say it is a very slow spin in comparison.