Guitar & piano playing

If I already play guitar, can I catch on to piano playing faster than if I didn’t?
Already knowing the guitar has it advantages when learning piano (although it depends on your training, experience, and abilities). If you learned to read music as part of your guitar studies, you’ll be able to apply that knowledge to learning the piano. For example, if you know the notes of a G chord are G, B, and D, or know that the notes of an A minor chord are A, C, and E, you simply have to find the corresponding keys on the piano to play the chord. Having knowledge of key and time signatures, and understanding the basic “road map” of music (it’s symbols and designations), puts you on a faster track when learning piano.
When it comes to the physical part of playing the piano, knowing how to form chords on guitar may not be of great help. The techniques are different as well as your relationship with the instrument (sitting in front of a piano rather than holding a guitar). Plus, on guitar, chords and melodies are formed with the left hand (if you are right-handed), whereas chords and melodies are played with both hands on piano. However, the strength and dexterity you developed in your hands playing guitar can make piano playing easier.
Many guitar techniques can be reproduced on piano. Playing an arpeggio (a series of notes of one of more chords) on piano is not unlike playing it on guitar. Instead of playing the piano keys to create the arpeggio, a guitarist holds a chord and plays its individual strings.
Once understood, chord inversions can be readily transferred from guitar to piano. An inversion is the same notes of a chord played in a different order (e.g., the notes C, E, and G being played as G, E, C). As a guitar player, you learned that chords can be played in many different ways. The same holds true for piano, though it can be argued that a piano is more versatile when it comes to forming chords.
Other aspects of playing such as tone and rhythm also transfer well. However, most would say creating a pure tone on guitar (for all strings played) is more difficult than on piano. A certain amount of strength is needed to press down the strings of a guitar, while the piano is more forgiving and requires sensitivity and touch more than strength. Having a good sense of rhythm is as important on piano as guitar. But as a piano player, rhythm and tempo comes from pressing the piano keys in a certain, consistent pattern. No longer will you be strumming to create the desired rhythm.
If you are used to playing sheet music (whether it be for guitar, piano, or both), you already have an idea how the two instruments work together. And you should be familiar with the guitar symbols that appear above a lot of music written for piano. Perhaps, without being aware of it, you’ve been forming a sense about how the piano is played.
Finally, you will be using different muscle groups and techniques when playing the piano. This can be a challenge at first but after a month or so, you’ll become comfortable with pressing keys instead of strings and you’ll begin to feel at home on the piano.