how to calculate time for timer relay
Capacitor resistor charge time: -



If the applied voltage is 12V the capacitor charges to 63.2% of 12V in a time equal to capacitance in farads x resistance in ohms. In twice this time it gets another 63.2% closer to 12V i.e. 86.5%. Each duration of time equal to CR it gets another 63.2% closer. See below: -




  how I can calculate the time for C1 to be fully charged?


Theoretically a capacitor never gets to 12V but, for practical purposes it gets to over 99% charge after 5 x CR.

As for the circuit in the question, it appears to be using a 555 timer chip and the relevant point at which this activates the chip is not to be confused with "fully charged". Read the data on the 555 to determine what that point in time is.