How big is 78mm in inches? Leave a Comment / General Finest Reply 78mm in inches is 3.07086614 Read More: What tims is 9pm PST in Central time? How many linear ft in 1 acre? Related posts: What does I resist those in power mean? What are lines that intersect to form right angles? How tall is a 10 story building? Which member of Boyz II Men died? How many nickels are in a roll of nickels? READ: How many pints in a 5 gallon bucket?