There is not a single Rolls Royce and every model has a different length. So unless you specify which model you need the length of this question cannot be answered.
The 2014 Rolls-Royce Phantom is 19 ft. 2 in. (230 in.) long.
The 2011 Rolls-Royce Phantom is 19 ft. 1.9 in. (229.9 in.) long.
The 2013 Rolls-Royce Phantom is 19 ft. 2 in. (230 in.) long.
The 2008 Rolls-Royce Phantom is 19 ft. 1.7 in. (229.7 in.) long.
The 2012 Rolls-Royce Phantom is 19 ft. 1.9 in. (229.9 in.) long.
The 2012 Rolls-Royce Ghost is 17 ft. 8.6 in. (212.6 in.) long.
The 2004 Rolls-Royce Phantom is 19 ft. 1.7 in. (229.7 in.) long.
The 2010 Rolls-Royce Ghost is 17 ft. 8.6 in. (212.6 in.) long.
The 2006 Rolls-Royce Phantom is 19 ft. 1.7 in. (229.7 in.) long.
The 2009 Rolls-Royce Phantom is 19 ft. 1.7 in. (229.7 in.) long.
The 2011 Rolls-Royce Ghost is 17 ft. 8.6 in. (212.6 in.) long.
The 2005 Rolls-Royce Phantom is 19 ft. 1.7 in. (229.7 in.) long.