makepagesmultipleof.tex

% LaTeX macro for making the page count of a LaTeX 
% document a multiple of some particular number

\def\addemptypage{
  \pagebreak
  \thispagestyle{empty}
  \phantom{abc}
}

\def\makepagesmultipleof#1{
  \newcount\a 
  \loop
    \a=\value{page}
    \divide\a by #1
    \multiply\a by #1
    \ifnum\value{page}=\a \else
    \addemptypage
  \repeat 
}

% In the bottom of your document-clause, do this:
\makepagesmultipleof4