The degree of correlation between the source code of different software programs is important for uncovering plagiarism, trade secret theft, copyright infringement, and patent infringement. Other uses include locating open source code within a proprietary program and determining common authorship of different programs. Measurement of source code correlation is an important factor in any punitive determination of rights infringement. Existing measures of source code correlation tend to focus on only one or two types of correlation. This paper presents a theoretical basis for a measure of source code correlation predicated on various uses and requirements. The paper also describes a software tool that uses multiple algorithms to determine this correlation measure. At the conclusion the paper compares the results produced by this tool against results produced by other tools when examining a controlled set of correlated source code files and finds that the new tool is more accurate than other tools in determining all types of source code correlation.