Embodiments of the present invention provide a method, system, and computer program product for qualifying changes to an instruction set in source code. In an embodiment of the invention, a method for quantifying changes to an instruction set in source code can be provided. The method can include receiving text in a code editor as an edit to source code of a computer program querying a data store of code change costs with at least a portion of the edit. The method additionally can include retrieving in response to the query a code change cost associated with the edit. Finally, the method can include displaying in the code editor the retrieved code change cost.