Spreadsheets can be viewed as a highly flexible programming environment for end users. Spreadsheets are widely adopted for decision making and may have a serious economical impact for the business. However, spreadsheets are staggeringly prone to errors. Hence, approaches for aiding the process of pinpointing the faulty cells in a spreadsheet are of great value.

We present a constraint-based approach, ConBug, for debugging spreadsheets. The approach takes as input a (faulty) spreadsheet and a test case that reveals the fault and computes a set of diagnosis candidates for the debugging problem. Therefore, we convert the spreadsheet and a test case to a constraint satisfaction problem.

We perform an empirical evaluation with 78 spreadsheets from different sources, where we demonstrate that our approach is light-weight and efficient. From our experimental results, we conclude that ConBug helps end users to pinpoint faulty cells.