Humour is valued by people for its many positive social functions, which is also of great merit for computing exploration. Especially in this era, many advanced computing science and technologies allow new perspectives to address this topic. Among them, creative computing, which aims to offer new and surprising computing solutions, can lend its theoretical and technical supports to humour generation and exploitation. Based on it, the proposed research first raises the concept of the humour degree to bridge the more qualitative topic of humour with the quantitative nature of computing, so as to build a new basis for the following computing work. Secondly, a creative system is designed to calculate the humour degree for utterances. Thirdly, the experiment is conducted to validate the effectiveness of the system. The results show that it is feasible and significant to calculate the humour degree for utterances through a creative computing approach.