The growth of the Internet has been accompanied by the growth of web services (e.g. e-commerce, ehealth) leading to the need to protect the personal privacy of web service users. However, it is also important to be able to measure a web service in terms of how well it protects personal privacy. Such a capability would benefit both users and developers. Users would benefit from being able to choose (assuming that such measures were made public) the service that has the greatest ability to protect user privacy (this would in turn encourage web service providers to pay more attention to privacy). Developers would benefit by being able to incrementally measure and modify their services during development until certain target levels of privacy protection are reached. This paper presents an approach for measuring how well a web service protects personal privacy and illustrates the approach with an example.