A credit rating score is a specific number arrived at by compiling various personal and public financial information. Included are such things as personal data provided by you on a credit application form as well as your payment history, past credit history and other credit-related data. The most common formula or method used to calculate your score is the Fair Isaac Corporation, fondly known as FICO. There are also, however, other methods to determine your credit rating score, including the 9-point credit rating scale. The credit rating score is a collaborative effort between creditors and credit agencies. A lender uses this information to decide whether or not to give you a loan, grant you a service or provide you with a credit card. The numbers of a credit rating score usually range between 300 and 800. A higher number indicates a good credit rating score; a low number reveals a poor or bad credit rating score.