Many different formulas are used to calculate a credit rating but most are based on the following factors:

• Payment history - Basically how you have managed your various payments in the past. Records of late payments on your current and past credit accounts will lower your credit rating.
• Public records - Public records such as bankruptcies, judgments, and collection items may lower your credit rating.
• Amount of money you owe and the amount of available credit - Owing too much will lower your credit rating, especially if you're approaching your total credit limit.
• Length of credit history - Generally a longer credit history is better for a better credit rating.
• New accounts - Opening multiple new accounts in a short period of time may lower your credit rating.
• Searches - Whenever someone else gets your credit report e.g. a lender, landlord, or insurer, a search is recorded on your credit report. A large number of recent searches may lower your credit rating.
• Accounts in use - The existence of too many open accounts can lower your credit rating, whether you're using the accounts or not.