Exactly how one negative item will affect your credit score is somewhat of a mystery and has been the subject of much criticism of the three main credit bureaus. How a defaulted student loan on your credit report affects your credit score will differ from how it affects your neighbor's credit score. We do know this: A defaulted student loan on your credit report is wreaking havoc on your score. A credit score is comprised of several elements:Payment history - Payment history refers to how you have been paying your bills and installment loans. How often have you missed payments? How long have you let payments fall past due? 30 days? 60 days? More than 180 days? Have any of your creditors written off your balances as bad debt such as the charge off you're concerned about? Have you been sued for payment? Have you also defaulted on a student loan or a car loan? If you have any of these disastrous items on your credit report it's probably time to call a credit counselor and get real about your financial decisions. Amounts owed - This not only refers to the obvious: how much money do you owe your creditors but also how much do you owe in relation to the credit limits on your accounts. Have you reached or exceeded the limit on your credit cards? How many accounts do you have that show unpaid balances? Even if you're paying your bills on time, if you have a large number of bills they could be affecting your credit score negatively and lenders see you as a risk. Length of credit history - How long have been responsible (or irresponsible as the case may be) with credit? Does your credit report show you as being a trust worthy borrower? How about new credit? Have you been applying for lots of credit recently? This also flags lenders that you might be looking to make a number of large purchases or maybe you are short on cash and need to open credit to make ends meet in the short term. There a several scenarios that affect your credit score. No one can tell you exactly how much one defaulted student loan is lowering your credit score but credible credit repair service would know more than anyone. There are a number of terrible consequences of having a student loan in default. A bad credit score is just one of them.