Why are the credit scores that I get from the three major credit report agencies different from the score that a financial institution uses when I apply for a loan? Why are the scores different on all three bureaus' reports even when pulled on exactly the same day? — Curtis S.

The three major credit reporting agencies—Equifax, Experian and TransUnion—use proprietary algorithms to generate your credit score. And your lender may have its own way of crunching credit scores. So even though each credit rating is based on the same information, the numbers from each agency or lender may be slightly different.

"Each agency feels that they have the best way to score and provide risk assessment," says Norm Magnuson, vice president of public affairs at the Consumer Data Industry Association, the credit bureau trade association in Washington, D.C.

Other differences in credit score may arise from discrepancies in your report. Banks and credit bureaus may update that information at different times, although they are required by law to do so once every 30 days. Magnuson says that the difference in timing of an update can lead to variations in your credit score.

— Austin Kilham

Got a question for the Help Desk? Send it to helpdesk@cnnmoney.com.