You have a lot riding on your credit scores -- your mortgage rate, car payment, credit card interest rates and more -- so it is critical that you know where you stand.

But the score you think you have and the score lenders think you have are two very different things, as Consumer Alert found out.

Most savvy consumers think they have three scores -- one from Experian, one from Equifax and one from TransUnion. But, you really have many more and they all can be very different.

"They're could be hundreds out there," said Walt Wojciechowski, of Experian.

Wojciechowski said that the scores his company gives to lenders is one thing and the score his company gives you is another. It is the same with Equifax and TransUnion.

"Auto lenders have their own scores, insurance companies have their own scores, so there's a variety of scores, there's not just one score," Wojciechowski said.

Why do they all have different scores? Because different lenders care about different things, so credit bureaus make special scoring models just for lenders based on their preferences.

What that means for you is that the Equifax, Experian and TransUnion score you pull is probably different from the Equifax, Experian and TransUnion score a lender pulls.

Consumer Alert had a couple of consumers pull their scores directly from the credit reporting agencies. Then, we took their information to mortgage lender Pat Keenan, of Wells Fargo.

"Wow, that's a big difference. That could effect the decision of the loan," Keenan said.

One consumer pulled a score of 632 from Equifax. But under the mortgage lender's model, her Equifax score was 599.

She also pulled an Experian score of 608. Her Experian score in the lender's office was 583.

Another consumer pulled a score from TransUnion of 625. The lender's TransUnion score was 597.

"It could be the difference between whether you're approved or not and what rate you're going to get," Keenan said.

Next, Consumer Alert took the consumers' information to car dealer Jay Haenn, of Lansdale Chrysler Jeep.

"I've heard of differences of 50 points before," Haenn said.

One consumer pulled an Equifax score of 632, but her Equifax score at the car dealer was 578. That difference could mean a much bigger monthly payment.

"You can have a difference of $100 a month," Haenn said.

The good news is that the car dealer and mortgage lender Consumer Alert used also pulled some scores higher than what the consumer pulled.

The Consumer Alert bottom line is that knowledge is power in this situation. You should know that your score will be one number at one lender and another number at the next. So shop around. If one lender says your score is bad, try another. Another lender may pull a much different number and that could save you big money every month.

Having lenders pull your credit too many times can have a negative effect -- but just a few times won't really hurt.