http://jobfunctions.bnet.com/abstract.aspx?docid=388807&promo=100511
You can use this tool to figure out if you might be at risk of being denied a loan.
In general, lenders apply certain rules when evaluating someone that has applied for credit. In the mortgage industry, they use a rule of 32 which states that the total of all your monthly debt payments cannot exceed 32% of your monthly income.
When debt ratios approach 40%, the chances of you being denied credit or a loan are high.