While the Fair Isaac Corporation's exact formula for calculating FICO credit scores is proprietary, scores are composed of payment histories, debt levels, length of credit histories, credit inquiries and mixes of credit, notes About.com. FICO scores are based on information taken from consumers' credit reports and range between 300 and 850, with higher scores indicating better credit.
Payment history contributes 35 percent to a person's FICO credit score, with more recent delinquent accounts having a larger negative impact, states About.com. Late payments, bankruptcies and accounts that have gone to collection all negatively impact credit scores. A person's debt level contributes 30 percent to a FICO score, with higher scores given to people who do not utilize all of their available credit. Long credit histories that give more information regarding spending and payment habits contribute to higher credit scores, and length of credit histories make up 15 percent of FICO scores.
Credit inquiries, which occur when people apply for credit, make up 10 percent of FICO scores, according to About.com. People with more credit inquiries have lower scores, as applications for credit can indicate consumers have financial problems or are accumulating too much debt. People with good mixes of credit types have higher FICO scores than those with one type of credit account, as it demonstrates experience managing debt. Mix of credit contributes 10 percent to FICO scores.