Which Factor Has the Largest Impact Percentage-Wise on Your Credit Score?

Credit scores are calculated by a company called Fair Isaac Corp.--which originated the scoring system--and the Equifax, TransUnion and Experian credit bureaus. The formulas are all similar, and the resulting three-digit numbers tell lenders whether you are statistically likely to pay your bills or default. Your scores come from five different categories of financing information, each of which has a certain percentage of influence on the final number.

Payments

Your payment history on your credit-related accounts has the largest impact percentage-wise on your credit score; FICO advises that it is 35 percent of the total number. Payment history includes monthly payments and related activities like charge-offs for bad debt, court judgments for unpaid bills and bankruptcy cases. On-time payments raise your score, but delinquencies and other negatives reduce it.

Debt

Your debt has nearly as much influence on your credit score as your payment history, accounting for 30 percent of the score. You get your best score when you keep your credit card balances under ten percent of your total available credit, according to MSN Money writer Liz Pulliam Weston. Your score does not take a major hit unless you spend more than 30 percent of your credit lines, and it improves once you pay the balances down.

Time Frame

Your credit-use time frame is not as important to your score as payments and debt load, but it does influence 15 percent of the number, FICO advises. Older accounts with long, positive histories are more helpful to your credit rating than new loans or credit cards, and several long-term accounts are better than one or two. Your credit cards fall off your credit reports in 10 years after you close them, and they do not have as much influence after closure as accounts with recent activity.

Credit

Your new credit accounts and the types of credit you use have a minor influence on your credit score, as each counts for 10 percent. These categories include new accounts for which you have applied, those for which you were approved and how many of your accounts are installment loans or revolving credit. Inquiries based on new applications are important in the new credit category because more than six unrelated credit checks made close together mark you as a high bankruptcy risk, FICO warns. Multiple inquiries generated by rate shopping for major loans like car or home financing count as just one credit check if they happen within 30 days.