How to Calculate a FICO Credit Score

Your FICO score is a number between 300 and 850, with higher scores representing less risky borrowers to lenders. According to the Fair Isaac Corporation, 90 percent of top lenders use FICO scores as part of their credit decisions each year. There isn't a publicly available formula that allows you to calculate your FICO score on your own. But you can learn what factors are considered, and how each affects your FICO score based on different assigned percentage weights.

Payment History (35 Percent)

The most important factor when it comes to your FICO score is your payment history. This factor examines how you've paid your bills in the past. The more consistently you've paid your bills, the better your score. If you've missed a number of payments, your score suffers. The more recent a late payment or the larger the amount of the payment you missed, the more your score goes down.

Balances Due (30 Percent)

Another significant factor in figuring your credit score is the amount of money you owe. This includes the total amount of debt you have, but also looks at how much you owe relative to your credit limits, how much you owe relative to the original amount of a loan, and the different types of debt you owe. For example, having $50,000 in mortgage debt won't hurt your credit score as much as $50,000 in credit card debt.

How Long You've Used Credit (15 Percent)

The longer you've used credit, the better your credit score. This factor looks at the age of your oldest account (so don't cancel you're oldest card unless you have a good reason!) as well as the average age of your accounts. Opening a new credit card lowers the average age of your accounts. Though this could ding your credit score in the short term, managing the card well increases your score over time.

Types of Credit Used (10 Percent)

Using a variety of credit types, such as credit cards, retail accounts, installment loans, finance accounts and mortgages, improves your credit score, according to the Fair Isaac Corporation. But, it's only 10 percent, so it usually doesn't have a big impact on your credit score unless you don't have much credit history to begin with. Experian, one of the three major credit bureaus, advises against opening new credit accounts that you don't need just to improve your mix of credit.

Recent Inquiries (10 Percent)

The final factor is how much credit you've applied for recently. Your credit report notes how many inquiries you've had in the past two years, but only the inquiries in the past 12 months affect your score, according to the Fair Isaac Corporation. An inquiry occurs every time a creditor pulls your credit report in response to an application you made for credit, such as a new loan, credit card or credit limit increase. The impact on your credit score is larger if you don't have have a long credit history, but the long-term benefits of a line of credit you need and use responsibly more than makes up for the short-term dip in your score.