Before they decide on the terms of your mortgage loan (which they base on their risk), lenders need to find out two things about you: whether you can pay back the loan, and if you will pay it back. To understand your ability to repay, they assess your income and debt ratio. To assess your willingness to pay back the mortgage loan, they consult your credit score.

The most commonly used credit scores are FICO scores, which Fair Isaac & Company, a financial analytics agency, developed. The FICO score ranges from 350 (very high risk) to 850 (low risk). We’ve written a lot more about FICO here.

Your credit score comes from your history of repayment. They never consider your income, savings, amount of down payment, or personal factors like sex ethnicity, nationality or marital status. These scores were invented specifically for this reason. Credit scoring was envisioned as a way to consider solely what was relevant to a borrower’s willingness to repay a loan.

Your current debt level, past late payments, length of your credit history, and other factors are considered. Your score results from both positive and negative items in your credit report. Late payments count against you, but a record of paying on time will improve it.

To get a credit score, borrowers must have an active credit account with a payment history of at least six months. This history ensures that there is sufficient information in your credit to assign an accurate score. If you don’t meet the criteria for getting a score, you may need to establish your credit history prior to applying for a mortgage loan.