Your credit score is a three-digit number that lenders use to decide whether to approve you, at what interest rate, and on what terms. Most people know it matters. Far fewer understand exactly how it is calculated. That gap costs money: if you do not know which factors move your score, you cannot optimize for them.
FICO scores, which are used in the vast majority of lending decisions in the United States, are calculated using five factors. Those factors are not equally weighted. Understanding the weight of each one, and what actions actually move the needle, is the foundation of any serious credit-building strategy.
Factor 1: Payment History (35%)
Payment history is the single largest factor in your FICO score, accounting for 35% of the total. This measures whether you have paid your accounts on time: credit cards, loans, mortgages, and even some utility and phone bills depending on which credit bureau is reporting them.
A single missed payment can drop your score significantly, and the drop is larger if your score was high to begin with. A 30-day late payment on a score of 760 can knock off 90 to 110 points. The same missed payment on a score of 620 may only cost 60 to 80 points. FICO penalizes those who have the most to lose.
The good news: payment history is also the factor that recovers fastest through consistent positive behavior. Paying on time, every month, without exception, is the single highest-leverage action you can take for your credit score. Set every account to autopay at minimum payment to eliminate accidental lates entirely. You can always pay more manually, but the autopay floor prevents the catastrophic misses.
Late payments stay on your credit report for seven years from the date of first delinquency. However, their impact on your score fades significantly over time. A late payment from four years ago hurts far less than one from four months ago.
Factor 2: Credit Utilization (30%)
Credit utilization is the second-largest factor and the fastest-moving lever in the entire scoring model. It represents the percentage of your available revolving credit that you are currently using: your total credit card balances divided by your total credit limits.
If you have three credit cards with a combined limit of $20,000 and a combined balance of $8,000, your utilization is 40%. FICO rewards low utilization. Scores in the 760 to 850 range typically carry utilization well below 10%. The commonly cited threshold of 30% is a floor to stay below, not a target to aim for.
Utilization is calculated at the time your lender reports to the bureaus, which typically happens once per month, around your statement closing date. This means that if you pay your balance down before the statement closes, your reported utilization drops even if you had spent heavily during the month. High utilization followed by a full payoff before the statement date effectively reports as zero utilization.
Utilization changes every month and responds quickly to actions. Paying down a $5,000 balance on a $10,000-limit card from 50% to 10% can move your score 20 to 40 points in a single cycle. This makes utilization the most actionable short-term lever for people who need to improve their score before a major application. For a full debt payoff strategy that also improves utilization, see our guide on how to prioritize which debts to pay first.
Factor 3: Length of Credit History (15%)
Credit history length accounts for 15% of your FICO score. FICO looks at three sub-components: the age of your oldest account, the age of your newest account, and the average age of all your accounts combined.
Older accounts help your score; new accounts hurt it, at least temporarily. This is why closing an old credit card, even one you rarely use, can ding your score: it reduces the average age of your accounts and eventually removes a long history from your report when it ages off (which happens 10 years after closing for accounts in good standing).
The practical implication: do not close old credit cards unless there is a compelling reason to do so, such as a high annual fee you cannot justify. Keep them open with a small recurring charge and autopay. A card you use once a year for a streaming subscription and pay automatically is building your history with zero effort.
New credit applications also reduce your average account age. Opening five new accounts in a short period compresses your average age significantly and signals elevated risk to lenders. Spread out applications over time when possible.
Factor 4: Credit Mix (10%)
Credit mix accounts for 10% of your score and measures the variety of credit types you carry. FICO rewards borrowers who can manage multiple types of credit responsibly: revolving accounts (credit cards), installment loans (auto loans, personal loans, mortgages), and other account types.
Having only credit cards and no installment loans, or only installment loans and no revolving credit, leaves points on the table. Adding a credit builder loan or a secured credit card when you only have one type of account can provide a modest boost.
That said, 10% is not enough weight to justify opening new accounts purely to improve your mix. Do not take on debt you do not need. The gain from mix improvement rarely outweighs the cost of a new hard inquiry and the reduction in average account age. Credit mix is a secondary consideration, not a primary strategy.
Factor 5: New Credit Inquiries (10%)
New credit accounts for the remaining 10% of your FICO score. It measures how frequently you have applied for new credit recently, tracked through hard inquiries on your report. Each hard inquiry from a credit application can temporarily reduce your score by 5 to 10 points.
FICO treats rate-shopping for auto loans, mortgages, and student loans with some flexibility: multiple hard inquiries for the same loan type within a 14 to 45-day window (depending on the FICO version) count as a single inquiry. This allows you to shop lenders without each application hammering your score separately.
Hard inquiries stay on your credit report for two years but only affect your score for the first 12 months. A cluster of applications from three years ago has zero impact on your current score. Soft inquiries, such as when you check your own credit or when lenders pre-screen you for offers, never affect your score.
How the Factors Interact
The five factors do not operate in isolation. A thin file, meaning few accounts and short history, is scored differently than a thick file with years of data. Someone with two accounts and no late payments may score lower than someone with ten accounts and one minor late payment, because FICO has less data to work with on the thin file and assigns higher uncertainty.
The fastest path to score improvement combines two things: fixing what is dragging the score down, usually utilization and any recent lates, and building positive history consistently over time. There is no shortcut that skips the time component. You can move your score 30 to 60 points in 60 to 90 days by paying down balances and correcting errors. Getting from 640 to 760 reliably takes 12 to 24 months of clean payment history and managed utilization.
The CFPB’s credit score resources provide a free, authoritative reference for understanding how scoring models work and what your rights are when reviewing your report. You are entitled to one free credit report from each of the three bureaus every year at AnnualCreditReport.com, and since 2020 the bureaus have offered free weekly reports through the same portal.
Your Action Plan by Factor
Ranked by the leverage each action provides:
- Payment history (35%): Set autopay on every account at the minimum. Never miss a payment for any reason.
- Utilization (30%): Pay down credit card balances. Target below 10% on each card, not just overall. Request credit limit increases on cards in good standing to expand available credit without carrying more debt.
- History length (15%): Keep old accounts open. Do not close paid-off cards unless the fee is unjustifiable.
- Credit mix (10%): Do not open new accounts purely for mix. Let this improve naturally as you add account types for legitimate reasons.
- New inquiries (10%): Limit applications to when you actually need credit. When rate shopping for a mortgage or auto loan, do it within a 2-week window.
Once your score is in a healthy range, pairing it with a clear debt payoff strategy maximizes the financial benefit. Lower scores mean higher rates on everything from mortgages to car loans to credit cards. Even a 50-point improvement can save thousands over the life of a loan. Our guide to the personal loan vs balance transfer card comparison shows how your score directly affects which debt payoff tool is available to you, and at what cost.
If your report contains errors dragging your score down, disputing them is the highest-ROI action available before any payoff strategy. The NFCC offers free credit counseling to help you interpret your report and build a realistic improvement plan.