Credit Score Factors Explained: What Actually Goes Into Your FICO Score

    By CreditKaren Editorial Team··8 min read

    AI-assisted drafting, human-reviewed and source-checked before publication — how we create content.

    Your credit score isn't a mystery — it's a weighted formula. Knowing exactly what goes into it (and how much each input matters) lets you focus your effort on the moves that actually shift the number. This guide breaks down each FICO and VantageScore factor with realistic examples.

    Payment history (35%)

    The single biggest factor. A 30-day-late payment can drop your score an amount that varies by scoring model and credit file and stays on your report for 7 years. The good news: a single late after years of on-time payments hurts much less than chronic delinquency, and the impact fades over time.

    Set autopay for at least the minimum on every account. The fastest way to lose an amount that varies by scoring model and credit file is to miss one payment by 30 days.

    Credit utilization (30%)

    Utilization is the percentage of your revolving credit you're using. Calculated per-card and overall. Under 30% is good; under 10% is excellent; 0% is slightly worse than 1–9% (the score wants to see you using credit responsibly, not avoiding it).

    Utilization is the fastest-moving factor. It updates with each statement cycle, so changes show up in 30 days.

    Length of credit history (15%)

    Calculated from the age of your oldest account, your newest account, and the average age across all accounts. This is why closing your oldest credit card almost always hurts — even if you never use it.

    If you have a thin file, becoming an authorized user on a parent's or spouse's well-aged account can add years of history to your report.

    Credit mix (10%)

    FICO rewards a mix of revolving credit (credit cards) and installment loans (mortgage, auto, student, personal). If you only have credit cards, adding a small credit-builder loan can produce an amount that varies by scoring model and credit file over a few months.

    New credit / inquiries (10%)

    Hard inquiries may affect certain credit scores, but the effect varies by scoring model and individual credit history. Multiple mortgage or auto loan inquiries within a 14–45 day window are bundled as one, so rate-shopping doesn't compound.

    Soft inquiries (checking your own credit, pre-approval offers) don't affect your score at all.

    FICO vs. VantageScore: how the factors compare

    FactorFICO 8 WeightVantageScore 4.0 Weight
    Payment history35%Extremely influential (~40%)
    Credit utilization / total balances30%Highly influential (~20%)
    Length of credit history15%Less influential (~21% combined with mix)
    Credit mix & types10%Highly influential
    New credit / inquiries10%Less influential (~5%)
    Available creditNot directLess influential (~3%)
    Score range300–850300–850
    Used byMost lenders, all major mortgageFree credit monitoring services

    Frequently asked questions

    Payment history is the largest single factor at 35% of your FICO score, followed by credit utilization at 30%. Together these two factors account for 65% of your score, which is why most credit improvement advice focuses on paying on time and keeping balances low.

    Under 30% is considered good, under 10% is excellent. The lowest scores in this category go to consumers using 80%+ of their available credit. A utilization of 0% is slightly worse than 1–9% because the FICO model rewards demonstrated responsible use, not avoidance.

    Hard inquiries may affect certain credit scores, but the effect varies by scoring model and individual credit history. Multiple mortgage, auto, or student loan inquiries within a 14–45 day window are bundled as a single inquiry for scoring purposes, so rate-shopping doesn't compound.

    VantageScore uses the same 300–850 range as FICO but weights factors differently. Payment history is classified as 'extremely influential' (~40%), while inquiries are 'less influential' (~5%). FICO uses 35% / 30% / 15% / 10% / 10%. Most mortgage lenders use FICO 2/4/5; free credit monitoring apps usually show VantageScore 3.0 or 4.0.

    FICO scores range from 300 to 850. The tiers are: Poor (300–579), Fair (580–669), Good (670–739), Very Good (740–799), and Exceptional (800–850). A score of 670 or above generally qualifies for mainstream credit products at competitive rates.

    Mortgage lenders are required to use FICO 2/4/5 (older models specific to each bureau). Most credit card issuers use FICO 8 or FICO 9. Auto lenders use FICO Auto Score 8 or 9. Free apps like Credit Karma display VantageScore 3.0, which most lenders do not use for approval decisions.

    The two models weight factors differently, treat collections differently (VantageScore ignores paid collections; FICO 8 does not), and have different minimum scoring requirements. If one bureau reports an account the others don't, or reports a different balance, that alone can create a 30–60 point gap.

    There are dozens of scoring models in use. A mortgage lender may pull FICO 2/4/5 while your credit card issuer uses FICO 9. Each of the three bureaus may hold slightly different data, and the score is only as accurate as the underlying report. Differences of an amount that varies by scoring model and credit file across sources are completely normal.

    No single bureau is most important — lenders pull different bureaus depending on your location and the product type. Auto lenders often favor Equifax, mortgage lenders pull all three, and credit card issuers vary by bank. You should monitor all three because errors on any one bureau can cost you the best rates.

    Conventional loans typically require a 620 minimum. FHA loans accept scores as low as 580 with 3.5% down, or 500–579 with 10% down. A score of 740+ generally unlocks the best mortgage rates. Lenders use the middle score of your three FICO 2/4/5 scores, not the highest.

    What to gather first

    • A current copy of each credit report you want to review (Equifax, Experian, TransUnion) from AnnualCreditReport.com.
    • Government-issued photo ID and proof of current address, which bureaus commonly request with a mailed dispute.
    • Account statements, payment records, or letters that relate to the item you believe is inaccurate or incomplete.
    • The exact account name, partial account number, and the reason you believe the entry is inaccurate or incomplete.
    • A way to keep records: copies of what you send and, if mailing, proof of delivery.

    Common mistakes to avoid

    • Disputing information you know is accurate — that wastes the process and does not help you.
    • Sending a vague dispute. Identify the specific item and explain what is inaccurate or incomplete.
    • Disputing with only one bureau when the same entry appears on more than one report.
    • Keeping no copies of what you sent, so you cannot show what was disputed or when.
    • Paying a company that promises deletions or score increases — no one can promise those outcomes.

    When to get additional help

    Consider additional help if a bureau or furnisher does not respond, if an entry you believe is inaccurate stays on your report after a reinvestigation, if you may be affected by identity theft, or if you have questions about your legal rights.

    How CreditKaren can help

    CreditKaren is a free, AI-assisted tool that reviews a credit report you upload and highlights entries that may be inconsistent, incomplete, or worth a closer look. If you decide an item may be inaccurate or incomplete, CreditKaren can draft a dispute letter you can review, edit, and send yourself.

    CreditKaren is not a law firm, credit bureau, lender, or credit-repair organization. It does not provide legal advice and does not guarantee deletions, dispute outcomes, or changes to your credit scores. You decide what to dispute and you send every letter.

    Important limitation

    Credit reporting disputes should be based on information you believe may be inaccurate, incomplete, unfamiliar, or improperly reported. Do not dispute information you know is accurate. A dispute does not guarantee a deletion, correction, score change, or other result.

    Sources and further reading

    Review your own credit report with CreditKaren

    Use CreditKaren's AI-assisted educational tool to organize report entries you may want to investigate for accuracy. You review every result and decide whether to take action.

    CreditKaren does not provide legal, financial, lending, or credit-repair advice. No dispute, deletion, score increase, approval, or other outcome is guaranteed.

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    Who wrote this & how we work

    This page is maintained by CreditKaren to answer common questions about the Fair Credit Reporting Act and our free AI-assisted educational credit report review tool. It reflects current practices in the app and is not legal or financial advice.