Credit & Debt

How Credit Scores Are Calculated: The 5 Factors That Actually Matter

A clear, in-depth breakdown of how FICO and VantageScore models weigh your payment history, utilization, account age, new credit, and credit mix — and what each factor really means for your score.

By Pier Zam·Published April 10, 2026·Updated April 28, 2026·12 min read

Illustration of a credit score gauge dial with the needle pointing toward the high range

Most people know their credit score matters, but very few know what actually moves it. The score itself is just a three-digit shorthand — between 300 and 850 in the FICO model — that tries to predict how likely you are to repay borrowed money over the next 24 months. Behind that single number sits a model with five weighted inputs, each pulling your score up or down for very different reasons.

Understanding those inputs is what separates people who guess at credit ("maybe I'll close this card?") from people who actually steer it. This guide walks through each of the five factors, what the data shows about how they interact, and where popular advice gets it wrong.

The two main scoring models: FICO and VantageScore

When a lender pulls your credit, they almost always get a FICO Score (used in roughly 90% of U.S. lending decisions according to FICO's own published data) or a VantageScore (more common in free credit monitoring tools like Credit Karma). Both score from 300 to 850, both pull from the same three credit bureaus — Equifax, Experian, and TransUnion — and both weigh similar behaviors, but they don't produce identical numbers.

It's normal to see a 20–60 point spread between the FICO score your mortgage lender uses and the VantageScore on a free app. Neither is "wrong"; they just weight inputs differently. The factors below describe the classic FICO 8 model, which is still the most widely used.

Factor 1: Payment history (35% of your score)

Payment history is the single biggest lever, and it's also the slowest to recover. The model is essentially asking: when you've borrowed money in the past, did you pay it back on schedule?

What counts as a negative event:

30-, 60-, 90-day late payments reported by a creditor. The longer the delinquency, the bigger the hit.
Charge-offs (the lender writes the debt off as a loss, usually after 180 days unpaid).
Collections accounts.
Public records like bankruptcies and certain judgments.

A single 30-day late payment on a previously perfect file can drop a 780 score by 80–110 points, according to FICO's research published in The myFICO Loan Center. Most negative items stay on your report for seven years (Chapter 7 bankruptcy stays for ten). They lose weight over time, but they don't disappear early.

What this means in practice: automate at least the minimum payment on every account. The model does not give partial credit for paying "most" of the bill on time — a 30-day late is a 30-day late whether you owed $40 or $4,000.

Factor 2: Amounts owed / credit utilization (30%)

This factor is mostly about credit utilization: how much of your available revolving credit (credit cards and lines of credit) you're using on the day each statement closes. Installment loans like mortgages and auto loans are treated separately and matter much less here.

The math is simple. If you have one credit card with a $5,000 limit and your statement closes with a $1,500 balance, your utilization is 30%. If you have three cards totaling $15,000 in limits and a $1,500 combined balance, your overall utilization is 10% — a much better signal to the model.

Generally accepted utilization tiers:

1–9%: ideal range for high scores.
10–29%: healthy.
30–49%: the model starts to worry.
50%+: noticeable score drag.
90%+: a clear red flag.

Two important nuances:

Per-card utilization matters too. Maxing out one card while leaving others empty is worse than spreading the same balance across several cards.
Utilization has no memory. Unlike payment history, last month's 80% utilization stops mattering as soon as your next statement reports a low balance. This is why utilization is the fastest factor you can move.

Factor 3: Length of credit history (15%)

The model looks at three things here: the age of your oldest account, the age of your newest account, and the average age across all accounts. Older is better. This is the factor most damaged by closing your first credit card too early.

An important detail: closed accounts in good standing usually stay on your credit report for about 10 years and continue to contribute to your average age during that window. After they fall off, your average age can drop sharply, which is why people sometimes see a strange score dip a decade after closing a card.

What this means in practice: if your oldest card has no annual fee, keep it open and use it once a quarter for a small purchase to keep the issuer from closing it for inactivity.

Factor 4: New credit (10%)

Every time you apply for credit and the lender pulls your full report, that's a hard inquiry. A single hard inquiry typically costs a few points and fades within 12 months. Several hard inquiries in a short period — especially across different credit types — are read as financial stress.

Two protections built into the model:

Soft inquiries (checking your own score, pre-approved offers, employer checks) do not affect your score at all.
Rate-shopping windows. When you apply for multiple mortgages, auto loans, or student loans within a short window (14–45 days depending on the FICO version), they're typically grouped as a single inquiry. Credit card applications are not grouped this way.

Factor 5: Credit mix (10%)

The model rewards borrowers who have successfully managed more than one type of credit — typically a blend of revolving (credit cards) and installment (auto loan, mortgage, student loan, credit-builder loan). It's a small factor, and it's not worth taking on a loan you don't need just to "improve your mix." But over time, a healthy mix gives the model more data to work with.

The 5 factors at a glance

Factor	FICO weight	How fast it moves	Biggest lever
Payment history	35%	Slow (years)	Autopay every minimum, every month
Amounts owed (utilization)	30%	Fast (1 statement cycle)	Pay before the statement closes
Length of credit history	15%	Very slow (years)	Keep oldest no-fee card open and active
New credit	10%	Medium (~12 months)	Avoid clusters of hard inquiries
Credit mix	10%	Slow (months–years)	Blend revolving + installment over time

Putting it together: the order of operations

If you're trying to move a score deliberately, the factors don't all respond on the same timeline:

Days, not months: lowering utilization. Pay down balances before the statement closes.
Weeks to months: a single hard inquiry fading.
Months to a year: a new account aging into a positive contribution.
Years: recovering from a serious delinquency, charge-off, or bankruptcy.

Common myths the model does not actually care about

Your income. Not part of the score.
Your savings or net worth. Also not part of the score.
Carrying a small balance "to build credit." A persistent myth. Statement balances of $0 still report account activity and on-time payments.
Checking your own score. Always a soft pull. Never affects your score.
Debit card use. Has no effect — debit cards do not report to credit bureaus.

Keep reading

If your score is being held back by past delinquencies or high balances, our six-month plan to fix bad credit walks through exactly what to do, in order.
For the foundational mechanics behind the score those accounts feed, see how credit scores are calculated.
Browse every guide on this topic on our Credit & Debt hub.

The bottom line

Your credit score is a model, not a moral judgment. It rewards one thing above all else: a long, boring history of on-time payments with low utilization. If you only remember two rules — pay every bill on time and keep statement balances under 10% of your limits — you'll outrank the majority of consumers without ever thinking about credit "hacks."

Frequently asked questions

Q.What is the most important factor in my credit score?

Payment history. In the FICO 8 model it accounts for roughly 35% of the score, more than any other single input. A single 30-day late payment on a previously clean file can drop a high score by 80–110 points and stays on the report for up to seven years.

Q.What's the difference between FICO and VantageScore?

Both score from 300 to 850 using data from Equifax, Experian, and TransUnion, but they weight inputs differently. FICO is used in roughly 90% of U.S. lending decisions; VantageScore is more common in free credit-monitoring apps. A 20–60 point spread between the two is normal — neither is 'wrong'.

Q.Does carrying a small balance help my credit score?

No. This is one of the most persistent credit myths. Statement balances of $0 still report account activity and on-time payments. Carrying a balance only generates interest charges; it does not build credit faster.

Q.Does checking my own credit hurt my score?

No. Checking your own score (or having an employer check it, or receiving a pre-approved offer) is a soft inquiry and has no effect on your score. Only hard inquiries from new credit applications affect it, and even those typically cost only a few points and fade within 12 months.