How credit scores work

Your credit score is a three-digit number that decides the interest rate on your mortgage, car loan, and credit cards. Here's what actually moves it, the five factors that matter, and the myths that don't.

By StevenPG April 17, 2026 Reviewed May 21, 2025 6 min read

Educational content only — not financial, tax, or legal advice.

A credit score is a lender’s shorthand guess at how likely you are to pay them back. The scale runs from 300 (terrible) to 850 (excellent). The difference between a 680 and a 780 on a 30-year mortgage can easily be $50,000 in total interest. That’s not a rounding error — that’s real money left on the table.

There are many scoring models, but two dominate: FICO (used in the majority of lending decisions) and VantageScore (used by most free credit-score apps). The inputs are similar; the specific weights differ slightly. What follows focuses on FICO since it’s what lenders use when it actually matters.

The five factors, by weight

FICO publishes the approximate weights of the components that build your score:

Factor	Weight	What it measures
Payment history	35%	Whether you pay on time
Amounts owed (utilization)	30%	How much of your available credit you’re using
Length of credit history	15%	How long your accounts have been open
Credit mix	10%	Variety of account types (cards, installment loans, mortgage)
New credit	10%	Recent inquiries and newly opened accounts

The ordering matters. Pay on time and keep utilization low, and you’ve addressed 65% of what the score cares about. Everything else is secondary.

Payment history (35%)

A single payment that goes 30 days late can drop a good score by 50–100 points. A collection or charge-off can drop it more. Bankruptcies, foreclosures, and tax liens are the heaviest negative marks and can sit on your report for 7–10 years.

The fix is mechanical: autopay the minimum on every account. You can still pay more manually, but the automatic minimum is your safety net against a missed-login, travel, or forgot-to-schedule mistake. A single forgotten bill is not worth the score damage.

Late payments that are less than 30 days late typically don’t hit your credit report — they just get you a late fee. The 30-day mark is the cliff to avoid.

Amounts owed / utilization (30%)

Credit utilization = (balances owed on revolving accounts) / (total credit limits on those accounts), expressed as a percentage.

If you have one card with a $10,000 limit and carry a $3,000 balance, your utilization is 30%. Scoring models reward lower utilization, roughly in these bands:

Under 10%: best
10–30%: good
30–50%: noticeably worse
Over 50%: significant drag
Over 90%: heavy drag, approaching maxed-out

Utilization is calculated on a per-card and aggregate basis. One card at 90% utilization can hurt even if your overall utilization is low.

Important nuance: the score looks at the balance reported on your statement, not your end-of-month balance. If you pay in full every month but your statement prints a $4,000 balance on a $5,000 limit, your reported utilization is 80%. Two ways to fix this:

Pay the card down before the statement closes.
Ask for a credit limit increase — utilization drops as the denominator grows.

Length of credit history (15%)

Scoring models look at:

The age of your oldest account
The average age of all accounts
How long specific accounts have been open

This is why financial advisors repeat “don’t close your oldest credit card even if you’re not using it.” Closing a 20-year-old card can drop your average age of accounts and remove a piece of your credit limit, hitting utilization too.

If a card has a fee and you don’t want to pay it, call and ask to downgrade to a no-fee version of the same card rather than closing. The account history stays intact.

Credit mix (10%)

FICO likes seeing both revolving credit (credit cards) and installment credit (auto loans, student loans, mortgages). A profile that’s only credit cards, or only installment loans, scores slightly lower than a balanced mix.

That said: do not take out a loan just to improve your credit mix. The cost of interest will vastly exceed the benefit of a few score points. Credit mix takes care of itself over time as you naturally accumulate accounts.

New credit (10%)

When you apply for credit, the lender pulls a hard inquiry, which knocks 3–5 points off your score for about a year and stays on your report for two years. A single inquiry is minor. Five inquiries in three months is a red flag to lenders, not just the score.

Two useful exceptions:

Rate-shopping windows. Multiple mortgage, auto, or student loan inquiries within a 14–45 day window (depending on scoring model) count as a single inquiry. Shop rates aggressively inside the window.
Soft inquiries don’t count. Pulling your own credit, pre-approved offers, and most employer background checks are soft pulls. They don’t affect your score.

Opening a new account also drops your average age of accounts, which is a secondary hit. If you’re about to apply for a mortgage, stop opening new cards for 6–12 months.

What the score does NOT look at

Things people often assume matter but don’t directly affect your FICO or VantageScore:

Income
Employment
Assets or savings
Rent payments (unless specifically reported — most landlords don’t)
Utility and cell phone bills (unless sent to collections)
Debit card usage
Marital status
Race, age, gender

Lenders look at income when making a lending decision, but the score itself doesn’t. A high earner with bad credit still has bad credit.

How to build a score from zero

A common pattern for someone with no credit history:

Get a secured credit card (you deposit $200–500 as collateral). Use it for one small recurring charge, like a streaming subscription. Pay in full monthly.
After 6–12 months, apply for a normal unsecured card. Leave the first one open to preserve account age.
Add a small installment loan when you naturally need one (car, not “credit-builder loan for the credit mix”).
Wait. Length of history is half the battle and it just takes time.

Starting from zero, most people can get into the “good” range (670+) within 12–18 months of consistent on-time payments and low utilization.

How to recover from damaged credit

The two levers that move fast:

Bring utilization under 10%. You can often see a score bump in 30–60 days, because utilization resets every statement cycle.
Dispute errors. Pull your reports free at AnnualCreditReport.com and file disputes on anything wrong. The bureaus have 30 days to investigate.

Late payments, collections, and bankruptcies take years to age off. There is no shortcut. Anyone selling you one is selling fraud.

Checking your score safely

Your credit card issuer probably shows your FICO score for free in the app.
Credit Karma and similar services show VantageScore (free). Useful for trend-watching; not what a mortgage lender sees.
AnnualCreditReport.com is the government-mandated free weekly credit report (not score) from each of the three bureaus. Review at least once a year.

Checking your own credit is a soft inquiry and does not affect your score.