How credit scores actually work

Your credit score decides your interest rate, and your interest rate decides what everything costs. Here is what is publicly known about how the number is built — and what is not.

By Trever Barney

Founder & Writer · About the author · Last reviewed 2026-08-25

A credit score is a number, typically from 300 to 850, that estimates how likely you are to repay borrowed money. It is calculated from the contents of your credit report by a scoring model — most commonly FICO, which lenders use in the large majority of consumer lending decisions.

The exact algorithm is proprietary and has never been published. What is published is the set of categories and their approximate weights, and that is enough to work out where your effort should go.

The five factors and their published weights

35%

Payment history

30%

Amounts owed (utilization)

15%

Length of credit history

10%

New credit

10%

Credit mix

Weights from myFICO, "What's in my FICO Scores?". FICO states these percentages are based on the importance of the categories for the general population, and that for particular groups — for example people who have not been using credit long — the relative importance differs. Bars are scaled relative to the largest factor.

What the score ranges mean

800–850

Exceptional

740–799

Very Good

670–739

Good

580–669

Fair

300–579

Poor

The average U.S. FICO Score is 714 as of Fall 2026 — in the "Good" band. That is context, not a target. What matters is where you sit relative to the thresholds your specific lender prices against, which are usually in 20-point tiers.

Why the score matters in dollars

This is the part worth internalising. Credit score tiers change your mortgage rate, and on a 30-year loan a rate difference compounds into an enormous number. A borrower a couple of tiers down can pay tens of thousands more in interest over the life of the same loan on the same house.

Run your own numbers on the mortgage payment calculator — change only the rate and watch the total-interest figure move. That difference is what your credit score is worth to you.

Reality Check — what nobody selling credit repair will tell you

Credit is one of the most heavily marketed-to areas in personal finance, and most of the marketing is false.

Accurate negatives cannot be removed

No company, at any price, can legally delete accurate information from your credit report. Anything advertising otherwise is selling a service it cannot deliver.

You have many scores

Three bureaus, multiple models, multiple versions. There is no single number to optimise, which is why exact-score prediction is not possible.

Checking your own is free and harmless

Your own checks are soft inquiries with zero score impact. Free weekly reports are available at AnnualCreditReport.com — the official, federally mandated source.

Time does most of the work

Payment history and account age are 50% of the score combined, and both are governed almost entirely by the passage of time.

Errors are common and worth disputing

Disputing genuine inaccuracies is free and is the one form of legitimate "credit repair" that exists. You do it directly with the bureaus.

Go deeper

What helps and what hurts

Every meaningful action ranked by impact and speed — plus the myths, named.

Credit utilization explained

30% of your score, and the only part you can change this month.

Credit Score Factor Estimator

Model the five factors against your own situation and see which lever is biggest.

Frequently asked questions

What are the five credit score factors?

FICO publishes five categories and their approximate weights: payment history (35%), amounts owed (30%), length of credit history (15%), new credit (10%) and credit mix (10%). FICO notes these percentages are for the general population and that the importance of each category varies from person to person.

What is a good credit score?

On the standard 300–850 FICO range, 670–739 is considered Good, 740–799 Very Good, and 800+ Exceptional. Below 670 is Fair, and below 580 is Poor. The average U.S. FICO Score is 714 as of Fall 2026.

How long does it take to improve a credit score?

It depends entirely on which factor is holding you back. Utilization can improve within one billing cycle, because balances re-report monthly. Hard inquiries mostly stop affecting FICO scores after 12 months. Late payments and collections take years to fade, and accurate ones cannot be removed early by anyone.

Why is my score different on different sites?

Because there is no single score. Scores differ by bureau (Experian, TransUnion, Equifax), by model (FICO vs VantageScore), by model version, and by industry-specific variant. A mortgage lender typically pulls older FICO versions that can differ noticeably from the free score in a banking app.

FICO® is a registered trademark of Fair Isaac Corporation. NumberPond is not affiliated with, endorsed by, or connected to Fair Isaac Corporation or any credit bureau.

No third party can predict your exact FICO® or VantageScore change. This tool illustrates the published direction and relative weight of scoring factors — it is an educational model, not a score prediction. For a simulation run against your real credit file, use your card issuer’s or credit bureau’s own simulator.

Sources

What's in my FICO Scores? — myFICO (Fair Isaac Corporation) · accessed 2026-08-25
What is a FICO Score? — myFICO (Fair Isaac Corporation) · accessed 2026-08-25
FICO Score Credit Insights (national average 714) — FICO · Fall 2026 · accessed 2026-08-25
What is a credit score? — Consumer Financial Protection Bureau · accessed 2026-08-25
Free credit reports — AnnualCreditReport.com — Consumer Financial Protection Bureau · accessed 2026-08-25