What a Credit Score Actually Measures

A FICO score, the most widely used model, runs from 300 to 850 and is calculated purely from what's on your credit reports: accounts, balances, and payment history. It says nothing about your income, your savings, or your character — only about patterns in borrowing and repaying that have historically predicted whether someone pays back what they owe.

Two people earning the same salary, with the same savings, can carry very different scores — because the score never sees the salary or the savings. It only sees what shows up on a credit report: how many accounts, how old, how full, and how reliably paid. A person with no credit history at all doesn't score badly; they score nothing, because there's no pattern yet to predict from.

Select a factor below to see what it actually measures. Notice how lopsided the weights are — the top two factors alone account for 65% of the score, and both are things you have direct, ongoing control over.

“Amounts owed,” the second-heaviest factor at 30%, is mostly one number: credit utilisation — the balance on a card divided by its credit limit, expressed as a percentage. A $1,500 balance on a $5,000 limit is 30% utilisation. The same limit carrying $500 is 10%. The same limit carrying $4,200 is 84%, and it doesn't matter that the card gets paid off in full every month — the number the score sees is whatever balance was reported.

30% is the widely quoted ceiling, but it isn't a threshold you cross safely below and fail above. Utilisation scores on a curve — the excellent range is closer to 10%, and every step down from there helps a little more, not just the step across 30%. Utilisation is also calculated two ways at once: per card, and across every card combined, so one maxed-out card can drag the score down even while the rest sit near zero.

Most issuers report a balance to the credit bureaus once a month, on or near your statement closing date — not the due date, and not whatever the balance happens to be today. Pay your card off in full a week after the statement closes, exactly as this track's credit card lesson recommends, and the balance that already got reported was the pre-payment number, sitting on your credit report until next month's statement replaces it.

This is why someone with a spotless payment history can still see a utilisation-driven dip before a mortgage or car loan application — heavy spending in the weeks before the statement closed got reported at its peak, even though it was paid off in full days later. The fix, if a big application is coming up, is to pay down the balance before the statement closes, not just before the due date.

The scale is asymmetric. A single payment 30 days or more late can drop a good score by 60 to 100 points and stay on your report for seven years. Paying a card off a week early instead of on the due date does essentially nothing extra for your score — on-time is on-time. The lesson isn't to pay early; it's that avoiding a single late payment is worth more than almost anything else on this list.

Negative marks don't all persist for the same length of time, and the difference matters for how urgently to fix each one.

Two beliefs about credit scores are common, confidently repeated, and wrong. Both lead people to either waste money or avoid a useful habit out of caution that isn't earned — and the second one clears up once you know what actually does count as a hard pull.