Credit Score Explained: What Actually Moves the Number

Your credit score affects the interest rate on your car loan, whether you get approved for an apartment, how much you pay for insurance in some states, and even whether certain employers will hire you. Despite how much rides on this three-digit number, most people have no idea what actually moves it — and a lot of the common advice is flat-out wrong.

Here's how credit scores actually work, stripped of the myths.

The Five Factors (And How Much Each One Matters)

Your FICO score — the one most lenders use — is built from five categories, each weighted differently:

1. Payment History — 35%

This is the biggest factor by far. Have you paid your bills on time? A single 30-day late payment can drop your score 60-100 points, and it stays on your report for 7 years. The more recent the late payment, the harder it hits.

This is also why the most effective way to build credit is the most boring: pay everything on time, every time. Set up autopay for at least the minimum payment on every account you have. Nothing else you do matters if you're missing payments.

2. Credit Utilization — 30%

This is the ratio of how much credit you're using versus how much you have available. If you have a credit card with a $10,000 limit and you're carrying a $3,000 balance, your utilization is 30%.

The general advice is to keep utilization under 30%. The real advice is to keep it under 10% if you want the best possible score. People with 800+ scores typically have utilization in the 1-5% range.

Here's the part that surprises people: utilization has no memory. It only reflects your most recent statement balance. If your utilization is 80% this month and 5% next month, your score adjusts immediately. Unlike late payments, there's no lasting damage — it's a snapshot, not a history.

3. Length of Credit History — 15%

This is the average age of all your accounts. Older is better. This is why closing old credit cards — even ones you don't use — can hurt your score. That card you opened in college with a $500 limit? It might be your oldest account. Close it and your average account age drops, potentially by years.

Keep old accounts open, even if you just charge a small subscription to them once a year to keep them active. The age of your oldest account and the average age of all accounts both matter.

4. Credit Mix — 10%

Scoring models like to see that you can handle different types of credit: revolving credit (credit cards), installment loans (car loans, student loans), and mortgages. Having only credit cards isn't as strong as having credit cards plus an installment loan.

That said, this is only 10% of your score. Don't take out a loan you don't need just to "build credit mix." It's a minor factor that improves naturally over time as you take on different types of financing for things you'd buy anyway.

5. New Credit Inquiries — 10%

Every time you apply for new credit, the lender does a "hard pull" on your report. Each hard pull can ding your score by 5-10 points. Multiple inquiries in a short period look risky to lenders — it suggests you might be desperate for credit.

The exception: rate shopping. If you're applying for a car loan or mortgage at multiple lenders to compare rates, FICO treats all inquiries within a 14-45 day window as a single inquiry. They know you're comparison shopping, not opening 6 different loans. So shop around — just do it within a focused time window.

Myths That Won't Die

"Checking your own credit hurts your score"

No. Checking your own credit is a "soft pull" and has zero effect on your score. Check it as often as you want through Credit Karma, your bank's app, or annualcreditreport.com. In fact, you should be checking at least quarterly to catch errors or fraud.

"Carrying a balance builds credit"

This is the most persistent and most wrong piece of credit advice on the internet. You do not need to carry a balance and pay interest to build credit. Your score benefits from using the card and paying the statement balance in full. Carrying a balance just costs you interest — it doesn't help your score at all.

"Closing a credit card helps your score"

Usually the opposite. Closing a card reduces your total available credit (which increases your utilization ratio) and can reduce your average account age. Both hurt your score. The only reason to close a card is if it has an annual fee you don't want to pay and the issuer won't convert it to a no-fee card.

"You need to be in debt to have good credit"

You need credit accounts, not debt. Having a credit card that you use for normal purchases and pay off in full every month gives you a perfect payment history and low utilization — the two biggest score factors — without paying a cent in interest.

What to Do Right Now

If you want to improve your credit score, the priority order is clear based on the weightings above. First, set up autopay on everything to guarantee on-time payments (35% of your score). Second, pay down credit card balances to under 10% utilization (30% of your score). Those two moves alone address 65% of your entire score.

After that, keep old accounts open, don't apply for credit you don't need, and be patient. Time is the most powerful credit-building tool — an 18-year-old with perfect habits will still have a lower score than a 35-year-old with perfect habits simply because of account age. But the habits are what get you there.