How Credit Scores Are Calculated: 5 Key Factors

Your credit score is a three-digit number between 300 and 850 that lenders use to decide if they'll give you money. The higher your score, the better your chances of getting approved for loans, credit cards, and lower interest rates.

Here's what the ranges mean in real terms:

300-579: Bad credit. You'll face rejection from most lenders or get approved with very high interest rates (10%+ on personal loans, 20%+ on credit cards).

580-669: Fair credit. You can get approved for some products, but interest rates will be 5-10% higher than someone with good credit.

670-739: Good credit. You qualify for most loans and cards at reasonable rates.

740-799: Very good credit. You get approved quickly with competitive rates.

800-850: Excellent credit. You get the best rates available.

Your score gets calculated by three major credit bureaus—Equifax, Experian, and TransUnion—using information from your credit report. These reports track your payment history, debts, and how long you've had credit accounts. Under the Fair Credit Reporting Act (FCRA), you're entitled to one free credit report per year from each bureau at AnnualCreditReport.com. Check yours now to see what information is being used to calculate your score.

Payment history is the single biggest factor in your credit score, worth 35% of the total. This is straightforward: Did you pay your bills on time?

What counts: Credit cards, auto loans, mortgages, student loans, medical bills sent to collection, and utility payments (sometimes).

What doesn't count: Rent payments (unless reported to credit bureaus), insurance, phone bills, or taxes.

Here's how it breaks down:

On-time payments: Add points. Every month you pay on time, you're building your score.

30 days late: Costs you 100+ points. A single late payment on a $5,000 credit card balance can drop your score 50-100 points depending on your other factors.

60 days late: Costs you 150+ points.

90+ days late: Costs you 200+ points and stays on your report for 7 years from the original delinquency date.

Collections: Costs you 150+ points and signals serious default.

What matters: The more recent the late payment, the more damage it does. A late payment from 6 months ago hurts more than one from 2 years ago. If you missed a payment, call the lender immediately. Under the FDCPA (Fair Debt Collection Practices Act), debt collectors cannot harass you, call before 8am or after 9pm, or contact you at work if your employer prohibits it. If you pay within 30 days, many lenders won't report it to the bureaus. Even if they do, you can request a goodwill deletion by writing a letter explaining your situation.

Credit utilization is the percentage of available credit you're using. It accounts for 30% of your score—the second most important factor.

Here's the math: If you have a $2,000 credit card limit and a $1,000 balance, your utilization is 50% ($1,000 ÷ $2,000).

Ideal range: Keep utilization under 10% for maximum score benefit. This signals you can borrow money without maxing out.

What happens at different levels:

Under 10%: Excellent. +50-100 points compared to someone at 30%.

10-30%: Good. Minimal damage, still shows responsible borrowing.

30-50%: Fair. Starts to lower your score noticeably.

50%+: Bad. Every percentage point over 50% costs you 5-10 points.

99-100%: Maxed out. Costs you 150+ points and signals financial stress.

Real example: Sarah has three credit cards with $5,000, $3,000, and $2,000 limits (total $10,000). She carries $4,500 total in balances across the cards. Her utilization is 45%. To get below 30%, she needs to pay down to $3,000. She should prioritize paying down her highest-utilization cards first.

Action steps: Ask credit card companies to increase your limits without a hard inquiry—this lowers utilization instantly without new debt. If they won't, open a new card strategically (one hard inquiry costs 5-10 points temporarily, but increases available credit). Pay balances in mid-cycle, not just at the statement date. Bureaus report balances on your statement date, so paying $500 before that date shows as lower utilization even if you charge it back up later.

Age of credit accounts (also called credit history length) makes up 15% of your score. This factor rewards people who've responsibly managed credit over time.

What gets measured: The average age of all your accounts, plus the age of your oldest account.

Why it matters: Lenders see longer credit history as lower risk. Someone with a 15-year-old account demonstrates they can keep accounts open and in good standing.

Real numbers:

Under 1 year: You're brand new to credit. Score might be 500-600 even with perfect payments.

1-3 years: Building history. Score can reach 650-700 with good habits.

5+ years: Established history. Opens doors to better rates.

10+ years: Excellent longevity. This significantly boosts your score.

The average age calculation: If you have four cards opened in 2020 (6 years old), 2019 (7 years old), 2015 (11 years old), and 2023 (3 years old), your average age is 6.75 years.

Critical action: Do not close old accounts. This is the #1 mistake people make. When you close an old account, it stops aging, and your average account age drops. If you closed that 11-year-old card above, your average age would drop to 5.3 years, costing you 20-30 points.

What to do instead: Keep old accounts open even if you're not using them. Make small charges occasionally to keep them active. Never leave them completely dormant or creditors may close them. If you have high annual fees, call and ask for a waiver or downgrade to a no-fee version. If a card has been closed by the creditor, it stays on your report for 10 years and continues to benefit your score.

Credit mix is the variety of credit types you have. It accounts for 10% of your score and shows lenders you can manage different kinds of credit responsibly.

Types of credit that count:

Revolving credit: Credit cards, home equity lines of credit (HELOC), personal lines of credit. You can borrow, repay, and borrow again.

Installment credit: Auto loans, personal loans, student loans, mortgages. You borrow a lump sum and pay it back over time with fixed payments.

Impact on your score:

Only credit cards (revolving): Limited mix. Score penalty of 20-40 points.

Mix of revolving and installment: Ideal. No penalty; actually helps if done responsibly.

Real example: Marcus has two credit cards ($3,000 combined balance) and an auto loan ($8,000 balance). He has good mix—revolving and installment. Compare that to Lisa, who only has credit cards and no loans. All else equal, Marcus's score could be 30 points higher purely from credit mix.

Important caveat: Do not take out loans just to improve your mix. The new account will temporarily lower your score due to the hard inquiry (5-10 points) and reset the age of your oldest account's average. This is only worth it if you actually need the credit and the score improvement pays off in better rates.

What to do: If you only have credit cards, consider a small personal loan or car loan when you legitimately need one. If you only have installment loans, a credit card can diversify your mix. Avoid having too many accounts of one type, especially if you have high balances on all of them—this signals you may be over-leveraged.

Hard inquiries (also called hard pulls) happen when you apply for credit. They make up 10% of your score and are the least damaging factor, but still worth understanding.

Hard inquiry vs. soft inquiry:

Hard inquiry: Counts against your score. Happens when you apply for a credit card, auto loan, mortgage, personal loan, or apartment lease. It means a lender is checking your creditworthiness. Each hard inquiry costs 5-10 points.

Soft inquiry: Does not affect your score. Happens when you check your own credit, a creditor reviews your account, or a company pre-screens you for offers.

Key facts:

Multiple inquiries in short time: Not as bad as you think. Applying for multiple credit cards within 14 days counts as one inquiry for scoring purposes. The system assumes you're shopping around for the best rate. Same with auto or mortgage shopping—multiple inquiries within 45 days usually count as one.

Inquiries fall off after 12 months: After one year, they stop affecting your score. After two years, they disappear from your report entirely.

Real impact: If your score is 720 and you apply for three credit cards in one week, you might drop to 705-710 temporarily. This recovers within 3-6 months as you establish new accounts and build payment history.

What NOT to do: Don't apply for multiple accounts just to shop around for the best rate. Each unnecessary application costs points. Instead, ask lenders if they can pre-qualify you with a soft inquiry—many will.

What to do: Be selective about applications. Before applying, check if you qualify by asking about minimum credit score requirements. Don't apply for store credit cards just to get 10% off today—the hard inquiry cost is not worth the discount. Space out applications by at least a month if possible. When you do need credit, apply within your shopping window (14-45 days) to minimize inquiry impact.

Now that you understand how scores work, here's your concrete action plan based on where you're starting:

If your score is below 580 (Bad Credit):

Month 1: Get your free credit report from AnnualCreditReport.com. Look for errors—wrong accounts, incorrect balances, or fraudulent accounts. Dispute errors in writing within 30 days per FCRA guidelines. Each error removal can add 10-50 points.

Month 2: Call every creditor you're 30+ days late on. Explain your situation and ask if they'll accept a payment plan. Get any agreement in writing. Making one payment gets you to 29 days late (still reported as late but stopping the damage). Within 30 days, you become current again.

Month 3: Pay down your highest utilization cards first. If you have a card at 95% utilization, pay it down to 30%. This single action could add 50-100 points.

If your score is 580-669 (Fair Credit):

Month 1: Same as above—check for errors.

Month 2: Focus on credit utilization. Your goal is to get all cards under 30%. Calculate how much you need to pay: if you have $5,000 in balances, get to $3,000.

Month 3: Never miss another payment. Set up automatic minimum payments on all accounts to prevent late payments.

If your score is 670+ (Good or Better):

Focus only on payment history and utilization. Don't apply for new credit unnecessarily. Keep accounts open. Continue making on-time payments.

Timeline to expect:

Hard inquiries: 5-10 point drop, recovers in 3-6 months.

Late payment removed from report: 7 years after original delinquency date; score improves 50-150 points when it falls off.

Error dispute: 20-30 days to resolution; can add 10-50 points per error removed.

Utilization reduction: Improvement within 1-2 billing cycles; can add 20-100 points.

Payment history building: Gradual improvement over 6-12 months of on-time payments; add 10-20 points per month in early stages.