Your credit score is a three-digit number that lenders use to decide whether to lend you money and at what interest rate. A high score saves you thousands of dollars over your lifetime. A low score costs you thousands — or shuts you out of borrowing entirely.
Most people know their credit score matters but have no idea how it’s actually calculated. Once you understand the formula, improving it becomes straightforward.
What Is a Credit Score?
A credit score is a numerical summary of your credit history — how reliably you’ve borrowed and repaid money in the past. Lenders use it to predict how likely you are to repay future debt.
The most widely used scoring model is the FICO score, which ranges from 300 to 850. Higher is better.
| Score Range | Rating | What It Means |
|---|---|---|
| 800–850 | Exceptional | Best rates available, easy approvals |
| 740–799 | Very Good | Near-best rates, strong approval odds |
| 670–739 | Good | Approved for most loans at decent rates |
| 580–669 | Fair | Higher rates, some rejections |
| 300–579 | Poor | Very high rates, frequent rejections |
A score above 740 is where the best interest rates kick in. The difference between a 620 and a 760 score on a 30-year mortgage can easily exceed $50,000 in total interest paid.
How Is a Credit Score Calculated?
FICO scores are calculated from five factors, each weighted differently:
1. Payment History — 35%
The single biggest factor. Do you pay your bills on time? Even one missed payment can drop your score significantly. A payment 30 days late stays on your credit report for 7 years.
This is the most important habit: pay every bill on time, every time. Set up automatic minimum payments as a safety net so you never accidentally miss a due date.
2. Credit Utilization — 30%
How much of your available credit are you using? If your credit card limit is $10,000 and your balance is $3,000, your utilization is 30%.
Lower utilization signals financial discipline. The general guideline is to stay below 30% — ideally below 10% for the best scores. Paying down balances or requesting a credit limit increase both lower your utilization ratio. For a deep dive into the math and why the standard advice might be costing you points, check out our guide on the credit utilization ratio.
3. Length of Credit History — 15%
How long have your accounts been open? Older accounts help your score. This is why closing old credit cards — even ones you don’t use — can hurt your score. The age of your oldest account, newest account, and average age of all accounts all factor in.
4. Credit Mix — 10%
Having a variety of credit types helps your score — credit cards, installment loans (car, mortgage, student), and retail accounts. You don’t need to take on debt just to diversify, but having only one type of credit is slightly less favorable.
5. New Credit Inquiries — 10%
Every time you apply for new credit, a “hard inquiry” appears on your report and temporarily lowers your score by a few points. Multiple applications in a short period signal financial stress to lenders. Rate shopping for a single loan (mortgage, car) within a 14–45 day window typically counts as one inquiry.
What Doesn’t Affect Your Credit Score
Common misconceptions:
- Your income — not a factor in your score at all
- Your savings or investments — not included
- Checking your own score — soft inquiries don’t affect your score
- Debit card usage — debit has nothing to do with credit
- Age, race, gender, nationality — legally cannot be factors
How to Check Your Credit Score
In the US, you’re entitled to one free credit report per year from each of the three major bureaus (Experian, Equifax, TransUnion) at annualcreditreport.com. Many credit cards and banks now show your score for free in their apps.
Check your report annually for errors — incorrect late payments, accounts you didn’t open, or wrong balances. Errors are more common than most people realize and can be disputed and corrected.
How to Improve Your Credit Score
If your score is below 670:
The fastest improvements come from payment history and utilization — the two biggest factors.
- Set up autopay for every account to eliminate missed payments
- Pay down credit card balances as aggressively as possible
- Don’t close old accounts even if unused
- Avoid applying for new credit while rebuilding
If your score is 670–740:
You’re in good territory but optimizing further saves money on future borrowing.
- Get utilization below 10% on each card
- Dispute any errors on your report
- If you have only one type of credit, a small installment loan can help mix
If your score is above 740:
You’re already getting the best rates. Maintain what you’re doing — on-time payments and low utilization. Don’t take on unnecessary debt to chase a perfect 850.
Why Your Credit Score Matters Beyond Borrowing
Most people think credit scores only matter when taking out loans. In reality they affect:
Rental applications — landlords routinely check credit scores. A low score can prevent you from renting the apartment you want.
Insurance premiums — in many places, insurance companies use credit-based insurance scores to set premiums. Better credit can mean lower car and home insurance costs.
Employment — some employers check credit reports for roles involving financial responsibility.
Security deposits — utility companies and landlords may require larger deposits from people with lower scores.
Understanding this context makes it clear why building good credit early — even before you need to borrow — is worth the effort. Once you have a solid credit foundation, you can start thinking about how to put it to work, like understanding the difference between good debt and bad debt and when borrowing actually makes financial sense.
The Bottom Line
Your credit score is a reflection of one thing: how reliably you manage borrowed money. Pay on time, keep balances low, don’t apply for credit you don’t need, and keep old accounts open. Do those four things consistently and your score will take care of itself.
The best time to build good credit habits is before you need them. A strong score is a financial asset that saves you real money every time you borrow.
Read next:
- Good Debt vs Bad Debt — What’s the Difference? — now that you understand credit scores, learn which types of borrowing actually make sense
- What Is Personal Finance and Why Does It Matter? — how credit fits into your overall financial picture