Your credit score is a three-digit number calculated by a handful of private companies using a formula you do not control, reported to lenders who then use it to decide whether to rent you a house, give you a car loan, or charge you an extra two percent on a mortgage. It feels mysterious. It is not. There are five factors, they are publicly disclosed, and once you understand them you can move your score deliberately instead of hoping.

The most common score lenders use is the FICO score. VantageScore is similar but weighted slightly differently; what you see on Credit Karma is a VantageScore, which is why it sometimes disagrees with the number your mortgage lender pulls. For this article we will stick with FICO because it is what actually gets used when you apply for credit.

The five factors, in order of weight

FICO says its formula breaks down roughly like this:

  • Payment history: 35%
  • Amounts owed (credit utilization): 30%
  • Length of credit history: 15%
  • Credit mix: 10%
  • New credit: 10%

If you already pay your bills on time, the 35% line is doing its job and you have nothing to fix. That means the only serious lever left is utilization, which is why most of the real movement in credit scores comes from changing that one number.

Payment history (35%): the most important thing

Pay every bill at least the minimum by the due date. Full stop. Late payments, especially those that hit 30+ days past due, have an outsized negative impact that can take years to fade.

The single best thing you can do here is set up autopay on every credit account for at least the minimum payment. You can still pay the full balance manually if you prefer to manage cash flow, but the autopay on the minimum is a safety net against the month you forget. One 30-day-late payment can drop a 780 score into the 700s for 12 to 24 months.

Autopay the minimum on every card, every loan, every utility that reports. You can always pay more by hand. You cannot retroactively unforget a due date.

If you already have a late payment on your report, it will age out of reporting after seven years. In the meantime, a goodwill letter to the creditor asking them to remove it can occasionally work, especially if you have a long clean history otherwise. Not guaranteed, but free to try.

Utilization (30%): the biggest lever if you already pay on time

Utilization is how much of your available credit you are using. The formula is simple:

Utilization = (total balances) / (total credit limits)

Example:
  Card A: $2,400 balance on $5,000 limit
  Card B:   $600 balance on $3,000 limit
  Card C:   $0 balance on $10,000 limit
  ---------------------------------------
  Total balance: $3,000
  Total limit: $18,000
  Utilization: 16.7%

Lower is better. The conventional wisdom is to stay under 30%. The actual research suggests the best scores come from utilization in the 1% to 9% range. Zero utilization across the board is slightly worse than a small utilization, because zero signals no activity.

Here is the important, non-obvious part: utilization is measured on the statement date, not the payment due date. So if your card closes on the 20th and you pay on the 15th of the next month, whatever balance is on the card on the 20th is what gets reported. If you use your card heavily, pay it off in full every month, and never carry a balance, your utilization can still report at 40% because the statement captured it mid-cycle.

The fix is to either pay down the card before the statement date, or to make a mid-cycle payment. Check your online portal for the statement close date, set a calendar reminder two days before, and pay down to under 10% of the limit before that date. Your next reported utilization will drop and your score will move within one to two cycles.

Individual-card utilization also matters, not just the total. A single card at 85% utilization hurts even if your total is 10%. If you have one card close to its limit, prioritize paying that one down first.

Length of history (15%): time is the cheat code

This factor rewards average age of accounts and the age of your oldest account. There is very little you can do to speed it up other than not opening a lot of new accounts (which lowers your average age) and not closing old accounts (which can eventually remove them from the calculation).

The one actionable move: if you have an old credit card you do not use but still have open, keep it open. Even better, set a small recurring charge on it (a $9.99 streaming subscription works) and autopay the full balance. This keeps the account active, contributing to your average age and your total available credit.

Credit mix (10%): exists, but do not chase it

FICO rewards having a mix of installment loans (auto loans, mortgages, student loans) and revolving credit (credit cards). You should not take on a loan you do not need just to diversify your credit mix. The points on offer are small.

If you have only one type of credit (say, only a car loan, or only credit cards) and you are trying to buy a house, the mix piece will eventually sort itself out when the mortgage closes. Until then, focus on the bigger levers.

New credit (10%): hard inquiries and new accounts

When you apply for credit, the lender pulls a hard inquiry, which shows on your report for 24 months and factors into your score for 12 months. A single inquiry typically costs 2 to 5 points. Several in a short period (outside of rate-shopping for a mortgage or auto loan, which are bundled) can cost more.

Opening a new account also lowers your average age of accounts, which affects the 15% length factor. So a new credit card application hits you on both fronts briefly.

The practical implication: do not apply for new credit in the 6 to 12 months before a major loan application (mortgage, auto loan, refinance). Outside of that window, responsibly adding new cards to your profile is fine, and over time it raises your total credit limit (improving utilization) and your credit mix.

The myths worth clearing up

Three myths we still hear constantly:

“Carrying a balance helps your score.” No. Paying the full statement balance every month is the correct move. Carrying a balance costs you interest and does not help your score. This myth probably comes from the idea that some activity is better than no activity, which is true; but you can have activity without paying interest, just by using the card and paying it off in full.

“Closing old cards will help.” The opposite. Closing a card lowers your total credit limit (raising utilization) and eventually reduces your average age of accounts. Unless the card has an annual fee you do not want to pay and cannot product-change out of, keep it open.

“Checking your own credit hurts your score.” No. Checking your own credit is a “soft pull” and has no impact. Do it as often as you like. Hard inquiries are when a lender pulls it to make a lending decision, and those are the ones that count.

Where to actually check your score for free

You have more free options than you think:

  • annualcreditreport.com: the official, free, federally mandated site for your actual credit reports from Experian, Equifax, and TransUnion. Pulls the reports, not the scores. Weekly access is free now.
  • Credit Karma: free VantageScore, updated weekly. Not the FICO, but directionally useful.
  • Experian's free account: free FICO 8 score. This one matches what a lender is most likely to see.
  • Your bank or credit card: Chase Credit Journey, Capital One CreditWise, Discover's FICO tool, Amex MyCredit Guide. All free, most update monthly or weekly.

Pick one and check monthly. You do not need three. The goal is to notice unusual changes, not to watch the number move day to day.

What score you actually need

Scores run from 300 to 850. Rough 2026 thresholds for common decisions:

  • Apartment rental: 620+ works in most markets. 660+ removes most friction.
  • Auto loan at non-garbage rates: 680+ for reasonable rates, 720+ for the best advertised rates.
  • Mortgage (conventional): 620 is the technical minimum, 740+ is where you stop paying a credit-score surcharge. The difference between 680 and 760 on a $400,000 mortgage is roughly $60,000 in interest over 30 years.
  • Premium rewards credit cards: 720+ for most approvals on Chase Sapphire Reserve, Amex Platinum, Capital One Venture X.

Above 760, the marginal improvement stops mattering for most decisions. An 820 gets you the same rate as a 780. Do not optimize past that point; you are wasting effort.

What we'd actually do

In the next ten minutes: set up autopay on minimum payments for every credit account you have. That locks in the 35% factor forever and is the single biggest move most people have not made.

This week: check your current utilization on each card. If any card is above 30%, pay it down before the next statement closes. If your total utilization is above 10%, figure out whether to pay down balances or ask for credit limit increases (most issuers will grant one every six to twelve months with a soft pull).

Then stop touching it. Credit scores reward patient, consistent behavior. Do the two big things, keep your oldest account open, avoid new credit in the year before a big loan, and the number will climb on its own.