Credit Scores & How They Work
A credit score is a lender's three-digit shortcut for predicting whether you'll pay back a loan. The math is mostly public — and the levers are smaller than people think.
What a score actually is
Two main systems are used in the US: FICO (most lenders) and VantageScore. Both run roughly 300–850 and crunch the same five buckets of behavior on your credit reports from Equifax, Experian and TransUnion.
It's NOT a measure of wealth, income, or how "responsible" you are in general. It only tracks credit behavior.
Why it matters
The score is the biggest factor in: mortgage and auto-loan interest rates, credit-card approval, apartment rentals, sometimes job offers and insurance pricing.
The gap between 620 and 760 on a $300k mortgage can be over $100,000 in lifetime interest. Single highest-leverage 3-digit number most people have.
The five factors (FICO)
Score bands (FICO)
% column ≈ share of US consumers in each band per FICO's distribution data.
Score simulator
Top moves for this profile
Myth vs Fact
MYTHClosing an old card boosts your score
It usually drops it — shortens average account age and shrinks total credit limit (raising utilization).
FACTChecking your own credit doesn't hurt your score
That's a soft inquiry. Only hard pulls from new applications count.
MYTHCarrying a balance improves your score
False. Pay in full each month. The card reports your statement balance to bureaus regardless.
FACTYou can pull a free report once a year per bureau
AnnualCreditReport.com is the official, free source. (Many issuers also offer free FICO views.)
MYTHIncome is part of your credit score
No. Income is not on credit reports and doesn't factor into the score. Lenders ask for it separately.
FACTMultiple mortgage/auto inquiries in 14–45 days count as one
Both FICO and VantageScore allow rate-shopping windows to avoid penalizing comparison shopping.
MYTHPaying off collections instantly removes them
Older FICO models still count paid collections. Newer ones (FICO 9, 10, VantageScore 4) ignore paid medical or small ones.
FACTAuthorized-user status can lift a thin file
Being added to a long-standing, low-utilization card can boost an early-builder's history overnight.
Connect the dots
Quiz
15 questions on credit-score mechanics.
Flashcards
Tap to flip. Key credit-score terms.
Teacher mode
Lesson outline, quick reference, and a printable worksheet with answer key.
Lesson outline (40 min)
- 5 min · Hook — Show the band table. Ask: "What's the most expensive 3-digit number in your life going to be?"
- 10 min · The five factors — Walk through the FICO weights. Emphasize 35% + 30% = 65% from payment history and utilization alone.
- 10 min · Simulator — Demo how each lever moves the gauge. Have students predict, then check.
- 10 min · Myth-bust — Cover the 8 myth/fact tiles. Most students walk in believing at least three of the myths.
- 5 min · Wrap — Identify the single highest-leverage action for each student (most common: pay in full + lower utilization).