Your credit score isn't one number
TL;DR
- There are 40+ different credit scores. The one Credit Karma shows you is almost never the one a lender sees.
- FICO scores dominate underwriting (90%+ of US lending). VantageScore dominates consumer-facing "free score" products.
- Which flavor of FICO or VantageScore matters — a mortgage pulls different numbers than a credit card application.
The map
Most people think "my credit score" is a single number. It isn't. Every time a lender makes a decision, it pulls a specific scoring model from a specific bureau. Change the model, change the bureau, or change the product — you get a different number.
Credit Karma's 704 is a VantageScore 3.0 from TransUnion. Your mortgage broker's 742 is a FICO 5 from Equifax. Your Chase app might pull a FICO 8 from Experian and show 718. All three are real. None of them is "your credit score."
What to read next
The rest of this hub walks through the landscape:
- FICO vs VantageScore — the two score families, how they differ, why consumer apps tend to show VantageScore even though lenders use FICO. See FICO vs VantageScore.
- FICO model versions — FICO 8, 9, 10, 10T, plus the industry-specific flavors (Bankcard, Auto, Mortgage). See FICO model versions.
- VantageScore versions — 3.0, 4.0, 4plus. Where each shows up. See VantageScore versions.
- Who uses which score — the matrix. Chase pulls X, Amex pulls Y, Ally Auto pulls Z. See Who uses which score.
- The three bureaus — TransUnion, Equifax, Experian. Which issuer prefers which. See The three bureaus.
- Credit factors — payment history (35%), utilization (30%), length (15%), new credit (10%), mix (10%). And how each CardLeverage module moves them. See The 5 credit factors.
Core strategies, after you've got the basics
- Utilization deep dive — overall vs per-card, statement-close timing, AZEO. See Utilization deep dive.
- Authorized user effects — when an AU tradeline helps vs hurts. See Authorized user effects.
- Hard vs soft inquiries — rate-shopping windows, sensitivity by model. See Hard vs soft inquiries.
- Score simulation — roughly how many points each action is worth. See Score simulation — how much does each move matter?.
- Business credit vs personal — why Chase/Amex business cards don't report to your personal report, and why Capital One's do. See Business credit vs personal.
Issuer rules that break the normal model
- Chase 5/24 — the single most important Chase underwriting rule. See Chase 5/24 — the deep dive.
- Amex rules — 2/90, 1/5, 1/8, NLL. See Amex rules — 2/90, 1/5, 1/8, NLL, PUJ.
- Bureau alerts and freezes — when to freeze, how to thaw. See Bureau alerts, freezes, and locks.
Why this matters
If you're going to play the card game seriously — churning sign-up bonuses, maximizing points, optimizing utilization before a mortgage — you have to know which score a given lender is actually reading, or you'll optimize for the wrong number.
Credit Karma shows a fast-moving VantageScore. Your mortgage lender uses a 20-year-old FICO model that weights things differently. Move your VantageScore 40 points and your mortgage FICO might not budge at all.
This hub gives you the mental model, then the specifics.
The headline comparison. Two score families, same 300–850 range today, very different weightings and adoption.
The matrix. Lender by lender, product by product, which bureau and which scoring model actually underwrites the decision.
Payment history 35%, utilization 30%, length 15%, new credit 10%, mix 10%. What each means, how to move it, and which CardLeverage module controls it.