If your score shows 720 on Credit Karma and 680 through your bank, you’re not seeing a mistake — you’re seeing two different scoring models look at the same credit file and weigh it differently. FICO and VantageScore are separate companies with separate formulas, and a lender who pulls your FICO 8 score can land 20-40 points away from the VantageScore 3.0 or 4.0 your free app shows you.

Why the gap exists in the first place

Both models pull from the same three bureaus — Equifax, Experian, TransUnion — but they don’t read the file the same way. The three biggest differences:

That last row matters more than people think. If you’ve been paying down a card every month for six months, VantageScore 4.0 can reward you for the trend even before the balance hits zero. FICO 8 — still the model most lenders use for mortgages and auto loans — doesn’t look at direction, only the snapshot.

Which one actually decides whether you get approved

Here’s the part free apps don’t tell you: 90% of lenders still pull a FICO score, not VantageScore, according to FICO’s own disclosures to investors. Mortgage underwriting in particular is locked into FICO by Fannie Mae and Freddie Mac rules. So the number your bank’s app shows you for free is usually VantageScore-based (Credit Karma uses VantageScore 3.0, for example) — useful for tracking trend, not the number that gets you approved for a car loan next month.

This is the same reason a hard inquiry can hit your FICO score by a few points while barely moving VantageScore — the models don’t weight new credit the same way either.

A real example

One reader comparison we tracked: a credit file with one secured credit card at 15 months old, utilization sitting at 9%, no late payments, no collections. VantageScore 3.0 on Credit Karma: 701. FICO 8 pulled by an auto lender two days later: 664. A 37-point gap on the identical credit file, purely from how each model weighted the account age and the thinness of the file (one account only).

The fix for a thin file like that isn’t choosing a model — it’s adding a second account that reports. Becoming an authorized user on a long-standing account is the fastest legal way to thicken a file and close that gap on both models at once, because both reward longer average account age.

What to actually do with this

• Before applying for a mortgage or auto loan: don’t trust the free app number. Ask the lender directly which model and version they pull, or expect your real score to land lower than what Credit Karma shows.
• If you’re tracking progress month to month: pick one model and stick with it. Comparing a VantageScore reading in January to a FICO reading in March will make normal progress look like a drop.
• If the gap is wide (30+ points): it’s usually a thin file or a recent inquiry, not an error. Check which accounts are reporting to each bureau before assuming something’s broken.

Neither score is “the real one.” They’re two different lenses on the same file, and knowing which lens is in front of the person deciding your loan is worth more than chasing a higher number on whichever app happens to be free.