"Credit score" and "FICO score" get used interchangeably in everyday conversation, but they're not quite the same thing — the relationship is closer to how "tissue" and "Kleenex" work: one is the general category, the other is a specific branded product within it. * A credit score is the broad category: any numerical output produced by a credit scoring model, based on the information in your credit report from one of the three major bureaus. Multiple companies build these models, and they don't all weigh the underlying factors — payment history, credit utilization, account age — in exactly the same way. * FICO is one specific brand of credit score, developed by the Fair Isaac Corporation, and it happens to be the dominant one: roughly 90% of top lenders use some version of a FICO Score when making lending decisions, which is why it's become the de facto standard people mean when they say "credit score" generically. * The main alternative is VantageScore, a scoring model developed jointly by the three credit bureaus themselves as a competing standard. Because VantageScore and FICO use different underlying formulas, they can produce meaningfully different numbers from the exact same credit report — differences of up to 100 points between the two aren't unusual for the same person on the same day. * This matters practically because the free score you see on a banking app or credit monitoring service is often a VantageScore, while the specific score a mortgage lender pulls to approve your loan is very likely a FICO Score — so the number you've been tracking casually may not match what actually decides your loan approval.