Different scoring models. You cannot use a score generated by one model to determine a score generated by a different model. Different models evaluate report data differently and can even have different score ranges.
You should't expect to "trust" just one score. There are many scoring models used by creditors. Most use one of FICO models (aee also the Understanding FICO Scoring subforum and its stickies) but there are some that use VantageScores. Make sure you're always considiering the specific scoring model when referencing scores. Also make sure you consider the relevance of a given model/CRA combo to a given/creditor product. If, for example, a creditor/product uses a TU FICO 8 in the decision then only that score will matter. Scores generated by other models and based on other CRA data will not be relevant.
For observing overall trends with your credit you can use just about any model you want. FICO 8 is popular since it is the most commonly used model but, again, it is not used for all creditors/products. If you're going to rely on scores you really need to watch trends versus specific numbers. I seriously recommend learning to assess your own reports and focusing on the data in your reports versus obsessing over numbers. You won't be able to determine what your score would be for different models but good reports will lead to good scores and if you want to improve your credit then you'll need such an understanding anyway.
Additionally, CK provides two scores -- a TU VantageScore 3.0 and an EQ VantageScore 3.0. myFICO provides FICO 8's for all 3 major CRA's and limited access to addition FICO models.
This is a very common topic so don't overlook prior discussions as a reources. IIRC the stickies also cover this and can also be a very useful resource.
