Difference of scores between mgmat,gmatprep and the gmat.

It's very difficult to compare scores among the different test prep makers. Each company has their own algorithm for calculating scores, which is different from what you'll find on the real GMAT.

What I would do is to compare your scores from a single company and make sure that you're directionally improving. For example, if you had taken 3 MGMAT tests and 3 Kaplan tests, don't compare your scores holistically. Rather, compare your MGMAT scores to one another and Kaplan scores to one another to see whether you're on the right track with your studies.

Also note that GMAT Prep is going to be the most accurate practice test that you can take. These tests feature real but retired GMAT questions. From what I've seen, GMAT Prep is an excellent indicator of what you'll actually get on the real test.

Good luck!

You're welcome, SB. But the community deserves the real credit here--our members are awesome!