A raw PSAT score is calculated the same way as a raw SAT score. For each section (verbal, math, or writing skills), you get one point for a correct answer, but you lose ¹ /₄ of a point for an incorrect regular multiple-choice answer. In the math section, you lose ¹/₃ of a point for each incorrect quantitative comparison answer; there is no penalty for incorrectly answering a grid-in. There is also no penalty for skipped questions.

The first difference between the scoring of the tests comes in the scaled score. On the PSAT, scaled scores range from 20 to 80 (not 200 to 800, as on the SAT). Luckily, verbal and math PSAT scaled scores directly correspond to SAT scaled scores. For example, a combined math and verbal PSAT score of 110 means the same thing as a 1100 on the SAT. To use your PSAT as a gauge of what you might score on the SAT, just take your math and verbal scores, add them together, and multiply them by ten.

For each of your scaled scores, you will also receive a percentile that tells you where your score stands in comparison to the national average. This score can be important, since it is probably the first time that you’ve been ranked against most other students nationwide in your age group.

The inclusion of a selection index score is the most important difference between the score report you will receive for the PSAT and the one you will receive for the SAT. The selection index is just a fancy name for the sum of your verbal, math, and writing skills scaled scores. This score can range from 60 to 240. The selection index is the number that the National Merit Scholarship Corporation uses to select scholarship recipients.