Selection Index Calculator
The Selection Index is the only number National Merit looks at. Enter your two section scores and see it, the national Commended level, and the Semifinalist cutoff for your state.
Both numbers are printed on your PSAT score report. They always end in a zero.
Selection Index
Reading & Writing 720 · Math 700 · total 1420
The formula, and why it is not a percentage
Reading and Writing counts twice, Math counts once. That single detail is the most consequential thing on this page, because it means the shape of your score matters as much as its size.
The index is not a percentage of anything and it is not your total divided by ten. It runs 48 to 228, which happens to line up with the 1520 total at the top and nothing else along the way. Two students with a 1400 total can be five or six index points apart purely because of how the 1400 was split.
How many questions each index level takes
Working backwards through the same conversion curve, here is roughly what each Selection Index target costs in correct answers. The split shown keeps the two sections within a few points of each other, because that is how most real score reports look.
| Selection Index | Questions correct | R&W + Math | Section scores |
|---|---|---|---|
| 208 | 81 of 98 | 44 + 37 | 690 / 700 |
| 210 | 82 of 98 | 45 + 37 | 700 / 700 |
| 215 | 86 of 98 | 48 + 38 | 720 / 710 |
| 220 | 92 of 98 | 50 + 42 | 730 / 740 |
| 223 | 94 of 98 | 51 + 43 | 740 / 750 |
One thing this table hides: a lopsided split reaches the same index with fewer total questions, because every Reading and Writing question is worth roughly twice the index of a Math question. 52 Reading and Writing questions plus 25 in Math gets to 208 with 77 correct answers, against the 81 in the balanced split above. It is real, and it is not advice — planning to be near-perfect on one section is a worse bet than being solid on both.
What moved between the last two classes
Every state cutoff fell for the Class of 2027. New Jersey and the District of Columbia stayed at the top with 223, down from 225; the floor dropped to 208, which is also the national Commended level. That combination — a lower floor and a lower ceiling — is unusual, and it is the reason last year's number is a rough guide rather than a target. The full table is here.