# sat-score-projection
Estimate a **digital SAT** total scaled score (400–1600) from the number of raw
correct answers in the Reading & Writing and Math sections. Pure, dependency-free
Rust math — the same engine behind the [ExamScoreCalc](https://examscorecalc.com/)
score projector.
## Important: this is an estimate, not a prediction
The digital SAT is **section-adaptive**: the difficulty (and scoring weight) of
each section's second module depends on first-module performance. The College
Board **does not publish** exact raw-to-scaled conversion tables, so there is no
single deterministic mapping from "questions correct" to a scaled score — the same
raw count can yield different scaled scores depending on module routing.
This crate uses a deliberately **transparent linear model** that approximates the
published score scale (each section 200–800; total 400–1600) across the full raw
range. It is meant for orientation and "what-if" planning, **not** as a prediction
of any individual's official score. Treat every output as ± a few tens of points.
## Usage
```rust
use sat_score_projection::{section_score, digital_sat_total};
let rw = section_score(40, 54); // ~40 of 54 Reading & Writing correct
let math = section_score(30, 44); // ~30 of 44 Math correct
let total = digital_sat_total(40, 30); // total 400–1600 estimate
assert!((200.0..=800.0).contains(&rw));
assert!((400.0..=1600.0).contains(&total));
```
## Live calculator
For an interactive version with the standard digital-SAT item counts built in,
see the [SAT score projector](https://examscorecalc.com/) at ExamScoreCalc.
If you need a published conversion rather than this approximation, the released
digital-SAT practice forms each ship their own raw-to-scaled table. ExamScoreCalc
runs the table belonging to the form you sat, prints every row of it on the page
rather than hiding the lookup, and returns the score *range* College Board
publishes instead of picking one number inside it — see the
[ExamScoreCalc on crate doc digital sat](https://examscorecalc.com/digital-sat-score-calculator/).
License: MIT