Check Your USMLE Step 1 Pass Probability

How the Step 1 Pass Probability Predictor Works

Since USMLE Step 1 became Pass/Fail on January 26, 2022, preparation is no longer about chasing a 3-digit score — there isn't one anymore. The only question that matters is whether you hold a comfortable statistical margin above the passing standard. This tool answers exactly that: it converts your practice performance into a probability of passing, not a speculative score.

The NBME pass-probability anchor (July 2024)

The estimate is anchored on the NBME's officially published CBSSA pass-probability tablefrom its July 2024 Score Interpretation Guidance. That table is built on the entire Step 1 examinee population — over 100,000 test-takers a year — using the same Item Response Theory framework the NBME uses to set the passing standard. Anchoring on that source data, rather than a self-reported spreadsheet, is why the estimate holds up.

Which NBME forms are most predictive: Forms 29–33

Weight your most recent self-assessments. Forms 29–33 are calibrated to the current Step 1 content and difficulty, so they mirror the live exam most closely, and Forms 32 and 33 are the newest and strongest single predictors. Older forms (25–28) run on harsher, less representative curves and tend to under-predict — use them as early baselines, not as your readiness signal.

Free 120 and UWorld as corroborating signals

The official Free 120, taken within a week of your exam, is the best preview of interface, stamina, and question style — treat it as a confidence check rather than a precise score. A high UWorld first-pass average (roughly 60%+) corroborates readiness but, as a learning tool rather than an assessment, it is a weaker standalone signal. The model weights both below your NBME forms.

Why recency and consistency beat one high score

A single form carries real measurement noise. Two consecutive recent forms showing a comfortable margin is a far stronger signal than one lucky spike, and a flat-or-rising trend matters more than any individual number. The predictor weights recent results more heavily, so an early low baseline does not unfairly drag down a genuinely improved current position.

What NBME Score Means You're Ready for Step 1?

No practice score guarantees a pass, but the NBME's data maps performance to a probability of passing. As a rough guide on recent forms (29–33):

• ~68%+ equated percent correct: a comfortable margin — around a 95%+ probability of passing.
• ~65–67%: likely to pass; take one more recent form to confirm the trend.
• ~60–64%: borderline — a thin margin; shore up your weakest systems before testing.
• Below ~60%: elevated fail risk; consider delaying and rebuilding your foundation.

Enter your exact form and score above for a personalized probability rather than relying on these bands.

Common Step 1 Readiness Scenarios

Strong and consistent

Two recent forms in the high-60s or above, trending flat or up — you have margin. The main risk left is test-day execution, not knowledge. Lock in your timing with the Free 120 and sit the exam.

Borderline or one low form

A single low form among otherwise-solid scores is usually content-specific. Do a blind review to separate content gaps from process errors, spend a focused block on your weakest systems, then re-test on a newer form (32 or 33) before committing to a date.

Rising from a low baseline

An early Form 25 in the 50s followed by a recent Form 32 in the mid-60s is an upward trajectory, and the predictor reads it that way — the recent form dominates. Keep building margin instead of anchoring on the old low.

International medical graduates (IMGs)

The NBME calibration is population-wide, so the pass-probability relationship holds regardless of your school. The practical advice is identical: weight recent forms, build a margin above the line, and confirm stamina on the Free 120.

How Accurate Is This Prediction?

A probability is a population statistic, not a promise about you specifically. A 95% probability of passing means most students with your exact profile pass — not every one of them. Treat the number as a margin of safety, and combine it with official NBME self-assessments rather than reading it as a guarantee. For the full calibration and validation detail, see our Step 1 accuracy insights and our prediction methodology.