Key Takeaway: The Free 137 is a retired NBME self-assessment with 137 multiple-choice questions that functions best as a diagnostic tool, not a study resource. Take it early, use the score interpretation table below to gauge where you stand, then build your study plan around the gaps it reveals. Just know it covers zero CCS content, which accounts for roughly 25% of your final Step 3 score.
What the Free 137 Actually Is
The "Free 137" is a retired NBME Step 3 self-assessment form containing 137 multiple-choice questions. NBME periodically retires its paid practice exams and releases them at no cost. This particular form became the most widely circulated Step 3 practice resource for a simple reason: it is free and it is written by the same organization that writes the real exam.
The 137 questions span both the Foundations of Independent Practice (FIP) and Advanced Clinical Medicine (ACM) content areas. You will see questions across internal medicine, surgery, pediatrics, OB/GYN, psychiatry, preventive medicine, and biostatistics. The distribution roughly mirrors what you will encounter on the actual exam, though the difficulty level skews slightly easier.
It does not include CCS cases. This matters because CCS is a separate skill that requires dedicated simulation practice, and no amount of MCQ review will prepare you for it. For a comprehensive overview of CCS preparation, see our complete guide to USMLE Step 3 CCS cases. More on the CCS gap below.
How to Access the Free 137
You can find the Free 137 through the NBME website under their self-assessment tools section. Here is what you need to know about access:
- No registration fee. You will need an NBME account, but the form itself is free.
- Available online only. You take it through the NBME's web-based testing interface, which is similar to (but not identical to) the Prometric interface.
- Repeatable. You can retake it, though the questions do not change between attempts. A second pass is useful for reviewing explanations but not for generating a new baseline score.
- Explanations included. After completing the assessment, you get answer explanations for every question. These explanations walk through the reasoning for the correct answer and, in most cases, explain why the distractors are wrong.
The testing interface does not perfectly replicate Prometric, but it is close enough for diagnostic purposes. Do not worry about the interface differences. Focus on the content.
When to Take the Free 137 in Your Study Timeline
The timing of when you take the Free 137 matters more than most people realize. Here is the strategic approach:
Take it at the very start of your dedicated study period. Many test-takers make the mistake of "saving" the Free 137 until they feel ready. This defeats its purpose. The Free 137 is most valuable as a diagnostic tool, not a confidence booster. Taking it early reveals your baseline and tells you exactly where to focus your limited study time.
Ideal timeline placement:
- 6 to 8 weeks before your exam: Take the Free 137 cold (minimal or no Step 3 specific review). This gives you a true baseline.
- 3 to 4 weeks before your exam: If you scored below 65% on your first attempt, consider retaking a different NBME form (paid) to measure progress. Do not retake the Free 137 itself since you will remember questions.
- 1 to 2 weeks before your exam: Take a paid NBME form for your final readiness check. The paid forms provide a three-digit score estimate, which gives better predictive data at this stage.
If you are a busy resident with a compressed timeline (two to four weeks of study), take the Free 137 on day one. Every day counts, and you cannot afford to study blindly.
How to Interpret Your Free 137 Score
The Free 137 does not generate a three-digit score like paid NBME forms. You get a percentage correct. Use this table to roughly gauge where you stand:
| Free 137 Performance | What It Means | Recommended Action |
|---|---|---|
| 80%+ correct | Strong MCQ foundation | Shift focus heavily to CCS practice and weak-area review |
| 75 to 79% correct | Solid position | Targeted MCQ review of weak subjects plus dedicated CCS prep |
| 65 to 74% correct | Adequate baseline | Systematic content review with a question bank plus CCS practice |
| 55 to 64% correct | Knowledge gaps present | Prioritize high-yield content review before heavy CCS practice |
| Below 55% correct | Significant gaps | Consider extending study timeline and focusing on core content first |
A few important caveats on interpreting these numbers:
The Free 137 skews slightly easier than the real exam. Most test-takers report that actual Step 3 MCQs feel harder. If you are scoring 65% on the Free 137, assume your actual MCQ performance will be a few points lower. Build in a margin of safety.
Your score is a snapshot, not a prediction. The Free 137 measures MCQ readiness at one point in time. Your actual Step 3 score also factors in CCS performance, which can move your total score significantly in either direction.
Content area breakdown matters more than the overall percentage. If you scored 75% overall but got 40% of biostatistics questions wrong, that tells you exactly where to invest your study hours. Track your performance by subject.
Using the Free 137 as a Diagnostic Tool
The real value of the Free 137 is not the practice itself. It is the data it generates about your knowledge gaps. Here is how to extract maximum diagnostic value:
Review every question, including correct ones
For questions you got right, ask yourself whether you knew the answer or guessed well. A lucky guess on a cardiology question means cardiology still needs review. Be honest with yourself during this process.
Flag recurring weak areas
Step 3 tests certain topics more heavily than Step 2 CK. Many residents are surprised by how much the exam emphasizes:
- Biostatistics and study design (number needed to treat, sensitivity/specificity, study types)
- Patient safety and quality improvement (root cause analysis, sentinel events, error reporting)
- Screening guidelines and preventive medicine (USPSTF recommendations, age-appropriate screening)
- Ethics and medicolegal questions (informed consent, capacity, advance directives)
If the Free 137 reveals weakness in these areas, prioritize them. They are high-yield and many residents underprepare for them.
Map your results to a study plan
Once you have your content area breakdown, allocate your study time proportionally to your weaknesses. A resident who scores 90% on cardiology and 50% on biostatistics should spend very little time on cardiology and a lot of time on biostatistics. This sounds obvious, but most people default to studying what they already know well because it feels productive.
How the Free 137 Compares to the Real Exam
Understanding the differences between the Free 137 and the actual Step 3 helps you calibrate your expectations:
Question difficulty. The Free 137 questions are generally one step below actual exam difficulty. Step 3 MCQs tend to have longer vignettes, more nuanced answer choices, and more "next best step" questions that require clinical reasoning rather than recall.
Content coverage. With 137 questions, the Free 137 covers a fraction of testable topics. The actual Step 3 has roughly 480 MCQs across multiple blocks. You will encounter topics on test day that the Free 137 never touched.
Testing format. The real Step 3 is computer-adaptive within blocks, meaning question difficulty adjusts based on your performance. The Free 137 is static and cannot replicate the experience of facing increasingly difficult questions as you perform well.
CCS component. The most significant difference. Step 3 includes 13 CCS cases that account for approximately 25% of your score. The Free 137 includes none. Practicing with realistic CCS simulations, like the 175+ cases available on MasterCCS, is the only way to build the pattern recognition and interface fluency that CCS demands.
Specific Tips for Maximizing Your Free 137 Experience
Simulate real testing conditions. Take the full 137 questions in a single sitting with timed blocks. No phone, no reference materials, no breaks beyond what the real exam allows. The diagnostic value drops if you take it casually over several days.
Do not use the Free 137 as your primary question bank. It is a diagnostic tool, not a comprehensive review. After extracting your baseline data, move on to a dedicated Step 3 question bank. Most successful test-takers complete 1,500 to 2,500 practice questions total.
Cross-reference explanations with current guidelines. The Free 137 is a retired form, and some clinical recommendations may reflect older guidelines. Verify treatment answers against current standards, particularly for hypertension management, diabetes screening, and antibiotic stewardship.
Start CCS practice in parallel. Do not wait until you finish your MCQ review to begin CCS practice. CCS builds a different skill set (real-time clinical decision-making, order entry fluency, time management) that improves with repetition over weeks, not days. Starting CCS practice from day one of your study period gives you more time to develop these skills. There are several free CCS practice cases you can use to get started immediately. MasterCCS cases provide detailed feedback on your clinical management, so each case you practice directly improves your performance.
Frequently Asked Questions
Is the Free 137 enough to pass Step 3?
No. The Free 137 is a diagnostic tool, not a comprehensive study resource. It gives you 137 questions out of the thousands of possible topics, and it includes zero CCS practice. Use it to establish your baseline, then supplement with a full question bank and dedicated CCS simulation practice.
How accurate is the Free 137 at predicting my Step 3 score?
It provides a rough estimate of your MCQ readiness, but it cannot predict your total Step 3 score because it does not account for CCS performance. Paid NBME forms give more accurate three-digit score predictions. Treat the Free 137 as directional guidance, not a precise forecast.
Should I retake the Free 137 to measure improvement?
Retaking the same form has limited value because you will remember questions from your first attempt. Your score on a retake will be artificially inflated. If you want to measure progress, take a different NBME form (paid) instead. Reserve the Free 137 retake for reviewing explanations you want to revisit.
When is the best time to take the Free 137 relative to my exam date?
Take it at the beginning of your dedicated study period, ideally six to eight weeks before your exam. This maximizes its value as a diagnostic tool. If you only have two to four weeks, take it on day one. The data it provides is most useful when you still have time to act on it.
Are the Free 137 explanations good enough for learning the material?
The explanations are solid for understanding the reasoning behind individual questions, but they are not a substitute for systematic content review. Use the explanations to understand question logic and identify weak areas, then use textbooks or a question bank for deeper learning on those topics.
What percentage do I need on the Free 137 to feel confident about passing?
Scoring 75% or higher suggests a strong MCQ foundation, but remember that the Free 137 is slightly easier than the real exam. Build in a margin. Also, MCQ readiness is only part of the equation. Even a perfect Free 137 score does not guarantee you are ready for CCS. Prepare for both components independently.
The Bottom Line
The Free 137 is a valuable free resource when used correctly: as a diagnostic tool taken early in your study timeline. Take it under real conditions, use the score interpretation table to gauge your standing, mine the content area breakdown for study priorities, and move on to comprehensive preparation that includes both MCQ practice and CCS simulation.
Your Step 3 score depends on MCQ performance and CCS performance together. The Free 137 addresses one of those. For the other, dedicated simulation practice with a platform like MasterCCS is the most direct path to building the clinical decision-making skills that CCS demands.