The Free 120 is the official set of 120 free sample questions for the United States Medical Licensing Examination (USMLE) Step 2 Clinical Knowledge (CK). You can get it from usmle.org as a PDF booklet and as an online test. Our explanations are original, keyed by item number, and split into three blocks of 40.
Written by Derek Nicolas, medical student. Facts checked against the USMLE Step 2 CK sample questions page, the USMLE Step 2 CK exam page, the USMLE exam resources page, the official Step 2 CK sample questions booklet (updated July 2023) and the NBME self-assessment page on 12 November 2026.
| Question | Answer |
|---|---|
| Official name | USMLE Step 2 CK Sample Test Questions (PDF booklet) |
| Current edition | The booklet on usmle.org says it was updated July 2023 |
| Number of questions | 120, in 3 blocks of 40 (items 1-40, 41-80 and 81-120) |
| Booklet timing | Up to 1 hour per block, 3 hours in total |
| Official answer key | Page 64 of the booklet (answer letters only, no explanations) |
| Cost | Free on usmle.org |
| Our explanations | Original, by item number. The questions are not reproduced. |
Where are the Step 2 CK Free 120 answer explanations for each block?
Each block has its own page. Open the official booklet next to it and follow along by item number.
| Block | Items | Booklet pages | Largest subject groups (our tagging) | Explanations |
|---|---|---|---|---|
| Block 1 | 1-40 | 13-28 | Cardiovascular (4), biostatistics and prevention (4) | Block 1 explanations |
| Block 2 | 41-80 | 29-46 | Obstetrics and gynecology (6) | Block 2 explanations |
| Block 3 | 81-120 | 47-62 | Psychiatry (6); obstetrics and gynecology, endocrine and respiratory (4 each) | Block 3 explanations |
Each block page gives you:
- the answer letter for every item, so you can score yourself;
- why the right answer is right;
- why each of the other options is wrong;
- the learning point (the “educational objective”) of each item;
- a table of the block’s items by subject.
Where do I get the official Free 120?
Both versions are on the USMLE Step 2 CK sample test questions page:
- PDF booklet. The official booklet has the 120 questions, a table of normal lab values, an answer form (page 63) and the answer key (page 64).
- Interactive version. For exams that begin on or after 7 May, USMLE says to use the new Step 2 interactive testing experience. It helps you get used to the new 30-minute blocks. The new software started on 7 May 2026. The booklet says the online items also include questions and formats that are not in the booklet, such as items with audio.
Our item numbers follow the PDF booklet. The July 2023 booklet says most of its questions are the same as those on the USMLE website. We have not checked the new online version item by item, so if you practise online, use the PDF booklet to match the item numbers.
Has the Step 2 CK format changed since the Free 120 was written?
Yes, the block length has changed. Since 7 May 2026, Step 2 CK is one 9-hour session with sixteen 30-minute blocks, and each block has no more than 20 questions. Before that date it had eight 60-minute blocks of up to 40 questions. The booklet still uses the older layout: three blocks of 40 questions, with up to 1 hour per block.
The pace is the same. A full 40-question block in 60 minutes and a full 20-question block in 30 minutes both give you 90 seconds per question.
How should I use the Free 120 explanations?
- Learn the software first. The booklet advises you to run the tutorial and the interactive items on the USMLE website well before your test date.
- Do one block, timed, with no notes. The booklet allows up to 1 hour per 40-item block. Our suggestion: to copy the current exam, do each block as two halves of 20 items, with 30 minutes for each half.
- Score yourself before you read anything. Mark your answers on the answer form (page 63), then check them with the official key (page 64).
- Then open our page for that block. Read the explanation for every item you missed and every item you guessed. Find it by its item number.
- Write down the learning point of each miss and its subject. A subject with several misses is where to spend your next study hours.
- Repeat with the other two blocks. Our view: leave enough days after the Free 120 to work on the weak subjects it shows.
What can the Free 120 tell me about my Step 2 CK score?
It cannot give you a three-digit score. Neither the booklet nor the USMLE sample questions page gives a way to turn your Free 120 percentage into a Step 2 CK score. We do not offer one either.
The booklet itself gives two warnings. The sample questions show the kind of content on the exam, but they may not match the content mix of your own exam. And most examinees feel more time pressure on test day than in practice.
In our view, the Free 120 is useful to check three things:
- whether you can keep a steady pace for a full block;
- whether you are comfortable with each question format the booklet shows: single questions, sequential item sets (two or three questions about one patient) and research abstracts;
- which subjects cost you the most marks.
If you want a score estimate, NBME sells the Comprehensive Clinical Science Self-Assessment. NBME says it reports your estimated probability of passing Step 2 CK and includes a lookup table for USMLE scores. NBME also says the estimate is not a guarantee.
Once you have a score, our guide explains Step 2 CK percentiles.
Why don’t you show the Free 120 questions?
The questions belong to the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME), and the booklet says all rights are reserved. So we explain each item by its number only. Keep the official booklet open next to our pages.
Do your item numbers match my Free 120 booklet?
Yes, if your booklet is the edition updated July 2023. That was the edition on usmle.org on 12 November 2026. On that day we checked our three block pages against it: all 120 item numbers, booklet page numbers and answer letters match. The edition date is on the page after the cover. If your copy shows a different date, the numbers may not match.
Spotted an error? Tell us through our contact page and we will correct it.
Our revision notes: If you want one condensed resource for revision, our USMLE Step 2 CK High-Yield Notes are a paid, typed PDF written by the Recall Mastery team, organised by topic, with tables, charts and diagrams. Use them alongside question practice, not instead of it.
Related guides
- Step 2 CK study schedule: 8-week plan with 4-, 6- and 12-week versions
- NBME CCSE exam: format, scoring and a study plan
- USMLE passing scores for Step 1, Step 2 CK and Step 3
Recall Mastery is not affiliated with USMLE, NBME, FSMB or ECFMG.