USMLE Step 1 mock exam: all 280 questions
280 questions · 14 blocks of up to 20 · 30 minutes per block
The 2026 USMLE format: 280 single-best-answer questions in 14 timed 30-minute blocks, with each content area’s share of the exam from the USMLE content outline. You get your percentage correct, your score in every content area and a worked review of every question with a note on every option.
Before you start
- Every question is a clinical vignette with five options and one best answer. Step 1 questions ask for the mechanism, cause or finding behind the case. When you submit, every question opens with why the key is best, a note on every option and the reference behind it. A lab values panel is one click away, as on test day.
- As in the 2026 test software, each block has its own 30-minute clock. Inside a block you can skip, go back, change answers and mark questions. Ending a block, or its clock running out, closes it for good; the next block starts when you are ready, so breaks are untimed here. Your sitting is kept in this browser across reloads.
Create a free account before you start
Create a free account to start. Every drill includes one free attempt. A USMLE pass unlocks the full-length Step 1 and Step 2 CK mock exams and unlimited drills in every content area.
Original practice questions written to the USMLE content outlines and current standard references. USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and NBME. Independent practice, not affiliated with or endorsed by the FSMB, NBME or Intealth (ECFMG).
Free USMLE Step 1 sample questions
Five questions in the mock’s format, with the answer, explanation and source after each. No account needed.
A 14-month-old boy is brought to the physician because of pallor, poor feeding and abdominal distension. His parents are first cousins. Examination shows frontal bossing, maxillary prominence and hepatosplenomegaly. Hemoglobin is 5.8 g/dL and mean corpuscular volume is 62 μm³. A blood smear shows target cells, marked anisopoikilocytosis and nucleated erythrocytes. Hemoglobin electrophoresis shows no hemoglobin A and markedly increased hemoglobin F. Which of the following is the main mechanism of his anemia?