# Step 2 CK percentile calculator

> Type a Step 2 CK or Step 3 score and see its percentile on the USMLE norm table updated August 17, 2026, plus the retest band and whether two scores differ.

Markdown copy of https://meduniexam.com/tools/step-2-ck-percentile-calculator (the HTML page), published by MedUni Exam. Published November 5, 2026. Site guide for agents: https://meduniexam.com/llms.txt.

Type a Step 2 CK or Step 3 score to see where it sits on the USMLE's own norm table, updated August 17, 2026: the percent of first takers from LCME-accredited medical schools who scored lower. A 250 on Step 2 CK is the 44th percentile and a 260 the 71st. The calculator also shows the range a retest would likely land in, and whether two scores are far enough apart to mean a real difference. It runs in your browser.

## How the percentile is read

The USMLE defines a percentile rank as the percentage of first takers in its comparison group "who scored lower than a given USMLE Step Examination score". Its own example: "An examinee with a Step 2 CK score of 240 is at the 23rd percentile."

The comparison group is first takers from LCME-accredited medical schools: 67,824 who tested between July 1, 2023 and June 30, 2026 for Step 2 CK, and 64,576 who tested between January 1, 2023 and December 31, 2025 for Step 3. Every score is read against that group.

The table prints a row every 5 points, from 300 down to 160, and a last row for 155 and below. A score on a row is read straight off it. For a score between two rows, the calculator draws a straight line from one row to the next: 247 is two fifths of the way from 245, the 32nd percentile, to 250, the 44th, so it reads as about the 37th. The USMLE publishes only the rows, so that estimate is the calculator's, not the USMLE's, and every answer between two rows says so. Where both rows print the same value, as 0 from 155 up to 205 and 100 from 280 up on Step 2 CK, the answer gives that value and names the two rows.

A printed 0 means that fewer than 1 percent of the group scored lower, and a printed 100 means that more than 99 percent did. The table is one edition. In the guidelines' words, "Norm tables are updated annually by dropping earlier groups of examinees and adding newer ones", so the calculator names the edition it reads: the one updated August 17, 2026.

Step 1 has no percentile here. It is reported as pass or fail only for exams on or after January 26, 2022, so there is no Step 1 score to place.

## Worked examples

- A score of 250 on Step 2 CK sits on a printed row: the 44th percentile. Its retest band runs from 242, about the 27th percentile, to 258, about the 66th percentile.
- A score of 247 on Step 2 CK falls between 245, the 32nd percentile, and 250, the 44th. The straight line between those rows puts it at about the 37th.
- A score of 220 on Step 3 is the 31st percentile, and the Step 3 minimum passing score, 200, is the 4th percentile row.
- Two Step 2 CK scores of 250 and 262 are 12 points apart, under the 16 points of two standard errors of difference, so by the USMLE's rule they are not far enough apart to show a real difference in proficiency.
- The 50th percentile on Step 2 CK falls between 250 (the 44th) and 255 (the 58th). The straight line between those rows puts it at about 252.

The calculator's own code writes these lines, so they match what the form gives for the same numbers.

## The USMLE norm table

Table 2 of the guidelines, every row, as the calculator reads it: the percent of first takers from LCME-accredited medical schools who scored lower than each score, between July 1, 2023 and June 30, 2026 for Step 2 CK and between January 1, 2023 and December 31, 2025 for Step 3.

| Score | Step 2 CK percentile (N = 67,824) | Step 3 percentile (N = 64,576) |
| --- | --- | --- |
| 300 | 100 | 100 |
| 295 | 100 | 100 |
| 290 | 100 | 100 |
| 285 | 100 | 100 |
| 280 | 100 | 100 |
| 275 | 98 | 100 |
| 270 | 93 | 100 |
| 265 | 83 | 100 |
| 260 | 71 | 99 |
| 255 | 58 | 97 |
| 250 | 44 | 93 |
| 245 | 32 | 88 |
| 240 | 23 | 80 |
| 235 | 15 | 69 |
| 230 | 9 | 56 |
| 225 | 6 | 43 |
| 220 | 3 | 31 |
| 215 | 2 | 20 |
| 210 | 1 | 12 |
| 205 | 0 | 7 |
| 200 | 0 | 4 |
| 195 | 0 | 2 |
| 190 | 0 | 1 |
| 185 | 0 | 0 |
| 180 | 0 | 0 |
| 175 | 0 | 0 |
| 170 | 0 | 0 |
| 165 | 0 | 0 |
| 160 | 0 | 0 |
| 155 and below | 0 | 0 |

In 2023 and 2024 the LCME-accredited group included U.S. and Canadian medical schools. From the 2025 calendar year for Step 3 and the 2025-2026 academic year for Step 2 CK, Canadian medical schools were removed from the group.

Source: USMLE Score Interpretation Guidelines, Table 2, updated August 17, 2026, read November 4, 2026.

Table 1 of the same guidelines gives the mean and the standard deviation of the same group by year. The calculator compares a score with the latest year.

| Step | Year | Mean | Standard deviation |
| --- | --- | --- | --- |
| Step 2 CK | 2023-2024 academic year | 249 | 15 |
| Step 2 CK | 2024-2025 academic year | 250 | 15 |
| Step 2 CK | 2025-2026 academic year | 251 | 15 |
| Step 3 | 2023 calendar year | 227 | 15 |
| Step 3 | 2024 calendar year | 227 | 15 |
| Step 3 | 2025 calendar year | 227 | 15 |

Source: USMLE Score Interpretation Guidelines, Table 1, updated August 17, 2026, read November 4, 2026.

## How precise a score is

The guidelines give three measures of how much a score could move, each of them approximate.

- The standard error of measurement is about 6 points on Step 2 CK and 5 on Step 3. It is the general index of how imprecise a score is.
- The standard error of difference is about 8 points on Step 2 CK and 7 on Step 3. In the guidelines' words, "If the scores received by two examinees differ by two or more SEDs, it is likely that the examinees are different in their proficiency." That is the check the calculator runs on a second score: 16 points apart on Step 2 CK and 14 on Step 3. It is the USMLE's rule for two reported scores, not for practice tests.
- The standard error of the estimate is about 8 points on Step 2 CK and 7 on Step 3: "If an examinee tested repeatedly on a different set of items covering the same content, without learning or forgetting, their score would fall within one SEE of their current score two thirds of the time." That is the retest band the calculator prints, one standard error of the estimate either side of the score: the range a retest would land in about two times in three, with no learning or forgetting.

The guidelines add a caution for anyone who compares applicants: "Small differences in Step examination scores alone should not be used as the basis for selection decisions about examinees".

## What this calculator does not do

- It is not a USMLE, NBME or FSMB tool, and this site is not affiliated with any of them.
- It reads every score against first takers from LCME-accredited schools, as the USMLE's own table does, so a repeat taker or a graduate of a school outside that group is read against that group too.
- It reads one edition of the table. The USMLE replaces the table every year, and a percentile read off an older edition can differ by several points.
- It does not compare Step 2 CK with Step 3. The guidelines say that "scores on the two Steps are not directly comparable. For example, a score of 220 on Step 2 CK is not equivalent to a score of 220 on Step 3."
- It does not turn a practice test score into a Step 2 CK score, and it does not estimate residency chances.
- Its estimate between two rows is not a published number.

## Practice in the 2026 Step 2 CK format

If your Step 2 CK is still ahead of you, this site's [Step 2 CK practice test](https://meduniexam.com/exam/usmle-step-2-ck.md) gives one free 30 minute block of 20 new questions in the 2026 format, with explanations; full 316 question mocks are paid.

Pass rates, attempt limits and what the score report shows are in [Step 2 CK percentiles and the 218 pass score](https://meduniexam.com/blog/step-2-ck-percentiles-and-passing-score.md).

## Sources for the numbers on this page

- [USMLE Score Interpretation Guidelines](https://www.usmle.org/sites/default/files/2022-05/USMLE%20Step%20Examination%20Score%20Interpretation%20Guidelines_5_24_22_0.pdf), updated August 17, 2026, the date at the foot of every page of the file, read November 4, 2026. Its address still carries 2022-05 in its path; it is the current file.
- [USMLE Examination Results and Scoring](https://www.usmle.org/scores-transcripts/examination-results-and-scoring), for the minimum passing scores and Step 1's pass or fail reporting, read November 4, 2026.

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## Sources

The outside pages this page links to, in the order they first appear.

- [USMLE Score Interpretation Guidelines](https://www.usmle.org/sites/default/files/2022-05/USMLE%20Step%20Examination%20Score%20Interpretation%20Guidelines_5_24_22_0.pdf)
- [USMLE Examination Results and Scoring](https://www.usmle.org/scores-transcripts/examination-results-and-scoring)

## Related pages

- [Step 2 CK Percentiles 2026 and 218 Pass Score](https://meduniexam.com/blog/step-2-ck-percentiles-and-passing-score.md): Every Step 2 CK percentile from a score of 205 up to 280 in one table, with the national mean by academic year, the passing score of 218 and the pass rate for each examinee group, all checked on September 21, 2026.
- [USMLE Step 3 Pass Rate, Passing Score and Fee](https://meduniexam.com/blog/usmle-step-3-pass-rate-passing-score-and-fees.md): Step 3 first time pass rates for US MD, US DO and non-US graduates from 2020 to 2025, the 200 passing score on the 1 to 300 scale, the 227 mean with percentiles, the two day format, the USD 955 fee and when scores arrive.
- [NBME Shelf Exam Scores, Percentiles and Timing](https://meduniexam.com/blog/nbme-shelf-exams-scores-percentiles-and-dates.md): How NBME clinical science shelf exams work: 110 questions in 2 hours 45 minutes, equated percent correct scores from 0 to 100, academic year and quarterly norms that go to schools rather than the public, result timing, 2026-2027 fees and the contrast with Step 2 CK.
- [Match 2027 Timeline: ERAS and NRMP Dates](https://meduniexam.com/blog/residency-match-2027-timeline-eras-and-nrmp-dates.md): Every date of the 2027 residency Match from the AAMC ERAS timeline and the NRMP applicant calendar, the ERAS and NRMP fees, Match Week and SOAP hour by hour.