The rates, and the date on them
April 2025 pass rates as a benchmark (they are fairly even across years):
| Subject | April 2025 pass rate |
|---|---|
| CS1 | 44% |
| CS2 | 48% |
| CM1 | 40% |
| CM2 | 48% |
| CB1 | 59% |
| CB2 | 63% |
| CP1 | 44% |
| 59% | |
| 53% | |
| SP | 44% |
| SA | 41% |
| Overall | 48% |
The working range across recent sittings is roughly 35%–65% per subject, with the mathematical core hardest and the business subjects most passable.
One line of arithmetic
If every attempt at a subject passes with the same probability p, and attempts are independent, then the expected number of attempts to get one pass is 1 divided by p.
| Subject | Entry fee | April 2025 rate | Expected attempts, 1 ÷ p |
|---|---|---|---|
| CS1 | £375 | 44% | 2.27 |
| CS2 | £375 | 48% | 2.08 |
| CM1 | £375 | 40% | 2.50 |
| CM2 | £375 | 48% | 2.08 |
| CB1 | £302 | 59% | 1.69 |
| CB2 | £302 | 63% | 1.59 |
| CB3 | £701 | none published | 1.00 |
| CP1 | £786 | 44% | 2.27 |
| CP2 | £623 | 59% | 1.69 |
| CP3 | £423 | 53% | 1.89 |
| SP, the first | £423 | 44% | 2.27 |
| SP, the second | £423 | 44% | 2.27 |
| SA | £423 | 41% | 2.44 |
| All thirteen | £5,906 | 26 |
CB3 is the one row that is not a coin flip. It is a self-paced course rather than an exam, publishes no pass rate, and is counted once.
Expected attempts of about 26 to clear 13 subjects, so on average you sit everything twice. And 26 attempts at four entries a year is about six and a half years of sittings, which lands squarely inside the four to seven years the profession describes as realistic and six-plus as entirely normal.
Four things the model assumes away
The first flatters you. The other three make the number an estimate rather than a measurement.
Independence is generous. Attempts at different subjects draw on the same finite pool of evenings and weekends. A season loaded with two hard subjects tends to go worse than independence implies, not better, because the study hours are shared and the calendar is not.
A constant p is a simplification. It assumes the sitting you fail teaches you nothing and costs you nothing, when in practice a fail can move your rate in either direction: better prepared next time, or a subject you have started to dread.
The cohort rate is not your rate. These percentages describe everybody who sat that session. You are one person with a specific number of study days, a specific starting point, and a specific employer.
And the pass rates themselves move. There is no fixed pass mark. The Chief Examiner agrees one each session according to paper difficulty. A pass rate is partly an artefact of where that line landed, which is how the CM group could drop from 40% in April to 33% in September without the syllabus changing.
What to do with the number
Budget attempts, not passes. A plan that needs thirteen first-time passes slips the first time you fail one. Two entries a sitting, with one expected to need a resit, is a schedule you can keep.
Ask what your employer funds, in attempts. Some employers fund 2 attempts fully, others just the first and others the first fully and the second in half. Check with your employer to find out how many they fund so you can budget exam fees appropriately.