In this guide
What the ISEB Pre-Test actually is
The ISEB Common Pre-Test is an online, age-standardised reasoning test administered by the Independent Schools Examination Board. Introduced in 2010, it is the single most common pre-test for entry to British senior independent schools at age 13 (Year 9). Despite the word "common", the test is not common entrance. It does not test taught curriculum content; it tests reasoning ability.
Senior schools want a way to assess prospective Year 9 pupils consistently, two to three years before the children actually arrive. Because the Pre-Test is standardised by age in months and delivered identically to every candidate, it gives schools a comparable signal across hundreds of children sitting from very different prep schools, including children educated overseas in non-British systems. For international families that matters most: a child in Year 6 in Dubai on a US curriculum can be compared like-for-like with a UK-prep applicant.
Which schools use it
About 80 senior independent schools accept the ISEB Common Pre-Test as part of their 13+ admissions process. The roster includes the most selective schools in the UK: Eton, Harrow, Winchester, Westminster, St Paul's, Tonbridge, Charterhouse, Wycombe Abbey, Cheltenham Ladies', Sevenoaks and most of the others a UK boarding family would consider. Many day independents in London (Westminster, City of London, Latymer Upper, KCS Wimbledon) also use it for 11+ or 13+ entry. For broader UK-bound options see our piece on UK boarding schools for international families.
Not every senior school uses the Pre-Test, and a small number that do also require an additional school-specific paper. Eton, for example, layers the Eton Test on top. Westminster runs its own Challenge. The Pre-Test result is the floor; the school's own paper sits above it.
Crucially, the Pre-Test is sat once, and the result is then shared with up to six senior schools that the family registers in advance. This is the single most important logistical fact for an international family: choose the six target schools before the test, because you cannot easily share the result later with a school that was not on the original list.
Format and four reasoning sections
The Pre-Test is delivered online in four adaptive sections. Each section lasts about 25 minutes, and the full sitting is roughly two hours including instructions and a short break. The four sections are:
Verbal reasoning. Word relationships, analogies, vocabulary in context. This is the section most influenced by reading habits at home. A child who has read across a broad range of fiction and non-fiction will be at an advantage here.
Non-verbal reasoning. Pattern, shape, sequence and matrix questions. Culturally fair and language-light. For EAL children this is usually the strongest section relative to verbal.
Mathematics. Worth noting that this is the only section that does test taught content. The maths section follows the Key Stage 2 syllabus up to the end of Year 6. International children on different maths curricula should walk through the Key Stage 2 maths topics before sitting.
English. Comprehension and grammar. Reading passages followed by inference, vocabulary and grammar questions. Sits alongside the verbal reasoning as the most language-dependent section.
Free download
Our ISEB Pre-Test family briefing covers the four section formats, the Key Stage 2 maths topics most often missed by US-curriculum candidates, and the registration steps for sitting from overseas. Included in our free city handbooks for London, Singapore, Hong Kong and Dubai.
Registering and sitting from overseas
The Pre-Test can be sat three ways from outside the UK. First, at the child's current school if it is a British-curriculum school registered with ISEB. Most BSO-accredited British schools in Singapore, Hong Kong, Dubai, Geneva and major expat hubs can deliver it on-site. Speak to the head of admissions early in Year 6 to confirm.
Second, at a registered British school overseas other than the child's own. Many British schools in major capitals accept external candidates for ISEB sittings for a fee. This is the most common route for international children at non-British schools. Third, at a Pearson VUE testing centre, the global infrastructure ISEB uses for proctored remote delivery. The child sits at the testing centre under ISEB protocols. This is typically the route for families in cities without a registered British school nearby.
When to take it
For 13+ Year 9 entry, the Pre-Test is sat between September and December of the year the child is in Year 6 (ages 10 to 11). The most common window is November. The result is then released to the family and to the registered senior schools in January, well before the senior schools' offer cycle in February.
The most common scheduling mistake international families make is leaving the registration too late. Pearson VUE slots in major expat cities fill quickly between October and December. We recommend registering by the end of September of Year 6, even if you intend to sit in late November. For more on admissions timing across all major destinations, see our admissions timing by city guide.
An 11+ version of the Pre-Test exists for entry to senior schools at 11 (rather than the more common 13+ route). It uses the same four sections but at an age-appropriate standard. The 11+ Pre-Test is sat in autumn of Year 5.
How the scores are used
Each section is reported as a Standardised Age Score (SAS), where 100 is the average for the child's age in months. Senior schools receive the SAS for each of the four sections plus the mean. They do not see how the child compares to peers at any single school, only against the national age-norm population.
The schools then apply their own thresholds. Eton, Westminster, St Paul's and the most selective Russell Group feeders typically look for a mean SAS of around 115 to 120 with all four sections above 110. Schools at the second tier of selectivity often look for around 110 with all sections above 100. Schools that use the Pre-Test as a floor rather than a filter set the bar lower, often around 100.
The score is one piece of the admissions picture. It sits alongside the prep school head's reference, an interview, and (in many cases) a school-specific paper. A strong Pre-Test does not guarantee an offer. A weak Pre-Test rarely overturns an otherwise outstanding application at less selective schools, but at the top tier it usually does.
| Tier | Indicative mean SAS | Example schools |
|---|---|---|
| Top selectivity | 118 to 125+ | Eton, Westminster, St Paul's, Wycombe Abbey |
| High selectivity | 112 to 118 | Harrow, Charterhouse, Tonbridge, Sevenoaks |
| Selective | 105 to 112 | Marlborough, Uppingham, Cheltenham College |
| Floor-only | 95 to 105 | Various day independents, broader-intake boarding |
Sensible preparation
The Pre-Test sits between aptitude test and attainment test. The two language-heavy sections (verbal reasoning and English) reward sustained reading over years. The maths section rewards the Key Stage 2 curriculum. The non-verbal section is the closest to a pure aptitude test, although familiarisation reliably adds 3 to 5 SAS points.
For international children at non-British curricula, the highest-yield preparation is maths topic coverage. Children on the US curriculum may not have covered ratio, percentage of an amount, basic algebra, perimeter and area conversions in the order Key Stage 2 introduces them. A four to six month walkthrough of the Key Stage 2 maths syllabus before the autumn sitting is the single best preparation investment. For verbal reasoning and English, sustained reading is the highest-yield preparation; reading levels rather than tutoring drive the score.
Excessive coaching is counterproductive. The Pre-Test is sat once, and the senior school meets the child a few months later at interview. A child whose score is well above their lived ability will not survive interview, and senior schools are skilled at spotting the gap. Worse, an over-coached child often arrives in Year 9 unable to keep up with the cohort the score has placed them in.
After the result lands
The result is released in January via the ISEB portal. The family and the registered senior schools see it at the same time. Most senior schools then move to interview and offer in February and March. International families should plan to be available in the UK for interviews in late January or February.
If the result is weaker than hoped, the practical question is whether to add a school to the application list. Adding a school after the Pre-Test sitting is possible but limited; ISEB will share the existing result with the new school for a fee, but only within a defined window. Move quickly if you need to broaden the list.
If the result is stronger than expected, the most useful conversation is with the prep school head, who has the discretion to write an upgraded reference that matches. The reference and the Pre-Test together are usually what carry the application at top-tier schools.
For international families wider considerations apply, especially if there is no immediate plan to relocate to the UK. The related guide on the CAT4 admissions test covers the parallel cognitive assessment many overseas international schools also use. Tie the two together when planning Year 6 if you are keeping options open.
Frequently asked questions
At what age is the ISEB Common Pre-Test taken?
Most children take it in Year 6 or Year 7 (ages 10 to 12), typically between September and December of the year before Year 9 entry to a senior independent school. An 11+ version exists for entry at age 11.
Can the ISEB Common Pre-Test be taken outside the UK?
Yes. The test is delivered online and can be sat at the family's current school (if it is a registered British school), at another registered British school overseas, or at an approved Pearson VUE centre in most major expat cities.
Is the ISEB Common Pre-Test the same as the ISEB Common Entrance?
No. The Pre-Test is a reasoning and cognitive assessment at age 10 or 11. The Common Entrance is a curriculum-based exam at 13 in core subjects like English, maths and science. Most senior schools now treat the Pre-Test as the main gating assessment.
How much preparation is sensible?
Familiarisation with the four section formats is useful. Walking through the Key Stage 2 maths syllabus is high yield for international children on non-British curricula. Heavy long-term coaching tends to depress later attainment because it inflates the score above the child's natural level.
Can a child re-sit the Pre-Test?
Not in the same admissions year. ISEB allows one sitting per cycle. The exception is documented illness or technical failure at the original sitting, in which case ISEB will issue a re-sit.