This is the question that comes up more than almost any other when parents first start researching prep school admissions. And honestly? The confusion is understandable. The two paths look similar on the surface but they're fundamentally different commitments — and choosing between them before you fully understand both is how families end up missing deadlines.
The 11+ route leads to senior school at Year 7. The 13+ route adds two more years at prep school, with the red badge marking the Year 5 registration deadline — the most commonly missed date in the whole process.
Neither path is better. Neither path is harder. They're just different — and the right one depends on your child, your geography, and which senior schools you're aiming for.
What the two pathways actually mean
11+ entry (Year 7) means your child moves to senior school at age 11, at the end of Year 6. They sit entrance exams — usually school-specific papers, not a single national exam — in the autumn and winter of Year 6. Offers come in January or February.
13+ entry (Year 9) means your child stays at prep school until the end of Year 8, then moves to senior school at age 13. The process begins much earlier: registration with senior schools should happen by June of Year 5, and the ISEB Common Pre-Test is sat in October or November of Year 6.
The timeline gap that surprises people
The 13+ registration deadline (June, Year 5) arrives before most children have begun Year 6. Yet 11+ exam preparation typically runs through Year 5 and Year 6. Families targeting both paths simultaneously face a compressed and stressful timeline — children may be sitting 11+ exams in October while also taking the ISEB Pre-Test for 13+ entry in November of the same term.
The geography factor
Geography is probably the single most important factor in this decision, and it's the one least often discussed.
London and its immediate commuter belt: The 11+ route dominates. London's top day schools — including North London Collegiate, City of London School for Girls, St Paul's School, Highgate, and University College School — all take their main or entire intake at Year 7. If you're in London and you want a day school, you're almost certainly looking at 11+ entry.
Outside London, particularly in the boarding school heartlands: The 13+ route via Common Entrance is the traditional norm. Schools in the south-west, home counties, and Midlands that feed into Eton, Harrow, Winchester, Marlborough, and similar schools typically expect boys and girls to complete prep school at 13+.
Co-educational day schools in the south-east: Often a mix — check each school individually, as patterns are shifting. Some schools that traditionally took 13+ entry are moving to 11+, and vice versa.
Why boarding schools anchor around 13+
The 13+ route exists largely because of the boarding school tradition. The great English boarding schools — Eton, Harrow, Winchester, Rugby, Charterhouse, Marlborough, Radley, Oundle, and Tonbridge among them — were built around an intake of 13-year-olds completing their prep school education. Common Entrance was designed specifically to serve this transition.
Westminster School is worth noting separately. Although it sits in central London rather than the countryside, it is one of the most academically selective boarding and day schools in the country and takes a significant proportion of its intake at 13+ via its own entrance papers rather than standard Common Entrance. It also takes some pupils at 11+.
That said, the boarding world is not uniform — and it is not only for academic high-achievers. Here is a more complete picture of how different boarding schools approach entry:
- Eton College (Berkshire) — 13+ only, via its own King's Scholarship exam or Common Entrance. One of the most academically and socially selective schools in the world.
- Harrow School (London) — 13+ entry. Strong academically and known for producing prime ministers and global leaders.
- Winchester College (Hampshire) — 13+ entry via its own notoriously demanding entrance papers. Among the most intellectually rigorous schools in the country.
- Rugby School (Warwickshire) — predominantly 13+, with some flexibility. Co-educational, historic, and increasingly international.
- Marlborough College (Wiltshire) — 13+ entry, co-educational, strong academically and in the arts.
- Oundle School (Northamptonshire) — mainly 13+ but has an 11+ entry point for its junior house.
- Uppingham School (Rutland) — takes a small number of pupils at 11+ in addition to its main 13+ intake.
- Haileybury (Hertfordshire) — admits pupils from age 11, making it one of the more accessible entry points into boarding.
- Sevenoaks School (Kent) — takes both 11+ and 13+ and is known for the International Baccalaureate rather than A-levels.
- Bryanston School (Dorset) — 13+ entry, known for a more progressive and creative approach to education.
- Bedales School (Hampshire) — 13+ entry, strongly arts and outdoors focused, popular with families who want something less traditional.
- Millfield School (Somerset) — takes pupils from Year 7 (age 11) as well as at 13+, making it one of the more flexible boarding entry points. Millfield is particularly well known for sport — it has produced more Olympic athletes than almost any other school in the UK, and its facilities and coaching are exceptional. It is not primarily an academic hothouse, which makes it a genuinely different kind of option for sporty, talented children who might not thrive in a purely academic environment.
The key takeaway: boarding school is not a single category. There is a boarding school for almost every kind of child — academically driven, creatively inclined, sporty, or somewhere in between. The entry point, the ethos, and the environment vary enormously. Visit before you decide — our prep school open days guide covers what to look for on each visit.
The ISEB Pre-Test explained
For families on the 13+ path, the ISEB Common Pre-Test is the most consequential assessment before Common Entrance itself.
It's a computer-adaptive test, meaning the questions get harder or easier based on your child's performance in real time. It typically takes around two hours and covers English (reading comprehension and writing), Mathematics, verbal reasoning, and non-verbal reasoning.
The Pre-Test is sat at your child's current school in October or November of Year 6. It can't be rescheduled for individual pupils. Senior schools use the results to issue conditional offers — usually specifying the grade threshold required at Common Entrance to convert that offer into a firm place.
Most selective schools weight the Pre-Test heavily. Proper preparation should begin in Year 5 at the latest.
Common Entrance: what it actually involves
Common Entrance is sat in May and June of Year 8, when your child is 12 or 13 years old. It's set by ISEB and marked by the receiving senior school — not by ISEB.
Subjects at 13+:
- English (two or three papers: comprehension, composition, and sometimes literature)
- Mathematics (two papers)
- Science (one or two papers)
- French or Spanish
- Latin (optional but expected at some schools)
- History, Geography, or Religious Studies (optional; increasingly expected at selective schools)
Each senior school sets its own minimum grade threshold. Some schools set 55%; others require 65% or higher across all subjects. Selective schools such as Winchester set their own papers in addition to CE — or instead of it.
A framework for your decision
Factors that point toward 11+ entry
- You are based in London or the immediate commuter belt, where the top day schools take their main intake at Year 7
- Your preferred senior schools are day schools rather than boarding schools
- Your child is socially ready to move on at 11 — some children thrive with an earlier transition
- Your child's prep school ends at Year 6, making 13+ entry impractical without changing schools
- You want to avoid the Year 5 ISEB Pre-Test registration pressure and the two-year conditional offer period
- Your child is a strong all-round performer who suits school-specific entrance papers rather than the subject-by-subject Common Entrance structure
- Your child is coming from overseas and you want them to settle into the UK system gradually — 11+ gives them more time to adjust before the academic pressure of senior school increases
- You are an international family and prefer your child to be closer to a large city with good transport links — many 11+ day schools are in or near London, making visits and travel more manageable
- Your child is sporty or has a particular talent — schools like Millfield in Somerset take pupils from Year 7 (11+ entry) and are renowned for specialist coaching in sport, music, and the performing arts, making them a strong option regardless of which entry route you are considering
Factors that point toward 13+ entry
- Your ambition is a traditional English boarding school — Eton, Harrow, Winchester, Rugby, Marlborough, or similar
- Your child's prep school runs to Year 8 and is geared toward Common Entrance preparation
- Your child is on the younger or less mature side at 11 — two extra years at prep school can make a meaningful difference
- You are outside London, where the 13+ boarding school pathway is the cultural norm
- Your child excels in specific subjects and would benefit from the subject-by-subject Common Entrance structure
- You have already registered with senior schools by the end of Year 5 — if you have not, act immediately
- You are an international family and 13+ means two more years at home with your child before they leave for the UK — for families based overseas, that time together matters enormously, and many consciously choose 13+ for exactly this reason
- The separation of sending a child to board in another country is significant — 13+ entry at age 13 rather than 11 gives your child two more years to grow, mature, and build the independence they will need before making that transition
The hidden cost of leaving it too late
Here's where this becomes urgent: the 13+ registration deadline can't be missed.
Most parents who discover they should have been on the 13+ path do so in Year 6 or Year 7 — when the deadlines have already passed. Senior schools aren't obliged to accept late registrations. Some will consider them on a case-by-case basis; the most competitive schools won't. If you're further along than the ideal timeline — or already past a published deadline — the piece on boarding school late applications covers what's still genuinely possible.
If there's any possibility your child will pursue 13+ entry, register by the end of Year 5. The registration fee is typically £100–£480, depending on the school. Some of the most selective senior schools charge toward the higher end, and some provincial schools come in lower — if you are registering with several schools, budget £300–£480 per application to be safe. It's the cheapest insurance policy in education. For a full breakdown of what these totals look like in practice — including boarding, extras, and travel costs — see our complete prep school fee guide.
That's where preptimely comes in. You've just read the map — we help you follow it.
If your child is joining from overseas
Everything above assumes your child is already in the UK school system. If they're not — if you're relocating from abroad, or if your child has been schooled internationally and you're considering UK boarding — the timeline looks meaningfully different, and the preparation required is greater.
Start earlier than you think you need to.
Most families in this situation underestimate how much groundwork is involved before a single application is submitted. Here is what that groundwork actually looks like:
Academic alignment UK independent schools, particularly at 13+, expect a specific curriculum foundation. A child schooled in the International Baccalaureate Primary Years Programme, the American system, or the French system will need time to bridge into the UK model — especially in maths, English grammar, and essay writing. Many families engage a UK-based tutor twelve to eighteen months before the target entry date specifically for this alignment work.
English language preparation If English is not your child's first language, most schools will require evidence of English proficiency — typically an IELTS or ISE qualification, or their own internal assessment. This takes time to prepare for properly. Factor in at least six months of dedicated preparation, often more.
Guardianship Most boarding schools require international families to appoint a UK-based guardian before your child can be offered a place. Your child will be living and studying in the UK — the guardian is simply the trusted adult the school can reach when you're not in the country.
Guardianship agencies are the most common solution — look for providers registered with AEGIS or affiliated with the ISA.
Visa and paperwork Depending on your child's nationality and your family's residency status, a visa may be required. The school you choose will have a dedicated admissions team who handle this regularly — contact them early and follow their guidance. Every school's process is slightly different, and they are well practised at walking families through it.
The timeline for international families — a rough guide
If your child is aiming for 13+ entry at a UK boarding school:
- 2–3 years before entry: Begin school research, engage a UK education consultant if needed, start academic alignment and English preparation
- 2 years before entry (Year 5 equivalent): Register with target senior schools by 30 June. Appoint a guardian.
- 18 months before entry: Sit ISEB Common Pre-Test in October–November
- 12 months before entry: Conditional offer received. Begin Common Entrance subject preparation in earnest.
- 6 months before entry: Apply for Child Student Visa once CAS number is issued
- Entry: Year 9, age 13
If your child is aiming for 11+ entry, compress this timeline by two years — but the preparation steps remain the same. The visa, guardianship, and English language requirements don't shorten just because the entry point is earlier.
Working with a UK-based independent schools consultant is often a genuinely good idea for international families — someone who knows the landscape, knows the schools, and can guide you through the nuances that don't appear in any prospectus.
And once you have the right people around you, having the right tools helps too. Keeping track of registration deadlines, pre-test windows, and open day seasons across multiple schools and time zones is exactly the kind of thing that slips. That's what preptimely is for — so the timeline piece, at least, is one less thing to carry.
Whether your child is already in a UK prep school or still at home overseas, the first step is the same — see exactly which deadlines apply to their date of birth.
See when your child's deadlines actually fall
preptimely calculates every registration window, exam season, and open day period based on your child's birthday. See the full picture in seconds — no account required.
Check my child's timeline →