If you've heard another parent say their child passed the 11+ but didn't get into the school, the catchment area is usually why. It's the most misunderstood part of grammar school admissions, and it catches families out every September.
The honest truth is that catchment rules vary so much from one council to the next that what's true in Slough is irrelevant in Sevenoaks. Get the catchment wrong, and your child can pass the test outright and still not get a place. Get it right, and you'll know whether you're competing on score or on geography long before exam day.
Let me explain how it actually works in plain English.
What "catchment" really means in the 11 plus
A catchment area is the geographic zone a school uses when there are more qualifying children than there are places available. It isn't a guarantee of admission. It's a tiebreaker. Once children pass the qualifying mark, the school has to decide which of those qualified children get the limited places. In most cases, distance from the school decides.
How that distance is measured changes from one school to the next. Some use straight-line distance from the front door of the home to the front door of the school. Some use the shortest safe walking route. A few use postcode bands. A handful of super-selective grammars don't use catchment at all and rank purely by score, which is a different beast altogether.
So when a parent says "we're in catchment", what they usually mean is "we live close enough that, based on last year's admissions, we'd have been offered a place if we passed". That's a useful piece of information. It isn't a promise.
The three different ways catchment gets applied
Different councils handle this differently, and the differences matter.
The simplest version is pure distance. The school sets no formal catchment boundary. Every child who passes is ranked by how far they live from the school, closest first. Children at the top of that list get offers until places run out. Plenty of grammars in Bucks and the Wirral work this way.
The second version is a defined catchment zone. The school draws a boundary, and only children inside that boundary are offered places after passing. Aylesbury Grammar's catchment zone, for instance, is set out on the local authority site and includes specific named villages. Live outside it and your pass might count for nothing unless places remain unfilled, which is rare.
The third version is a multi-stage system. Sutton's grammars use this, and Kent has variants too. Local children inside a defined area are offered places first. Any remaining places go to children who live further out. Two children with identical scores can get different outcomes purely on where they live.
Why catchment changes year to year
Here's the part most parents miss. Catchment isn't a fixed number. It expands and contracts based on how many qualifying children apply from inside the area.
In a year where lots of strong applicants live close to the school, the catchment effectively shrinks. The school fills its places from a smaller radius. In a quieter year, the catchment widens. A child who would have been just outside in 2023 might be comfortably in by 2025.
This is why "last year's furthest offered distance" matters more than any abstract boundary. You'll often find this figure on a school's admissions page or in the council's published admissions report. It's the most honest read on who actually got in.
How catchment works in the main selective regions
Kent runs on a Kent Test pass plus distance. Most Kent grammars then offer places by distance from the school, with siblings and a few other categories ahead of pure distance. Some Kent grammars have formal designated areas. Others don't.
Buckinghamshire uses one of the cleanest catchment systems in the country. Most Bucks grammars are catchment-only, with specific feeder areas set out by the council. You can pass the test, live thirty miles away, and still not get a place at a Bucks grammar unless places remain. Aylesbury Grammar, Sir Henry Floyd and Royal Latin all run this way.
Birmingham's KEVI consortium (King Edward's, Camp Hill, Five Ways and the others) uses a combination of distance and priority areas. The consortium reserves a chunk of places for children eligible for pupil premium, and the rest go by distance.
Essex grammars all use catchment in slightly different ways. Some draw a circle. Some use a priority area. Southend's two grammars use a banding system that ranks by performance within geographic zones, which is a quirk worth reading up on if you're applying there.
Berkshire is split. The Slough Consortium uses distance and priority areas across its four schools. Reading School and Kendrick don't use catchment at all and rank purely by score. Same county, completely different rules.
In Surrey, Sutton's grammars use a two-stage process. There's a partner schools test, then a final ranking that mixes score and distance. Tiffin in Kingston uses pure distance after a qualifying threshold.
The point is, you can't generalise. You have to look at the specific school.
How to find out where you actually stand
The most reliable source is the local authority's admissions booklet for the year your child will sit the test. It's a dull download and most parents never open it. But it contains the precise oversubscription criteria for every school in the area.
After that, check each school's individual admissions page. Most publish the previous year's furthest offered distance, the qualifying score, and the number of places allocated by each criterion. Read three years' worth of these and you'll have a far better sense of where your postcode sits. Better than any conversation at the school gate.
If you're moving house with this in mind, don't trust an estate agent's claim that a property is "in catchment". Catchment moves. A house that worked in 2022 might not work in 2026. Always check the school's own published distances against the property postcode before you exchange.
When catchment doesn't matter
There are two cases. Super-selective schools that rank purely by score don't use catchment, so live where you like. That includes Reading School, Kendrick, Queen Elizabeth's Barnet, Henrietta Barnett, and Tiffin Girls in some years. The other case is when a school is undersubscribed at the pass level, which is rare in popular areas but happens at the edges. If fewer children pass than there are places, every passing child gets in regardless of distance.
Neither is the norm. For most parents looking at Bucks, Kent, Essex, Birmingham, Slough or Surrey grammars, where you live matters as much as how well your child scores.
What to do with this information
Before you commit to two years of preparation, work out what kind of selective area you're in. If your local grammar is catchment-based and you live well outside last year's furthest offered distance, ask yourself honestly. Is prepping really worth the time?
If you live comfortably inside catchment, prep is about hitting the qualifying score and not stressing about being top of the rank. If you live in a super-selective area, score is everything and catchment is irrelevant. Different game, different strategy.
A baseline benchmark can help here too. Knowing where your child currently sits academically matters. Knowing where you sit geographically matters too. Put the two together and you've got a much clearer read on whether the 11+ is a realistic route for your family.
FAQ
How do I find my school's exact catchment area?
Start with the school's own admissions page and the council's annual admissions booklet for the relevant year. Both will publish the oversubscription criteria and, in many cases, the furthest distance offered a place in the previous year. Avoid third-party catchment maps — they're often out of date by the time you read them.
Can I move into a catchment area just before the test?
Most councils require the address used on the application to be your permanent residence by a published cut-off date, typically October of Year 6. Renting a property short-term to qualify is increasingly detected and rejected. If you're moving genuinely, get the exchange done well before the deadline and use the new address from day one.
Does sibling priority override catchment?
In most areas, yes. A child with a sibling already at the school usually ranks above other applicants regardless of distance, providing they've also passed the test. The exact rules differ by school, but sibling priority is one of the strongest tiebreakers in most admissions criteria.
What if my child passes but we live too far away?
You go through the same offer day as everyone else. If no offer comes from the grammar, you accept your alternative state place. Appeals are possible but rarely succeed on catchment grounds alone. Some families end up on a waiting list, and places do come up later in the year as families above them move or accept other offers.
Knowing where you stand geographically is half the battle. Knowing where your child stands academically is the other half. readyfor11.co.uk gives you a free 20-minute benchmark across reasoning, English and maths. No account, no card. Pair that with a careful read of last year's admissions data for your target school. You'll have a much more realistic sense of whether the 11+ is a route worth taking.