Catchment maps: how they really work — and when not to trust one

Type “school catchment checker” into a search engine and you will find several tools happy to draw a confident line around your address. What those tools rarely explain is where the line comes from — and the answer varies so much that two popular websites can give a family opposite answers about the same house and the same school. This guide explains the three methodologies behind online catchment maps, what each one can and cannot tell you, and how to research an address the way an admissions officer would.

For a distance-tiebreak school, the only number that decided real places is the last distance offered: how far from the school the final successful applicant lived. It moves every year with sibling counts and local demand, which is exactly why it is more honest than a static line. School Atlas holds last-distance-offered figures for Reception and Year 7 at thousands of schools in England, including figures for the September 2026 round as councils publish them. Most come from councils' allocation publications or FOI responses; some were extracted by AI from council documents, and a few have no recorded source. Where a school's cut-off has moved over several years, the trend tells you whether your distance is comfortable, marginal or unrealistic.

School Atlas shows a catchment boundary only when a council has published one — we hold official catchment maps for thousands of schools, each named with the council that published it. Where a council publishes no map, we link its admissions pages, including its postcode checker where it has one, for thousands more schools, rather than inventing a line the council never drew. We do not display estimated boundaries, because a wrong “you're in” is more damaging than an honest “the council publishes no map — here is the real cut-off data instead”.