What UK bus route numbers mean

The number on the front of the bus is not a national code. It is chosen locally, it is reused constantly, and most of what people believe about the letters is folklore. Three patterns do hold up — and one of them is worth trusting.

Nobody assigns them nationally

There is no national register of bus route numbers in Britain. The operator picks the number, or the local transport authority picks it when it tenders the service; in London, Transport for London specifies the route and its number. Operators then register the service itself — its route, timetable and any change to either — with a Traffic Commissioner, and publish the timetable through the Department for Transport's Bus Open Data Service, which is where the times on this site come from.

What gets registered is the service, not the number. Nothing stops two towns three hundred miles apart both running a 1, and plenty do. As of September 2026 there are 13,984 bus routes in our timetable database using 3,394 different designations — and 1,646 of those designations are shared by more than one route.

The most reused numbers

Each links to that number's disambiguation page, which lists every route carrying it by area. Browse all 1,646 shared numbers.

N usually means night — and it is the one letter to trust

Of the 205 routes whose number starts with N, 81% run between midnight and dawn. That is by far the strongest signal any letter carries. London's are the familiar ones — the N15 from Romford to Oxford Circus and the N29 from Enfield Town to Charing Cross both start just after midnight — but the pattern holds well outside London: Brighton's own N29 from Old Steine runs 01:15 to 04:43.

The reverse does not hold, and this is where people get stranded. Only about one night bus in seven carries an N: of roughly 1,200 routes running after midnight across the UK and Ireland, just 167 are N-prefixed. Most of London's night service runs on ordinary daytime numbers. A plain number tells you nothing about whether it stops at 23:00 — check the route, or see night buses by town.

X usually means express, or simply further

An X at the front marks a faster or longer-distance version of a corridor: it skips intermediate stops, or it carries on past where the ordinary route turns round. The data bears this out — across 536 X-prefixed routes the average one serves 12.9 places against 9.8 for a plain-numbered route, while running fewer journeys a day.

The extremes are rural rather than urban. The X95 between Galashiels and Hawick and the X99 from Inverness to Scrabster each touch 40 separate places on a single run. An X on a town service usually just means it misses a housing estate the ordinary number goes round.

S at the end usually means school

107 routes end in S, and they behave nothing like ordinary services: an average of 5 journeys on a weekday against 40.6 for the network as a whole, and many run once each way. Several name the school as the terminus — the 45S runs from Irthlingborough to Irthlingborough Huxlow School, one journey a day. These usually do not run in school holidays.

The letters that mean nothing in particular

A trailing letter normally marks a variant of the same core route — a different terminus, a peak-hour extension, one direction of a loop — and what it stands for is the operator's business, not a convention. 242 routes end in C, and despite the common belief that C means circular, our timetable data shows no such pattern: they are ordinary variants.

Treat any trailing letter as "this is not quite the same route as the plain number" and check the specific service. On a 4 and a 4C, the useful question is never what the C means — it is which one stops where you are going.

Leading zeros are real — don't strip them

A handful of services are registered with a padded number, and it is part of the number rather than a formatting accident. Diamond Bus runs the 002 from Castle Square to Merry Hill Centre. National Express coach services are numbered this way throughout — the 025 is Brighton to London Victoria, the 040 is Bristol to London Victoria. Searching for "2" or "40" will not find them.

How to find the right one

• Start from bus timetables by route number, then pick your area — every shared number has a page listing each route that carries it, with the towns it runs between.
• If you know the stop, search the stop name instead. That gives live departures from that exact stop, which beats any timetable.
• If you know the towns but not the number, use timetables by town.

Common questions

Are UK bus route numbers unique?

No. Route numbers are chosen by the operator or the local transport authority, not from any national list, so the same number is reused all over the country. Of 3,394 different route designations in use across the UK and Ireland, 1,646 are used by more than one service — there are 127 different number 1 buses alone.

What does the N mean on a bus number?

An N at the front usually means a night service, and it is the most reliable letter on a British bus: 205 routes start with N and 81% of them run between midnight and dawn. The reverse is not true — only about one night bus in seven carries an N, so never assume a plain number stops at midnight.

What does the X mean on a bus number?

An X usually marks an express or longer-distance version of a route: it skips stops, or runs further. Across 536 X-prefixed routes the average one serves 12.9 places against 9.8 for a plain-numbered route, on fewer journeys a day.

Why does my bus number end in a letter?

A trailing letter almost always marks a variant of the same core route — a different terminus, a school journey, or a peak-hour extension. Only S is consistent nationally (school services). Others, including C, vary by operator, so check the specific route rather than assuming.

Figures counted across every route in our timetable database in September 2026, built from operators' own registrations via the DfT Bus Open Data Service — see all data sources. Route numbering is set locally and changes with each registration, so treat the percentages as the shape of the network rather than a rule.