How Many Postcodes Are There in the UK?

The UK has approximately 1.8 million active postcode units. That figure covers the full postcode — for example, LS1 4DY — which identifies a small group of addresses, typically a single street segment or part of a building. But postcodes exist at four levels, each with its own count, and the number that matters most depends on what you are trying to do with them.

Here is the breakdown across all four levels:

Postcode Areas: 124

The UK is divided into 124 postcode areas, each identified by one or two letters. These are the broadest level of postcode geography: LS covers the entire Leeds delivery area, M covers Greater Manchester, and IV covers an enormous swathe of the Scottish Highlands.

The 124 areas include coverage for mainland Great Britain, Northern Ireland, the Channel Islands (GY for Guernsey, JE for Jersey), and the Isle of Man (IM). London is divided into multiple areas: the central areas (EC, WC, E, N, NW, W, SW, SE) plus a ring of outer areas (BR, CR, DA, EN, HA, IG, KT, RM, SM, TW, UB, WD).

For national business planning, 124 is a manageable number. A sales director can look at a UK postcode area map and immediately understand the national picture: where customers are, which areas a team covers, and where there are gaps.

Postcode Districts: Around 3,000

Each postcode area is subdivided into postcode districts, formed by adding a number to the area letters: LS1, LS2, M1, M60, SW1, SW19. The total across the UK is approximately 3,000 districts, though this changes slightly as new districts are created for large developments or retired when areas are reorganised.

District counts within each area vary considerably. London's SW area has districts running from SW1 to SW20; the IV area in northern Scotland has districts up to IV63. The number of districts in an area reflects the density of addresses it contains: dense urban areas have many small districts, while rural areas have fewer, larger ones.

For field sales territory planning, postcode districts are the most commonly used unit. At around 3,000 across the UK, they are granular enough to allow fair and meaningful territory division while being large enough for each one to represent a genuine geographic patch.

Postcode Sectors: Around 11,000

Postcode sectors are formed by adding a single digit to the district: LS1 1, LS1 2, LS1 3. There are approximately 11,000 postcode sectors across the UK. Each sector typically covers a few thousand delivery points, representing a realistic workload for a single postal delivery round.

Sectors are the finest level shown on printed postcode maps and the standard unit for direct mail planning. Royal Mail plans its Door to Door and addressed mail products at sector level, and most data providers price and count their records by sector.

For businesses running local or regional campaigns, 11,000 sectors gives enough granularity to target specific neighbourhoods within a town or city. A retailer in Sheffield wanting to target households within a 5-mile radius can select specific sectors on a map and request counts for each, rather than having to work with a full district that may extend well beyond their catchment.

Postcode Units: Around 1.8 Million

The full postcode — also called the postcode unit — is what most people mean when they say "a postcode." There are approximately 1.8 million active postcode units in the UK, covering around 29 million delivery addresses.

Each postcode unit covers a small cluster of addresses: the average is around 15 to 20 delivery points, though this varies enormously. A rural lane might have a single postcode covering a handful of farms; a large city-centre office block may have its own dedicated postcode covering hundreds of individual businesses.

Postcode units are not shown on printed maps because 1.8 million boundaries would be unreadably dense at any useful scale. They are used in databases, CRM systems, address lookups, and precise geographic analysis. Any address can be matched to a postcode unit, and any postcode unit can be converted to a National Grid reference, placing it on a map to within a few metres.

How the Count Changes Over Time

The number of active postcodes is not fixed. Royal Mail adds new postcode units as housing developments and commercial properties are built, and retires postcodes when properties are demolished or consolidated. Approximately 2,500 to 4,000 postcode units are created or terminated each year, meaning the total shifts slightly from quarter to quarter.

At the higher levels, changes are rarer. New postcode districts are occasionally created when a town grows significantly, and postcode areas are almost never added or changed. The 124-area structure has been largely stable for decades, with only minor adjustments as the postal network has evolved.

For business users, this means that any postcode-based database, CRM, or territory structure needs periodic updating to reflect the current postcode universe. A territory defined in 2020 using a list of districts will still be valid today, but a customer database of full postcode units may contain a small number of retired codes that no longer match active addresses.

Terminated and Non-Geographic Postcodes

Not all postcodes in existence are active delivery addresses. Royal Mail maintains a record of terminated postcodes: codes that were once active but have been retired. These remain in some databases and can cause issues for businesses geocoding their customer records if the data has not been cleaned recently.

There are also non-geographic postcodes: codes assigned to high-volume mail recipients such as large government departments, financial institutions, and some charities. These do not correspond to a physical street address and cannot be plotted on a map in the usual way. The GIR 0AA postcode (formerly used by the National Girobank) is the best-known example.

For mapping and territory planning purposes, non-geographic and terminated postcodes should be excluded from any geographic analysis.

What This Means for Mapping

The four-level hierarchy gives businesses a choice of resolution depending on their needs:

• 124 areas for national strategic planning and broad regional division
• ~3,000 districts for field sales territory design and logistics planning
• ~11,000 sectors for direct mail targeting and granular urban territory work
• ~1.8 million units for precise address-level geocoding and CRM data management

UK Maps produces postcode boundary maps at area, district, and sector level, all based on Ordnance Survey data under licence number AC0000848283. These are available as instant PDF downloads for the full UK or for specific regions and cities.

• UK Postcode Area Map — all 124 postcode areas on a single map
• Postcode District Maps — national and regional views at district level
• Postcode Sector Maps — city and regional maps at sector level for direct mail and territory planning

All maps are supplied as 300 DPI PDFs ready to print at A1 or larger.

Related: The Complete Guide to UK Postcode Geography — a full explanation of how the postcode system is structured and how each level is used.