The UK postcode system is one of the most granular addressing systems in the world, but its four levels are often confused. Here is a clear explanation of what each level means, how many exist, and which one to use for different research purposes.
The Four Levels
1. Postcode Area
Example: GU
The postcode area is the broadest level — a two-letter code covering a large geographic zone, usually centred on a major town or city. There are 124 postcode areas in the UK.
GU covers Guildford and a large part of Surrey. SW covers South West London. M covers Manchester.
Use for: Very broad regional comparisons. Too large for meaningful area research.
2. Postcode District
Example: GU1
The postcode district adds a number to narrow the area to a town, a borough, or a major part of a city. There are approximately 3,000 postcode districts in the UK.
GU1 covers central Guildford and the surrounding area. SW1A covers Westminster. M1 covers central Manchester.
This is the most useful level for area research — it is small enough to be meaningful but large enough to have statistically robust data on house prices, crime, schools, and demographics.
Use for: House price research, crime comparison, school ratings, broadband speeds, council tax rates, demographic data. This is the primary level used by Postcode.Page.
3. Postcode Sector
Example: GU1 3
The postcode sector adds the first number of the inward code to narrow to a street or neighbourhood cluster. There are approximately 11,000 postcode sectors in the UK.
GU1 3 covers a specific cluster of streets in central Guildford. This level has enough transactions to calculate meaningful average house prices but not enough for reliable crime or school statistics.
Use for: Granular house price research within a district you have already shortlisted. Postcode.page provides sector-level price data where enough Land Registry transactions exist.
4. Full Postcode
Example: GU1 3BT
The full postcode — district + sector + two letters — identifies a specific delivery point: typically a side of a street, a cluster of houses, or a building. There are approximately 1.8 million active full postcodes in the UK, each covering an average of 15 addresses.
Use for: Finding specific addresses. Too granular for reliable statistical analysis — there may be only 5–20 property sales at a full postcode in any given year.
Which Level Should You Use?
| Purpose | Best level |
|---|---|
| Comparing different towns or areas | District |
| House price research for an area you are considering | District, then Sector |
| Crime, schools, demographics, council tax | District |
| Checking a specific property’s price context | Sector |
| Searching for an address | Full postcode |
How Postcode.page Uses Each Level
- District pages (e.g. /gu1/): Full data — prices, crime, schools, broadband, demographics, council tax, comparisons
- Sector pages (e.g. /gu1/3/): House price data only — average, by type, 5-year history
- Region and county pages: Aggregated from district data, showing district rankings within a geographic area
For area research, start at district level. Once you have a specific street in mind, use the sector page to check whether that micro-market is priced in line with the district average or commands a premium.