7 clever ways to create a postcode data catchment area

by Louisa Bainbridge
on Jan 23, 2017

Postcode data is one of the simplest ways to break down and analyse locations. It’s come a long way since the unit was designed by the Royal Mail to ensure they could efficiently sort and deliver post across the UK. For businesses, this data is used to effectively target customers by location, plan distribution routes, or create a catchment area. In this post, I’ll break down some of the key ways you can combine postcode information to make location-based decisions simpler.

The blog has two parts – the first explains postcode groups defined by the Royal Mail. The second explains tools and techniques to generate unique shapes for your specific catchment area purpose.

Royal mail postcode catchment areas

Divide by postcode areas

What is a postcode area?
A postcode area is the first few characters of the postcode. These are large areas that the Royal Mail use to split the UK into different blocks. These are not always the same as a region.

When should you use postcode areas?
Very generic campaigns, analysis or location performance analysis.

Get a postcode area list

Split by postcode districts

What is a postcode district?
The postcode area with 1-2 more characters added. It’s also possible to split these districts by post towns.

When should you use postcode districts?
Generic campaigns, analysis or location performance analysis.

Get a Postcode District List

Narrow down to postcode sectors

What is a postcode sector?
Postcode sectors include the district followed by a space as well as an additional character.

When should you use postcode sectors?
Campaigns and analysis directed as specific areas of the country.

Create a postcode sector map

Focus in on postcode units

What is a postcode unit?
Postcode units add two more characters to the end of the postcode sector to create a full postcode. With a postcode unit you can usually define a location down to a street, this you can define a location down to a street or building.

When should you use postcode units?
Targeting very specific locations e.g. address finder bars on websites or deliveries.

Download all postcode units

Splitting catchment areas

Create postcode catchment areas by travel time


What is a travel time catchment area?
A travel time catchment area is defined up of multiple postcode units, sectors, districts or areas that fall within a set amount of travel time to the point of origin. For example, list all postcode units within 15 minutes travel from my location. Find out more on the launch of the TravelTime postcode tool

When should you use travel time catchment areas?
If the customer or stakeholder needs to travel from a postcode to the point of origin it’s advised to use journey time catchment areas. This means that every postcode listed will be accessible within a certain period of time.


  • Defining which areas are best to advertise a shop’s promo offers
  • Allocating traveling staff to sales territories
  • Understanding how to price courier delivery zones


 Group postcode catchment areas by miles radius


What is a miles-radius catchment area?
When you define a geodistance, such as a 5-mile radius, and download all postcode units, sectors or districts that fall in this area.

When should you use travel time catchment areas?
As miles radius assumes travelers can go as the crow flies it should be used only as an estimate. However as a free tool to guide location decision making.


  • Estimating competition in low-density areas
  • Identifying which postcodes are reachable in open spaces
  • Roughly defining a geofence area

Download miles radius catchment data

Draw a postcode catchment area manually


How can you create a drawn catchment area using postcodes?
It’s possible to manually create a catchment area by drawing a shape on a map to extract postcode data.

When should you use travel time catchment areas?
If you already know your postcode data catchment area and can define it on a map, there’s a free simple tool that can pull all postcodes from this area.


  • Targeting an advertising campaign to an existing customer base
  • Selecting a new office when you already have location preferences
Download postcodes within an area or Learn more about postcode maps and tools



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