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Postcode Facts

Interesting facts and information about postcodes

Updated 20 Oct 2020

What is the biggest postcode area in the UK?

The biggest postcode area is IV, also known as Inverness. It is made up of 52 postcode districts for post towns.

How big is a postcode area?

There are 124 postcode areas in the United Kingdom. The average size of an area is 776 square miles and the average population is 533,000.

Which postcode has the longest addresses?

The UK postcode consists of five to seven alphanumeric characters which define four different levels of geographic unit. CH5 3QW has the longest addresses in terms of numbers of elements.

What is a numeric postcode?

Each postcode area is divided into a number of districts which are represented by the numerical portion of each part of the postcode. These numbers range from 0 to 99.

Can you send a letter with just a postcode?

Perhaps. Large user organisations have a postcodes entirely to themselves, however it's unlikely your letter will reach the intended recipient when it arrives at the destination.

Including the postcode in a letter is essential to ensure it is delivered to the correct address. A full address should include a premise identifier and post town at the very least.

Read our good addressing guide to ensure your mail is correctly addressed.

How often are postcodes updated?

Postcodes are updated daily and available on Royal Mail’s Postcode Address File.

Can a postcode be changed?

Royal Mail does not make changes to postcodes unless it is absolutely necessary and there is an operational reason. Residents can request changes; however, there has to be enough evidence that all the affected are in favour.

You can find out more in Royal Mail’s Code of Practice.

How many UK postcodes are there?

There are roughly 1.7 million postcodes in the UK.

How many premises are in a postcode?

Each postcode covers an average of about 15 properties. However, this is not a definitive number, where postcodes can hold up to 100.