What is international migration and how do we estimate it?

Patterns of migration are always changing, and over recent decades the pace of change has increased.

International travel has become increasingly affordable, and new technology supports some people to work remotely and more flexibly. In addition, world events like the coronavirus (COVID-19) pandemic and international conflicts have led to rapid changes in where and how people move across the world.

In the UK, changes to our migration system, such as those following Brexit, have also affected who moves in and out of the country, and why.

All of this affects the way we think about and count migration, and our methods need to adapt to this range of societal changes. This article explains what our long-term international migration statistics mean, what they do not show us, and how this is changing.

Our long-term international migration figures count two groups of people: those moving to the UK (immigrants), and those leaving the UK to live abroad (emigrants).

We consider someone to be a long-term migrant if they are coming to live in the UK (or moving to another country) for at least one year, in line with the United Nations definition.

It might seem as though counting these flows into and out of the UK would be easy, as most people have their travel documents checked at the border. However, the process of identifying long-term migrants is not that straightforward. Most arrivals at UK borders are not people coming to live here long-term. The vast majority are British nationals returning from trips abroad, tourists and other visitors or short-term migrants.

Identifying long-term migrants from all these travellers can be difficult: not everyone needs a visa to move to the UK, some may arrive using one passport and leave using another, and others’ plans may change once they are in the country, to name a few complications we need to consider.

As well as migrants moving to the UK, we also need to consider current residents who move abroad. We minus these from the immigration figures, to produce our headline ‘net migration’ number, which tells us if the population has risen or declined through migration in a given year.

When we account for those that emigrated out of the UK in the year to December 2024, the net migration figure was 345,000 people. This means that the UK population had grown by 345,000 people through migration in that year.

In 2024, the UK population grew by 345,000 people through migration

Immigration, emigration and net migration, by non-EU+, EU+ and British nationality, year to December 2024

Download the data for migration by non-EU+, EU+ and British nationality (XLSX, 17KB)

In recent decades, net migration has been positive, and rising, peaking at 944,000 people in the year to March 2023. This was driven largely by immigration from outside EU+ countries.

How a person travels to the UK, where they travel from and their purpose for staying in the country all affect how they might be counted in our statistics.

We used to estimate migration using a survey that questioned a sample of people at UK airports, seaports and the Channel Tunnel about their intentions, called the International Passenger Survey.

However, this had limitations, as we could only base our estimates on what people told us about their plans. We have been working to reduce our reliance on this source, and utilise newly available administrative data from the Home Office and Department for Work and Pensions to create more accurate estimates, based on people’s actual behaviour.

Bringing these different sources together is complicated, and these methods are still in development. We have been using Home Office data on visa and asylum applications to count migrants from outside EU+ countries in recent years.

More recently, we have published new research explaining our new approach to capturing migration of EU+ citizens and British nationals.

You can find out more in Understanding international migration statistics.

Throughout this article, we have included examples of possible migrant journeys to demonstrate how different people are counted in our data, and to show the complex real-life situations that our methods need to account for. All names and scenarios used are fictional.

Migration to and from non-EU+ countries

The Home Office routinely collects data on visa applications, asylum claims and other humanitarian migration routes. We use these as a starting point to estimate the migration patterns of people from countries outside the EU+ area.

While these are important information sources, they do not show us the whole picture regarding migration on their own. The record of how many long-term visa applications are made and granted does not directly reflect the number of individuals coming to live in the UK long-term. For example, not everyone issued a visa travels on it. We also cannot tell from this information alone when a person leaves the country.

Example: Migration for study

Use the arrows to follow Amy's journey

Others might apply for a long-term visa after arriving in the country, or enter as a short-term traveller, or without documentation at all.

As a result, it takes time, both to identify as many migrants in our statistics as we can, and to confirm whether they will stay long-term.

Example: Seeking asylum

Use the arrows to follow Milad's story

In certain cases, the UK offers humanitarian protection via specific visas, such as those issued through the Ukraine scheme or Afghan resettlement scheme.

We group people who move to the UK on humanitarian visas separately to those seeking asylum, as the terms of their stay are slightly different, but all those in the UK for at least 12 months still contribute to our long-term international migration estimates.

Migration to and from EU+ countries

Since 1 January 2021 (when the Brexit transition period ended), citizens of EU+ countries no longer automatically have freedom of movement to live and work in the UK long-term. Now, they can either qualify for EU settled status (EUSS), which is open to EU+ citizens who were already resident in the UK, or they must apply for an existing visa route.

For those who travel via a visa route, we are beginning to use the same Home Office Borders and Immigration (HOBI) data and methods that we do for non-EU+ nationals.

By comparing the start and end dates of an individual’s visa with their first arrival to and last departure from the UK, we can estimate the number of people granted long-term visas who end up travelling on them and remaining in the country for a year or more.

Example: Migrating for work

Use the arrows to follow Eline's story

However, people with EU settled status, or Irish nationals, do not need a visa to move to the UK. Therefore, to estimate migration of these groups, we need more information.

For those with EU settled status, we use the same travel data from the Home Office to identify those who are newly emigrating out or migrating into the UK.

Without information from visa applications, we only have information on people’s travel into and out of the country. This is not enough information, as most entrances to or exits from the UK are not a person making a long-term move. Many people with settled status may have been resident in the UK for a long time, and they are appearing in Home Office figures due to short-term travel.

Because of this, we use extra assumptions to identify the cases where a person with settled status is moving into or out of the country long-term. This involves a range of steps, including looking at the cumulative amount of time they spend in and out of the country in a given year. We also need to make assumptions about behaviour where data on a person’s travel into and out of the country is incomplete.

You can find our more in Implementing new methods for estimating the international migration of EU+ nationals, progress update: November 2025.

Example: Migrating with EU settled status

Use the right hand arrows to follow Louis' story

Estimating migration of Irish nationals adds further complication, as not only do they not require a visa to live and work in the UK, they are also often not recorded in Home Office travel data, as there is an open border between Northern Ireland and the Republic of Ireland.

In this case, we use additional data from the Department for Work and Pensions known as the Registration and Population Interaction Database (RAPID).

This allows us to identify Irish nationals who pay taxes or claim benefits in the UK using their Irish documentation. This helps us to produce better estimates of Irish nationals moving into and out of the UK long-term in a given period.

Migration of British nationals

When British nationals migrate in and out of the country, they still contribute to population change, but they do not require a visa or other permissions to do so.

This makes identifying long-term migration of British nationals a particular challenge. Millions of British citizens enter and leave the country on a regular basis, and most of these journeys are short-term holidays or business trips.

Similarly to our approach in estimating long-term migration among Irish nationals, to produce the best estimates we can of British nationals moving into or out of the country long-term, we utilise the Department for Work and Pensions (DWP)’s RAPID dataset, which captures interactions with the UK taxes and benefits system.

This dataset is not designed to count migration. But, using information on when people start or stop paying UK taxes, claiming benefits or interacting with the education system, we can estimate arrivals to and exits from the UK.

Example: Retiring abroad

Use the arrows to follow Peggy’s story

As with estimates based on Home Office data, we need to carry out extra analysis to make our figures as accurate as possible. There are many reasons that a person may not appear in the taxes and benefits system in a given year, without them necessarily being out of the country.

This might include someone transitioning from a job where they are on a payroll to more casual, cash-in-hand labour, meaning they are no longer active in the tax system. Some residents may neither work nor claim any benefits, again leading to them being missing from DWP’s data.

We have found that older adults in particular, (aged 45 to 65 years) may interact with these systems less than other age groups. This is because they are more likely than other age groups to have the means to live without working or claiming benefits.

Children, too, can be harder to estimate, as if a parent is not claiming child benefit on their behalf, they will not appear in the data.

We therefore have to make further adjustments to our estimates to account for these differences in coverage for certain groups.

While this method is generally reliable for creating migration figures for some British nationals, the data we use are not updated when a person naturalises to become a British national.

To estimate migration journeys among these British nationals, we need to use extra data sources to estimate the number of people who may have naturalised to become British nationals, and then subsequently migrated after naturalising. You can learn more in our Implementing new methods for estimating the international migration of British nationals, progress update: November 2025.

Emigrating as a naturalised British national

Use the arrows to follow Sameer’s story

We have been measuring long-term international migration in and out of the UK for over 60 years.

From the late 1960s to the early 1980s, net migration was consistently negative, meaning in most years, more people moved out of the country than moved into it.

In the late 1990s, this trend reversed, and net migration began to rise.

It then fell sharply during the coronavirus (COVID-19) pandemic in 2020, when significant travel restrictions were in place throughout the world. In the same year, the UK’s transition period for leaving the EU ended, and a new immigration system was introduced.

Since 2020, we have seen a sharp increase in non-EU+ net migration, while the number of EU+ nationals moving to the UK is smaller than the number of those leaving the country.

Net migration has been rising in recent decades

Immigration, emigration and net migration, UK, 1964 - 2024

Download the data for UK immigration, emigration and net migration (XLSX, 21KB)

Brexit

Brexit refers to the UK’s withdrawal from the European Union (EU), which officially took place on 31 January 2020. This affected the terms by which many people were able to live and work in the UK, as freedom of movement between EU countries no longer applied.

British National

For the purposes of our estimates, we assume a British national is anyone who has a National Insurance Number (NINo) and who is not included in the Migrant Worker Scan (MWS).

The MWS contains information on overseas nationals who have registered for, and are allocated, a NINo. A full description of this process is provided in Department for Work and Pensions (DWP)’s NINo allocations methodology.  

We also count people who are included in the MWS that have been resident in the UK for many years as British nationals, because they are likely to have become British citizens.

Users should note that this definition is statistical and may differ from legal definitions of nationality.

For full information on the definition used in our estimates, please refer to: Implementing new methods for estimating the international migration of British nationals, progress update: November 2025 article.

Emigration

Emigration refers to a person leaving the UK to live elsewhere for 12 months or more.

EU+

In our estimates, we refer to EU+ to group citizens of all European Union countries, plus Norway, Iceland, Liechtenstein and Switzerland.

We use this grouping, because citizens of these additional countries share similar rights to those of EU countries despite not being full members of the EU.

EU Settled Status

EU settled status is a status available to EU+ citizens, allowing them to live and work in the UK for an indefinite period, after the UK left the EU and freedom of movement was rescinded.

Immigration

Immigration refers to people moving from another country to live in the UK for 12 months or more.

Net migration

Net migration is the difference between the number of people coming to live in the UK (immigration) and the number of people leaving to live elsewhere (emigration). When more people are coming to the UK than leaving, net migration is above zero and so adds to the UK population.

Non-EU+

Non-EU+ refers to the rest of the world, including the rest of Europe, not included in the EU+ category. British nationals are excluded from these numbers.