Guidance

2022-based population projections: a GAD technical bulletin

Published 3 July 2025

Introduction

The 2022-based national population projections (NPPs) from the Office for National Statistics (ONS) provide an indication of future developments of the UK and its constituent countries’ population size and age structure. The NPPs were published in January 2025. This bulletin summarises some of the key findings at the UK level and focuses on the mortality assumptions and results which are most relevant to GAD’s work.

Overall results

ONS’s statistical bulletin summarises the main results, including:

• a population increase - the UK population is projected to increase from an estimated 67.6 million in mid-2022 to 72.5 million in mid-2032 and 76.6 million in mid-2047
• an ageing population - the number of people aged 85 years and over is projected to almost double in the next 25 years, from 1.7 million in 2022 to 3.3 million by 2047
• an increased old-age-dependency ratio - for every 1,000 people of working age, there will be 302 people of pensionable age by mid-2047, up from 278 in mid-2022
• greater population growth than previously projected - with 5.1 million more people in the UK population by mid-2045 (76.1 million), compared to the previous 2020-based projections (71.0 million)

The chart below shows the projected age structure of the UK population in mid-2022 and mid-2032 and by mid-2032 the number of:

• children is projected to decrease by 0.8 million (-6.4%), from 12.4 million to 11.6 million
• working-age people is projected to increase by 4.1 million (9.4%), from 43.2 million to 47.3 million
• people of pensionable age is projected to increase by 1.7 million (13.8%), from 12.0 million to 13.7 million.

Figure 1: Age structure of the UK population, mid-2022 and mid-2032.

Source: ONS, National population projections

Some of the underlying reasons for these changes are that over the 10 years to 2032:

• Net migration is projected to be 4.9 million. Long-term assumed net migration is 340,000 per annum, with an allowance for higher migration in the first 5 years of the projections
• 6.8 million births are projected with long-term assumed fertility rate decreasing for the 2022 projections to 1.45 children per women
• 6.8 million deaths are projected (see more detail below)

Interactive population pyramids are available on the ONS website.

Data and assumptions

ONS produces a ‘principal’ projection based on a set of long-term assumptions considered to best reflect patterns of future fertility, mortality, and net migration based on recent data. The assumptions underlying the 2022-based projections lead to an almost equal number of projected births as deaths over the ten years to 2032 (6.8 million). It is important that projections are not viewed as predictions or forecasts, but as an indication of the future based on observed demographic trends and the assumptions adopted.

The 2022-based projections have been produced using a new set of long-term demographic assumptions for fertility, mortality, and migration, which are derived from analysis of past trends and through consultation with independent academic experts. This release is based upon the 2022 mid-year estimate for the UK population and a revised back series of data from Census 2021 (for England, Wales, and Northern Ireland) and Census 2022 (for Scotland).

Mortality assumptions

To project the number of people at each age in the future, it is key to work out how long people are expected to live. Historically life expectancy in the UK has generally improved over time (albeit at a slower rate in recent years), so it is important to consider if these improvements will continue in the future.

Data from the UK mid-year population estimates and annual calendar year deaths from 1973 to 2022 are projected forwards using a mathematical model. The improvements then converge to a ‘long-term rate of improvement’ (LTR) in the 25th year of the projections (2047) and remain constant thereafter (for ages 90 and below).

A new model has been used to project mortality improvements for the 2022-based NPPs. Assumptions used in the model are based on an analysis of mortality data as well as advice from the external NPP Mortality Expert Advisory Panel. The Expert Panel advise on several areas, in particular the treatment of the mortality shock caused by COVID-19, the LTR, differences between England, Scotland, Wales and Northern Ireland, and other technical aspects of the mortality model.

In recognition that mortality improvements have been consistently lower than the previous LTR assumption (1.2% per annum) for more than 10 years, the ONS has revised down the LTR to 1.1% per annum for age 90 and under.

Further information is available on the mortality assumptions underlying the 2022-based projections. Other supporting publications include details of the methodology used, and the datasets for the national population projections.

Impact on life expectancy

Life expectancies are still projected to increase over time, but less quickly than in the 2020-based projections. This is a consequence of the slower increases in life expectancy in recent years, the impact of the COVID-19 pandemic, and the lower assumed improvements in the longer term.

The overall effect is that, compared to the 2020-based projections, cohort life expectancies (which allow for future mortality improvements) are lower for both males and females at most ages (except for older females).

	2022-based projections (years)	2020-based projections (years)	2020 vs 2022 projections (years)
At birth
Males	87.1	87.9	-0.8
Females	90.3	90.7	-0.4
At age 65
Males	20.0	20.1	-0.1
Females	22.7	22.4	+0.3

Figure 2: Sample life expectancies in 2025

Source: ONS, expectation of life, principal projection, UK

The chart below shows the principal projection of period life expectancies (which do not allow for future mortality improvements) at birth for males and females - showing changes between the 2012-based and 2022-based projections.

There is a pattern of falling projected period life expectancy with each successive round of projections, although life expectancy is still projected to increase over time. The impact of the COVID-19 pandemic on period life expectancy is clearly shown by the drop in the historical data line (dark blue) in 2020. The 2020-based projections (red) assumed a quicker return to pre-pandemic life expectancy than what actually happened – shown by the historical data (dark blue) between 2020 and 2023.

Figure 3: Principal period life expectancy at birth: changes between 2012-based and 2022-based projections, UK

Source: ONS, national population projections, mortality assumptions

Variant projections

For the 2022 NPPs, ONS has published 14 variant projections alongside the principal projection. These are based on alternative assumptions of fertility, mortality, and migration compared with the principal projection. They provide an indication of uncertainty in, and the outcomes of, alternative assumptions. Variant scenarios relating solely to life expectancy are the high life expectancy, low life expectancy and no long-term mortality improvement variants. Variants were not produced for the 2020-based interim NPPs.

In June 2025, the ONS posted a notice on its website recommending that the ‘migration category variant’ projections are used instead of the principal projection for projections for UK and England. This is due to the availability of more up to date migration data. The fertility and mortality assumptions for this variant are the same as for the principal projection.

An interactive population projection explorer produced by the ONS, helps illustrate the effect of different assumptions on the UK’s projected population up to 50 years in the future.

The key assumptions relating to the principal and variant projections are summarised in the following table:

	Low	Principal	High
Fertility (total fertility rate by mid-2047)	1.25	1.45	1.65
Mortality (improvement rate by 2047)	0.5%	1.1%	1.5%
Migration (year ending mid-2028 onwards)	120,000	340,000	525,000

Figure 4: Long-term assumptions for the 2022-based national population projections, UK

Source: ONS, variant projections

If you would like to discuss the NPPs in more detail or have any questions about the implications for our work for you, please get in touch with your usual GAD contact or email: enquiries@gad.gov.uk.