UK population projection for 2049 falls to 72.4 million

GAD's technical bulletin puts the UK's projected population in mid-2049 at 72.4 million under the ONS 2024-based national population projectionsGOV, compared with 75.9 million under the previous 2022-based setGOV. The Government Actuary's Department highlights lower fertility and migration assumptions, alongside broadly unchanged life expectancy projections, in its technical bulletin for pension and public-finance work.

The principal projection puts the population on a path from an estimated 69.3 million in mid-2024GOV to a peak of 72.5 million in mid-2054GOV, followed by a declineGOV. Net international migration is the only expected source of population growthGOV: births are projected to remain below deaths over the projection periodGOV. These are assumption-based projections, which GAD cautions should not be treated as predictions or forecasts.

The population is also projected to age. The number of people aged 85 and over doubles from 1.8 million in mid-2024 to 3.6 million in mid-2049GOV, while the working-age population increases by around 5%. Over that period, the old-age-dependency ratio rises from 280 to 329 people of pensionable age for every 1,000 people of working ageGOV.

For advisers comparing demographic assumptions, the long-term net international migration assumption is now 230,000 a yearGOV, down from 340,000GOV. The assumed total fertility rate is 1.38 children per woman by 2029GOV, rising to 1.42 by 2049GOV; the previous long-term assumption was 1.45GOV. GAD says the new assumptions imply fewer births, less net migration and fewer deaths than the previous projections.

The long-term mortality improvement rate remains 1.1% a year for ages 90 and under. At older ages it tapers linearly to zero at age 110, with no improvement assumed from that age onwardsGOV. Improvement rates converge to the long-term rate in 2049 and remain constant thereafter. GAD describes the resulting cohort life expectancy projections as very similar to the 2022-based set. Cohort projections allow for future mortality improvements; period life expectancy uses mortality rates in the year concerned without subsequent improvements.

GAD says the assumptions underlying the most recent projections are usually used in public service pension scheme valuations, accounts and factors, as well as some other schemes and policy work such as the State Pension age review. Fertility and migration assumptions also inform National Insurance Fund projections of contribution income and benefit spending. Consistent assumptions support projections of public finances across government.

ONS has published 13 variants alongside the principal projectionGOV to illustrate alternative fertility, mortality and migration assumptions. They indicate uncertainty but are not upper or lower limits on future demographic outcomes. The findings are set out in GAD's 2024-based population projections technical bulletin, drawing on the ONS national population projections published in April 2026.