Japan released the preliminary tabulation of the 2025 Population Census in May 2026. For the first time we can compare actual 2020→2025 change against the projection published by the National Institute of Population and Social Security Research (IPSS). This guide explains what the numbers mean, where decline is concentrating, and how to use the data on this site.
What the 2025 preliminary tabulation contains
The preliminary tabulation provides total population (by sex) and the number of households for every municipality, as of 1 October 2025. Age-breakdown figures are not part of the preliminary release; they arrive with the Basic Tabulation scheduled for September 2026. So 'aging' figures on this site remain based on the 2020 Census until then.
Because municipal boundaries can change, the 2020 figures are re-tabulated to 2025 boundaries before the change rate is computed. That is why the 2020→2025 change rate may differ slightly from a naive comparison of the two raw census counts.
Where decline is concentrating
Decline is overwhelmingly a non-metropolitan story. Small towns and villages — especially in mountainous and remote areas — continue to lose population fastest, while a handful of suburban municipalities around Tokyo, Nagoya and Fukuoka still grow. You can see the spread in the actual 2020→2025 decline ranking and the longer-horizon 2050 projection ranking.
A useful, site-original lens is the gap between projection and actual: some municipalities are declining faster than the IPSS projected, others slower. Reasons range from disaster recovery to new transit access or housing supply.
Projection vs actual: how to read the gap
Both the census (actual) and the IPSS projection are referenced to 1 October, but the projection is anchored to the 2020 base. A positive gap (actual above projection) means the area held up better than the model expected; a negative gap means it declined faster. Treat large positive gaps in tiny municipalities with caution — small populations swing on small absolute changes.
This guide explains how to read official statistics and does not constitute legal, tax or investment advice. For decisions on purchasing property in Japan, consult a qualified professional.
How to use this on the site
Every municipality page shows the 2025 preliminary population alongside the 2020 figure and the 2050 projection, so you can see past, present and projected trajectory at a glance. Prefecture pages let you sort all municipalities by 2020→2050 change.
Explore the data
FAQ
- Is the 2025 Census data final?
- No. These are preliminary figures (total population and households). The final Basic Tabulation, including age structure, is scheduled for September 2026 and may differ.
- Why does the 2020→2025 change rate differ from subtracting the two census counts?
- The 2020 population is re-tabulated to 2025 municipal boundaries before computing the change, so boundary changes do not distort the rate.
- Does population decline mean property is cheaper?
- Not directly. Decline affects long-run demand and services, but local price depends on many factors. This site provides data, not valuations; consult a professional.
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