Yamanashi山梨県
Kai 甲斐市
Data last updated:
Kai, Yamanashi, Japan has a population of 75,507 (2025 national census). IPSS projections estimate 73,758 by 2030 and 65,709 by 2050 (a decrease of about 12.8% from 2020), with the share of residents aged 65+ rising from 26.3% in 2020 to 37.6%.Sources: Japan Census (Statistics Bureau), IPSS Regional Population Projections (2023)
2025
(Census)
75,507
2030
(Projection)
73,758
▼ -2.1%
2040
(Projection)
70,031
▼ -7.0%
2050
(Projection)
65,709
▼ -12.8%
Change vs. 2020 census
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Other municipalities in Yamanashi (山梨県)
Data Sources
- Portal Site of Official Statistics of Japan (e-Stat)（https://www.e-stat.go.jp/）
- National Institute of Population and Social Security Research (IPSS), Regional Population Projections (2023 ed.)
* This service uses the e-Stat API but its content is not guaranteed by the Japanese government.
Kai Population Table (1980–2050)
Population by year: national census results (restated to current municipal boundaries) and IPSS (2023) projections based on the 2020 census.
| Year | Population | vs 2020 | Type |
|---|---|---|---|
| 1980 | 45,337 | ▼ -39.8% | Census |
| 1985 | 54,291 | ▼ -27.9% | Census |
| 1990 | 60,765 | ▼ -19.3% | Census |
| 1995 | 66,628 | ▼ -11.5% | Census |
| 2000 | 71,706 | ▼ -4.8% | Census |
| 2005 | 74,062 | ▼ -1.7% | Census |
| 2010 | 73,807 | ▼ -2.0% | Census |
| 2015 | 74,386 | ▼ -1.2% | Census |
| 2020 | 75,313 | — | Census |
| 2025 | 75,507 | ▲ +0.3% | Census |
| 2030 | 73,758 | ▼ -2.1% | Projection |
| 2035 | 72,049 | ▼ -4.3% | Projection |
| 2040 | 70,031 | ▼ -7.0% | Projection |
| 2045 | 67,921 | ▼ -9.8% | Projection |
| 2050 | 65,709 | ▼ -12.8% | Projection |
About Kai
Overview
Kai (甲斐市) is a municipality in Yamanashi, Japan, with a population of 75,507 as of 2025.
Population Projection of Kai
According to projections by Japan's National Institute of Population and Social Security Research (IPSS), Kai's population is expected to reach 73,758 by 2030 (-2.1%), 70,031 by 2040 (-7.0%), and 65,709 by 2050 (-12.8%). A modest population change is expected.
Aging Rate of Kai
The aging rate (percentage of residents aged 65 and over) is 26.3% as of 2020 and is projected to rise to 37.6% by 2050. The aging rate will remain below the most severe Japanese averages.
National Comparison
Kai's demographic trajectory is similar to the national average.
National and Prefectural Rank
- Population decline rate: Ranked #1545 out of 1903 municipalities nationwide.
- Aging rate in 2050: Ranked #1430 out of 1903 nationwide.
- Population size: Ranked #515 out of 1917 nationwide.
- Related: National rankings / All municipalities in Yamanashi
Earnings in Yamanashi (山梨県): Average salary in Yamanashi (山梨県) by age, gender and company sizejpsalary / MHLW Basic Survey on Wage Structure