Population · Japan
Japan population forecast
Population, total
Model run: Sep 28, 2026 · TimesFM 2.5
12 months forecast · 2026
122.7M
Median forecast · p10-p90: 121.7M to 122.9M
24 months forecast · 2027
122.3M
Median forecast · p10-p90: 120.9M to 122.8M
36 months forecast · 2028
121.6M
Median forecast · p10-p90: 119.6M to 122.4M
Latest observed: 123.4M · 2025
Choose a horizon
The median and range update together.
History & forecast
White: observed history. Blue: forecast median. Shaded: p10-p90 model range.
Display-only line. World Bank data is annual: the forecasts are the yearly points marked on the chart. The monthly line between them is a straight-line interpolation for display, not a monthly forecast.
All values in People
Model validation
| Horizon | Tests | Model errorModel | No-change errorNo change | Band coverageCoverage |
|---|---|---|---|---|
| 12 months | 5 | 0.18M | 0.58M | 100.0% |
| 24 months | 4 | 0.29M | 1.15M | 100.0% |
| 36 months | 3 | 0.37M | 1.74M | 100.0% |
In these tests the model had lower average error than a no-change forecast at all 3 horizons. Rolling backtests of this model on the latest revised history; overlapping forecast errors are not independent. The p10-p90 band is a model range, not a calibrated guarantee. Methodology · Forecast audit
Evidence & context
Source data
Source & observed data
| Year | Value | Change |
|---|---|---|
| 2025 | 123.4M | −0.49% |
| 2024 | 124.0M | −0.43% |
| 2023 | 124.5M | −0.49% |
| 2022 | 125.1M | −0.44% |
| 2021 | 125.7M | −0.46% |
| 2020 | 126.3M | −0.29% |
| 2019 | 126.6M | −0.14% |
| 2018 | 126.8M | −0.13% |
| 2017 | 127.0M | −0.08% |
| 2016 | 127.1M | −0.05% |
Sources & limits
Source: World Bank, World Development Indicators · SP.POP.TOTL. Methodology · Forecast audit
Historical context
Outside the model
What could change this forecast?
A small, dated reading list. TimesFM sees the data series, not these stories. This context is not a trading signal.
No recent item selected for this series. We would rather leave this quiet than fill it with a weak match.
Selected for relevance, not a claim of causation. Source dates stay visible. Original reporting remains with its publisher.