Tokyo's 23 wards have roughly 2.61 million more people in their daytime population than in their resident population. Yokohama's daytime population is about 282,000 smaller than its resident population, while Kawasaki's is about 196,000 smaller. These differences reveal how the capital region combines destinations for work and education with places where commuters live.
In 2020, the daytime-to-nighttime population ratio was 126.8 in Tokyo's 23 wards, 92.5 in Yokohama and 87.3 in Kawasaki. Adding Chiba, Saitama and Sagamihara shows why describing every city around Tokyo simply as a bedroom community misses meaningful differences.
This article compares Tokyo's 23 wards and five neighboring cities using the same 2020 reference year from Japan's System of Social and Demographic Statistics. It is not a ranking of every municipality in Greater Tokyo, and the Tokyo figures refer to the 23 wards, not Tokyo Metropolis as a whole.
What daytime and nighttime population actually mean
Nighttime population means the population that usually lives in an area. It is not a count of people walking around at night.
Daytime population adjusts that resident population for people commuting into and out of the area for work or education. It is different from station passenger counts or daily footfall that includes tourists and shoppers.
Daytime-to-nighttime population ratio = daytime population / resident population × 100
A ratio above 100 indicates that commuting inflows exceed outflows. Below 100, the reverse applies. Tokyo's ratio of 126.8 means a daytime population of roughly 127 people for every 100 residents. Definition from the Statistics Bureau of Japan
Chiba is close to 100; Kawasaki stands at 87.3
| Area | Resident population | Daytime population | Daytime minus resident population | Ratio |
|---|---|---|---|---|
| Tokyo's 23 wards | 9,733,276 | 12,346,348 | +2,613,072 | 126.8 |
| Chiba City | 974,951 | 956,669 | −18,282 | 98.1 |
| Saitama City | 1,324,025 | 1,229,480 | −94,545 | 92.9 |
| Yokohama | 3,777,491 | 3,495,975 | −281,516 | 92.5 |
| Sagamihara | 725,493 | 645,219 | −80,274 | 88.9 |
| Kawasaki | 1,538,262 | 1,342,397 | −195,865 | 87.3 |
Source: System of Social and Demographic Statistics, population and households, 2020. Ratios are the published values; differences are calculated from the population figures. The five neighboring cities' daytime populations also match the comparison table in Chiba City's tourism policy report.
Two contrasts matter. Tokyo's 23 wards are the only area in this comparison substantially above 100. Meanwhile, the five surrounding cities span a range from 98.1 to 87.3. Their access to Tokyo does not make them identical: local employment and educational destinations coexist with residential areas on different scales.
Tokyo's 23 wards accommodate a net daytime increase of 2.61 million
The wards' resident population is about 9.73 million, compared with a daytime population of 12.35 million. Tokyo is not only a large place to live; it also receives a substantial net inflow of workers and students from outside the wards.
The business districts of Marunouchi and Otemachi, hubs such as Shinjuku and Shibuya, and concentrations of universities and other schools are connected by an extensive rail network. These destinations help explain the capital's role as a center of work and education. The aggregate figures do not, however, identify how much of the net inflow is attributable to any individual station or employer.
The 2.61 million figure is a net balance, not the total number arriving. It also includes movements involving places outside the five neighboring cities in our table. It should not be treated as the number of commuters supplied by those five cities alone.
Chiba combines a Tokyo commuting role with its own regional-center functions
Chiba City comes closest to a ratio of 100 among the five neighboring cities. Its resident population of about 975,000 compares with a daytime population of about 957,000, a net difference of roughly 18,000.
Chiba combines prefectural government functions, the commercial and business district around Chiba Station, and centers such as Makuhari New City. Some residents travel toward Tokyo, while people from other municipalities travel into Chiba. Its role as a regional center overlaps with its position in Tokyo's commuting area.
A ratio of 98.1 does not mean that 98.1% of residents work inside the city. Large inflows and outflows can still produce a ratio close to 100 when they nearly balance. This measure is not a local employment-retention rate.
Yokohama and Saitama have similar ratios but different population gaps
Yokohama's ratio of 92.5 and Saitama's 92.9 differ by just 0.4 points. Yet Yokohama's net daytime reduction is about 282,000 people, compared with roughly 95,000 in Saitama. Similar ratios translate into different headcounts because Yokohama has a much larger resident population.
Yokohama has employment centers around Yokohama Station, Minato Mirai and Kannai. Saitama has Omiya's transport and commercial functions and Urawa's administrative functions. Both cities have significant local destinations for work. Their ratios also reflect the size of their residential populations and the balance of commuting across city boundaries.
Ratios help compare the relative scale of that balance; headcounts show its absolute size. Looking at both avoids assuming that Yokohama is overwhelmingly more residential simply because its net population difference is larger.
Kawasaki combines major industry with a strong residential role
Kawasaki's ratio of 87.3 is the lowest of these six areas. Its daytime population is about 1.34 million, roughly 196,000 fewer than its resident population.
Kawasaki has coastal industrial concentrations and research and development facilities, alongside residential districts with access to Tokyo and Yokohama. Transport hubs such as Musashi-Kosugi and residential neighborhoods along northern rail corridors help explain why an industrial city can also have a substantial residential role in a wider commuting region.
The ratio shows that outward commuting for work and education exceeds inward commuting at the city level. It does not establish that local businesses are weak, wages are low or quality of life is poor. Nor can the net difference of 196,000 be read as the number commuting to Tokyo: destination-specific data would be needed for that.
Sagamihara's ratio of 88.9 is also below 100, but its destinations and transport connections differ from Kawasaki's. Similar ratios do not mean identical commuting patterns.
For choosing a home, consider the home–work connection behind the ratio
The comparison reveals both Tokyo's large net commuting inflow and differences among its neighboring cities. Chiba's inflows and outflows are relatively close in net terms. Yokohama and Saitama combine their own urban centers with extensive residential roles. Kawasaki and Sagamihara show larger net outward balances relative to their resident populations in this comparison.
For an individual household, the practical questions are which rail route serves the workplace, how many transfers are needed, and whether there are employment options nearby. A citywide ratio cannot replace those questions. Neighborhoods and stations within the same city can have very different travel connections.
The cities around Tokyo are not interchangeable bedroom communities. Comparing both population totals and ratios shows a connected metropolitan area in which residential districts coexist with distinct centers of employment, government and commerce.
Data and related reading
The source is e-Stat's System of Social and Demographic Statistics, population and households, table ID 0000020101. The areas are Tokyo's special wards, Yokohama, Kawasaki, Saitama City, Chiba City and Sagamihara. All figures use 2020. The indicators are total population (A1101), daytime population (A6107) and the daytime-to-nighttime population ratio (A6108). A6108 is a ratio, not a population count.
These figures do not measure footfall in 2026. Published tables for the same census year can differ according to their treatment of unknown responses and other tabulation choices; this article consistently uses the series in the System of Social and Demographic Statistics.