According to recent estimates, the 23 wards that make up the city of Tokyo had an approximate 2016 population of 9,262,046. The 23 wards made up the boundaries of the historic city of Tokyo, which was officially dissolved in 1943 when it merged with the prefecture. Today, Tokyo extends way beyond the original city boundaries, and is one of the largest urban sprawls in the world, which doesn't make it easy to explain exactly how many people live in Tokyo.

Expansion of Tokyo

The Tokyo prefecture, into which Tokyo city was merged, was home to 13,047,446 people in 2010. But the story doesn't end there -- the Tokyo urban area extends beyond even the prefecture's boundaries.

According to a 2016 estimate of Tokyo's population, the metropolis is now home to 13.5 million people, or 9,262,046 in all of the 23 wards. This does not include the population of the metro area, which we will get into in a moment.

The population of Tokyo may be a bit hard to understand because of the way the figures are laid out. The 23 wards claim a population of 9.2 million, but the metropolis has a population that exceeds 13 million. The greater Tokyo metropolitan area, which is spread over 3 prefectures, is much larger and has a population that is estimated to be over 36 million. That means the greater Tokyo area is home to 25% of Japan's population, and it's the most populous metropolitan area in the world. The metropolitan area is so large, in fact, that it is 1.5 times larger than the world's next largest metropolitan area, Seoul.

By any measure, Tokyo is the largest city in Japan. Its 23 wards are almost three times as large as Yokohama, Japan's second city, which has around 3.7 million residents.

City Size and Population Density

The surface area of the city metropolis comes to approximately 2,187.66 km2 (844.66 square miles). However, the city expands outwards to approximately 13,572 km2 (5,240 square miles). Quite the impressive sprawl. Now, to find the rough population density of the Tokyo area, we combine the total population with the available space for the residents, which comes to 6,224.66 people living per square kilometer (16,121.8 residents per square mile).

Tokyo Population History

Tokyo has always been Japan's largest city, and one of the mightiest cities in Asia, if not the world. It used to be known as Edo, and grew from a small village to become, in the 1720s, the first city in Asia with a population of more than 1 million people. Renamed Tokyo in 1868, the city continued to grow rapidly. By 1900, its population had passed 2 million for the first time, and by the start of the 1940s, the wider metropolitan area was home to more than 7 million people.

World War II saw the only major population decline in the city's history (although there have been other smaller declines over the years.) Tokyo's population halved in just five years, and when Japan surrendered in 1945, its population was just 3.5 million. Gradual attrition accounted for much of the decline, although the massive Allied air raids also took a staggering toll – at least 100,000 were killed in the US Air Force firebombing of Tokyo on March 9 1945, and around a million were estimated to have been left homeless.

The population rapidly grew again after the war, perhaps indicating that many of its residents had temporarily left the city. It took less than a decade for the city to recover to its pre-war population levels, and in 1956, Tokyo's population passed 8 million for the first time. Since then, growth has been steady, rather than spectacular, and although Tokyo's economy has (like Japan's) under-performed in recent years, its population continues to slowly rise.

The latest census data, used above, is from 2010. There is no firm data on the population of Tokyo in 2016, so the figures listed here are estimates based on the city's growth rate and preliminary 2015 census figures.

Tokyo Demographics

Tokyo is a major commuter city. That means that many of the people in the city at any one time don't actually live in the city itself; they commute in each day for work. In 2015, the Tokyo Metropolitan Government estimated the nighttime and daytime population of the city, finding that although the city's population was around 15.576 million in the daytime, this decreased to 13.159 million in the middle of the night. That means that, every day, approximately 2,400,000 people commute into Tokyo.

When it comes to working age people, the labor force is divided as follows: Clerical, Technical and Management (42.3%), Sales and Services (26.2%), Manufacturing and Transport (17.7%) and Agriculture, Forestry and Fisheries (0.4%).

Tokyo is, by most measures, the richest city in the world. Its total GDP in 2007 was $1.9 billion; that's over $300 million higher than the next richest city, New York. When adjusted for Purchasing Power Parity (PPP) the difference between Tokyo and New York narrows : in 2005 Tokyo had a PPP GDP of $1.617 billion, compared to $1.403 for New York.

The age breakdown of Tokyo's population is, as you would expect, skewed toward working age. The most recent official demographics for Tokyo were released in 2010, and they show that 68.2% of Tokyo residents are aged 15-64. Befitting a country with one of the world's longest life expectancies, there is also a high proportion of retired people in Tokyo: 20.4% of people were aged 65 or over. The remaining 11.4% of residents are children aged 0-14.

Life expectancy in Tokyo aligns with the national average of 78.8 years. Men in Tokyo can expect to live for 79.59 years and women for 86.35 years.

Tokyo Population Growth

Japan as a country is expected to rapidly decline in population thanks to little immigration, a rapidly aging population and a very low fertility rate. Japan is today the oldest country in the world, and Tokyo is no exception to the trends the country as a whole is following.

A recent study by the Tokyo Metropolitan Government, which included a group of academics and city officials, estimated the population of Tokyo in 2100. The group estimates that Tokyo's population will be just 7.13 million, compared to 13.16 million as of the 2010 census. They also predicted the city will peak at 13.35 million in 2020 before a relentless downslide. Meanwhile, Japan's population as a whole will decline by over 61% by 2100.

Meanwhile, the Japan Times forecasted that the entire population of the Prefecture of Tokyo, which is the central jurisdiction of the metropolitan region, will be cut in half between 2010 and 2100.

This means that Tokyo's population is expected to halve in the next 90 years, and by 2100, 3.27 million of the 7.13 million residents in the city will be over the age of 65. The working population of the country, which is largely concentrated in Tokyo, will age, and Tokyo's place as an international city will be at risk.