You’ve probably heard it a thousand times: Tokyo is the biggest city on the planet. For decades, that was the absolute, undisputed truth. If you looked at a map or a Guinness World Records book, Japan’s neon-soaked capital sat comfortably at the top with nearly 38 million people.
But honestly? Things are getting weird.
Depending on who you ask—or more importantly, how they define "city"—the answer to what is the largest city by population in the world has actually changed. If we are talking about strictly administrative boundaries, you get one answer. If you're talking about "urban agglomerations" (the giant, sprawling carpets of concrete that ignore borders), you get a completely different story.
As of 2026, the crown is slipping from Tokyo’s head.
The New King of the Jungle: Jakarta vs. Tokyo
For a long time, Tokyo was the titan. But the United Nations and various demographic researchers, including the team at World Population Review, have started pointing toward a massive shift in Southeast Asia.
Jakarta, Indonesia, has basically exploded.
When you look at the Greater Jakarta area—often called Jabodetabek—the numbers are staggering. We are looking at a population hovering around 41.9 million people. To put that in perspective, that is more people than the entire population of Canada squeezed into a single metropolitan region.
Tokyo, meanwhile, is actually shrinking. Sorta. Japan is facing a massive demographic "graying" effect. The birth rate is low, and the government is literally paying people to move out of the city to revitalize rural towns. Because of this, Tokyo’s metropolitan population has dipped to roughly 33.4 million. Still massive, sure, but it's no longer the undisputed heavyweight champion.
Why the rankings are so confusing
You might see some lists still putting Tokyo at #1. Why? Because some statisticians only count the "Metropolitan Area" while others count the "Urban Area."
- City Proper: The literal legal boundary (Tokyo’s 23 wards). This is only about 9 million people.
- Metropolitan Area: The city plus the suburbs that commute in.
- Urban Agglomeration: The continuous built-up area. This is where Jakarta takes the lead.
The Rapid Rise of Dhaka and Delhi
If you think Jakarta is growing fast, keep an eye on Dhaka, Bangladesh. It is currently the second most populous urban area in the world, hitting about 36.6 million residents.
It's dense. Like, incredibly dense.
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While Tokyo feels organized and Tokyo-ites have mastered the art of the "silent commute," Dhaka is the opposite. It’s loud, it’s vibrant, and it’s growing at a rate of over 3% every year. At this pace, the UN projects Dhaka could become the absolute largest city by population in the world by the middle of the century.
Then there’s Delhi. India’s capital is a behemoth. With roughly 35.5 million people in the National Capital Region (NCR), it is a powerhouse of migration. People move there from all over India for work, creating a melting pot that is both culturally rich and environmentally stressed.
What Is It Actually Like to Live There?
Living in the world's largest cities isn't just about the numbers; it's about the daily grind. You've got to deal with things that people in small towns can't even imagine.
The Commute is Life
In Jakarta, the traffic is legendary. Before the new MRT lines opened up, it wasn't uncommon for people to spend four hours a day in "macet" (traffic jams). In Tokyo, the "Pushers" (Oshiya) on the subway are real—staff members whose job is literally to shove people into the trains so the doors can close.
The Space Crunch
Ever heard of a "coffin home"? While that’s more of a Hong Kong phenomenon, Tokyo has popularized the "9-square-meter" apartment. It’s basically a bed, a desk, and a wet-room-style bathroom. People live there because they want to be near the action.
The Food (The Best Part)
The upside? The food is incredible. In a city of 40 million, you can find anything. Whether it’s 24-hour ramen in Shinjuku or spicy Nasi Goreng from a street cart in Jakarta at 2 AM, these cities never actually sleep.
The Top 10 Heavyweights (2026 Estimates)
Since we can't do a perfect table without sounding like a robot, let's just look at the heavy hitters as they stand today based on urban agglomeration data:
- Jakarta, Indonesia: ~41.9 Million (The New Leader)
- Dhaka, Bangladesh: ~36.6 Million (Fastest Growing)
- Tokyo, Japan: ~33.4 Million (The Former Champ)
- Delhi, India: ~35.5 Million (Massive Regional Sprawl)
- Shanghai, China: ~31 Million (The Global Hub)
- Guangzhou, China: ~27.6 Million
- Cairo, Egypt: ~25.6 Million (Africa’s Brightest Star)
- Manila, Philippines: ~24.7 Million
- Mumbai, India: ~22.5 Million
- Seoul, South Korea: ~22.5 Million
Why This Matters for the Future
The shift from Tokyo to cities like Jakarta and Dhaka isn't just a fun fact for trivia night. It represents a massive shift in global power and economics.
The "Global South" is where the world is moving.
These megacities are the front lines of climate change, too. Jakarta is actually sinking—so much so that Indonesia is building a whole new capital city, Nusantara, on the island of Borneo to take the pressure off.
What most people get wrong about "Size"
People often confuse "most populous" with "largest land area." New York City, for instance, has a massive land footprint but only about 8 million people in the city proper (around 20 million in the metro). It doesn't even crack the top 10 anymore.
Size in the 21st century is measured in souls, not square miles.
Actionable Insights for Travelers and Business
If you’re planning to visit or do business in the largest city by population in the world, here are a few reality checks:
- Don't trust the maps: In cities like Jakarta or Manila, "two miles away" could mean a 10-minute walk or a 90-minute car ride. Always use local transit apps like Gojek or Grab.
- Book the "Quiet" Neighborhoods: If you’re visiting Tokyo, stay in neighborhoods like Setagaya or Kichijoji. You get the "megacity" vibe without the Shinjuku headache.
- Respect the Infrastructure: These cities are under immense strain. Be a "low-impact" tourist. Use public transit, manage your waste, and don't be "that person" blocking the flow of 40 million people trying to get to work.
- Watch the Air Quality: Use apps like IQAir before heading out in Delhi or Dhaka. On bad days, you’ll want a high-quality mask.
The world is urbanizing faster than we can track. While Tokyo defined the 20th-century megacity, the future belongs to the sprawling, chaotic, and incredibly energetic hubs of South and Southeast Asia.
Next Steps for You
To truly grasp the scale of these places, you should check out the latest UN World Urbanization Prospects report. It’s the gold standard for how these populations are measured. If you're planning a trip to any of these giants, start by looking into the "New Capital" projects in Indonesia or Egypt—it'll give you a fascinating look at how governments are trying to solve the problem of having too many people in one place.