You’ve probably heard of a billion. You definitely know what a trillion is, mostly because that’s the scale of national debts and the market caps of companies like Apple or Microsoft. But then you hit a wall. Once you get past the familiar territory of "illions," the numbers start to feel like fake math. They sound like something a kid makes up on a playground. A sextillion is one of those numbers that feels imaginary until you realize it’s actually the backbone of how we measure the stars, the ocean, and even the data sitting on your phone right now.
It's huge. Like, incomprehensibly huge.
If you’re looking for a quick definition, a sextillion is a 1 followed by 21 zeros. In scientific notation, we write it as $10^{21}$. But seeing a bunch of zeros on a screen doesn't actually tell you anything about the scale. To understand what a sextillion is, you have to stop thinking about math and start thinking about the physical world.
The Math Behind a Sextillion (and Why It Confuses Everyone)
Numbers this big are tricky because the world hasn't agreed on what to call them. Honestly, it’s a bit of a mess. In the United States and the UK (since the 1970s), we use the "short scale." In this system, every new "-illion" name is 1,000 times larger than the last one. So, a billion is a thousand millions, a trillion is a thousand billions, and so on. In this system, a sextillion is $1,000^7$.
But if you go to France or Germany, they often use the "long scale." Over there, a "billion" is what we call a trillion. In those places, a sextillion is a 1 followed by 36 zeros ($10^{36}$). For the sake of your sanity and this article, we are sticking to the short scale used in global finance and modern science.
A sextillion is a billion trillion.
Think about that for a second. Take everything that makes a trillion enormous—the years it would take to count it, the sheer volume of stuff—and then imagine having a billion of those. It’s a number that exists almost exclusively in the realms of astronomy, chemistry, and high-level data science. You won't find it in your bank account, unfortunately.
Real-World Examples of a Sextillion
Abstract math is boring. To really "get" this number, we need to look at things we can touch, even if they're very small.
The Sand on Every Beach
People love to use this as a metaphor for "uncountable," but researchers at the University of Hawaii actually tried to calculate it. They estimated that there are roughly seven quintillion, five hundred quadrillion grains of sand on Earth. That is a massive amount of grit in your shoes. But guess what? That isn't even a sextillion. You would need about 130 Earths' worth of beaches to reach just one sextillion grains of sand.
The Stars in the Sky
When you look up at night, you're seeing a tiny fraction of what's out there. Astronomers estimate that the observable universe contains about 200 sextillion stars. Some estimates from teams like those working with the Hubble and James Webb telescopes suggest the number could be even higher, perhaps reaching into the septillions if we account for galaxies we can't fully resolve yet. But 200 sextillion is the "safe" expert bet. It means there are more stars in the sky than there are grains of sand on every beach on our planet.
Drops of Water in the Ocean
The total volume of Earth's oceans is roughly 1.3 billion cubic kilometers. If you break that down into individual drops of water—the kind of drop you’d see from a pipette—you get close to our magic number. There are roughly 26 sextillion drops of water in all the oceans on Earth combined.
Measuring the Earth
If you wanted to weigh the planet, you'd need a very big scale and a lot of patience. Earth's mass is approximately 5,972 sextillion metric tons. When you're dealing with the weight of planets, the numbers get so heavy that "trillions" just don't cut it anymore.
Sextillions in Technology and Data
We are living in the "Zettabyte Era." A zettabyte is a unit of digital information storage. To give you an idea of the scale, one zettabyte is equal to one sextillion bytes.
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In 2020, the total amount of data created, captured, copied, and consumed globally was about 64 zettabytes. By 2025, that's expected to climb past 180 zettabytes. That is 180 sextillion bytes of data. Every "like" on Instagram, every weird TikTok dance, every frantic late-night Google search for "how to fix a leaky faucet" adds to this sextillion-scale mountain of data.
We are moving so fast that we’ve actually had to invent new prefixes. In 2022, the International Bureau of Weights and Measures introduced "ronna" and "quetta" because "zetta" (which represents the sextillion range) wasn't enough to describe the world's upcoming data needs. A ronnabyte is $10^{27}$. We are literally outgrowing the sextillion.
How to Visualize a Sextillion (If You Can)
Visualizing large numbers is a biological weakness for humans. Our brains evolved to count things we could eat or things that could eat us. Usually, that meant numbers under 100.
If you tried to count to a sextillion out loud, saying one number every second, you would not finish in your lifetime. You wouldn't finish in your grandkids' lifetime. In fact, the universe would probably end before you got there. It would take you roughly 31 quadrillion years to count to a sextillion. For context, the universe is only about 13.8 billion years old.
You’d have to restart the universe millions of times over just to finish your count.
Why This Number Matters for the Future
It’s easy to dismiss this as "just more zeros," but understanding sextillions is actually pretty vital for the next century of human progress.
- Carbon Capture: When scientists talk about removing $CO_2$ from the atmosphere, they are dealing with molecules on a sextillion scale. To move the needle on climate change, we have to process sextillions of molecules.
- Nanotechnology: We are building machines at the molecular level. A single gram of copper contains about 10 sextillion atoms. If we want to build nanobots, we have to understand the logistics of managing materials at this density.
- Cryptographic Security: Your bank account is safe because of numbers like this. Encryption keys use massive prime numbers. The number of possible combinations in a 256-bit AES encryption (the gold standard) is 115 quattuorvigintillion—a number so much larger than a sextillion that it makes a sextillion look like a rounding error. But the sextillion range is where the "brute force" attempts to break into systems often live.
Common Misconceptions
People often mix up sextillions with septillions or quintillions. It's an easy mistake.
- The Name: No, it’s not a "sexy" number. The prefix "sext-" comes from the Latin for six. In the short scale, a sextillion is the sixth power of a thousand (after a million, which is the first).
- Money: There is no such thing as a sextillionaire. Even if you combined all the wealth on Earth—every house, every gold bar, every stock share, and every dollar bill—you wouldn't even come close to a quadrillion, let alone a sextillion. The total global wealth is currently estimated at around $450 trillion to $500 trillion. You’d need to multiply the entire world's wealth by two million to hit a single sextillion.
- Physical Space: A sextillion pennies would not fit on Earth. They would create a sphere that would swallow our planet and extend far out into space.
Actionable Takeaways for Dealing with Massive Scales
When you encounter numbers like "sextillion" in news reports or scientific papers, don't let your brain glaze over. Use these tricks to keep things in perspective.
Check the Zeros
Always verify if the writer is using the short scale or the long scale. If it's a scientific paper, they'll usually use scientific notation ($10^{21}$), which is the only way to stay truly accurate.
Use the "Grains of Sand" Rule
If a number is bigger than 7 quintillion, it's bigger than all the sand on Earth. If it's in the sextillions, you're talking about the scale of stars or atoms.
Watch the Prefixes
In the metric system, "Zetta" is the prefix for sextillion. If you see "Zettameters" or "Zettagrams," you're looking at a sextillion of those units.
Focus on the Ratios
Instead of trying to imagine the whole number, look at the ratio. If a company says they've processed a sextillion bits of data, compare that to the zettabyte scale of the entire internet. It helps you see if the claim is actually impressive or just marketing fluff.
The sextillion is the bridge between the world we see and the world we can only calculate. It's the point where human intuition fails and pure mathematics takes over. Whether you're thinking about the atoms in your coffee cup or the stars in a distant galaxy, you're operating in the realm of the sextillion. It is the number that reminds us just how small we are—and how incredibly vast the universe is.