You're looking at your bank account and—okay, let’s be real. None of us are seeing trillions there. But we see the word everywhere else. National debts, the number of cells in the human body, or the distance to a far-off star. We’ve all got a handle on millions. Billions feel big, but manageable. Trillions? That’s where things start to get fuzzy.
So, what number comes after trillions?
The short answer is the quadrillion. But honestly, knowing the name is just the tip of the iceberg because the way we name these numbers changes depending on where you live on the planet. It’s a mess of "short scales" and "long scales" that has confused mathematicians for centuries.
The Math Behind the Quadrillion
Once you hit 999,999,999,999,999, you are one digit away from the jump. Add one more, and you’ve arrived at $1,000,000,000,000,000$. That is a one followed by fifteen zeros.
If you spent one dollar every single second, it would take you about 31,709 years to reach a trillion. To reach a quadrillion? You’d be clicking that stopwatch for over 31 million years. It’s a scale that the human brain isn't really wired to visualize. We basically just see "a lot" and "even more."
Most of the English-speaking world, including the U.S. and the UK, uses the short scale. In this system, every new "named" number is 1,000 times larger than the previous one. It’s consistent. It’s clean. But it hasn't always been the standard.
Why the British Changed Their Minds
For a long time, if you asked someone in London what comes after a trillion, they might have said a "trilliard" or just jumped straight to a quintillion. They used the long scale, where a billion was actually a million million ($10^{12}$), not a thousand million ($10^{9}$).
This created a massive headache for international trade and science. Imagine a mid-century diplomat trying to discuss a billion-dollar loan when one side thinks that’s a thousand million and the other thinks it's a million million. That’s a 999-billion-dollar misunderstanding.
Eventually, in 1974, Harold Wilson’s government officially pulled the plug on the long scale for UK government stats. They aligned with the U.S. system to keep things simple. Most people followed suit, but if you travel to parts of Continental Europe or Latin America, the "long scale" is still very much alive. In those places, the number after a billón isn't a trillón—it's a mil millones.
The Ladder to Infinity
Once you pass the quadrillion, the naming convention follows a pretty predictable Latin-prefix pattern. It’s actually kinda satisfying once you see the rhythm of it.
- Quintillion: 18 zeros. This is roughly the number of grains of sand on all the Earth’s beaches combined (estimated at about 7.5 quintillion).
- Sextillion: 21 zeros.
- Septillion: 24 zeros. The Earth weighs about six septillion kilograms.
- Octillion: 27 zeros.
- Nonillion: 30 zeros.
- Decillion: 33 zeros.
By the time you get to a googol (not the search engine, but the number), you’re looking at a 1 followed by 100 zeros. There aren't even that many atoms in the observable universe. Most estimates put the atom count at around $10^{80}$. A googol is essentially a "useless" number for physical counting, but it’s a fun playground for theoretical mathematicians like those at the Mathematical Association of America.
Real World Quadrillions
We actually use these numbers more than you’d think. Especially in technology.
Modern supercomputers are the main reason we talk about quadrillions. We measure their speed in "FLOPS" (Floating-point Operations Per Second). In 2008, the IBM Roadrunner was the first to hit the "petaflop" milestone. A petaflop is one quadrillion floating-point operations per second.
Today, we’ve already moved past that. We are firmly in the era of exascale computing. An exaflop is a quintillion operations per second. The Frontier supercomputer at Oak Ridge National Laboratory was the first to officially crack this barrier.
Does it ever end?
Technically, no. You can keep adding zeros until the sun burns out. But the names eventually run out of common Latin roots. You get into things like the vigintillion (63 zeros) or the centillion (303 zeros in the short scale).
At that point, even the most hardcore scientists stop using names. They just use scientific notation. It’s much easier to write $10^{45}$ than it is to remember that it's called a quattuordecillion.
How to Handle These Numbers Without Getting Confused
If you’re writing a paper, coding a simulation, or just trying to sound smart at a dinner party, here is how you should actually handle the question of what number comes after trillions.
First, clarify the scale. If you are in the U.S., UK, or Australia, you are safe with the short scale (Quadrillion). If you are writing for a French or German audience, use scientific notation ($10^{15}$) to avoid any linguistic traps.
Second, use analogies. Nobody knows what a quadrillion looks like. If you tell someone that a quadrillion seconds is about 32 million years, they’ll actually feel the weight of the number.
Third, remember the prefixes.
- Tera = Trillion
- Peta = Quadrillion
- Exa = Quintillion
- Zetta = Sextillion
These are the same prefixes you see on hard drives. We used to have megabyte drives, then gigabytes, then terabytes. Within the next decade, prosumer gear will likely start hitting petabyte levels. You'll be holding a quadrillion bytes of data in the palm of your hand.
Actionable Steps for Large Number Literacy
To truly master the scale of these numbers, stop trying to count zeros and start looking at the exponents.
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- Switch to Scientific Notation: For anything larger than a trillion, write it as $1.0 \times 10^x$. It prevents "zero-blur" where your eyes just skip over the end of the number.
- Verify the Region: If you are dealing with international finance, always double-check if the "billion" or "trillion" in the contract refers to the $10^9/10^{12}$ or $10^{12}/10^{18}$ scale. It sounds pedantic until you realize the difference is a factor of a million.
- Use Data Visualization: Tools like "The Scale of the Universe" or various "billionaire visualization" sites help ground these abstract terms in physical reality.
The jump from trillion to quadrillion represents more than just three extra zeros. It represents the point where human intuition completely fails and we have to rely entirely on the cold, hard logic of mathematics. Whether we’re measuring the operations of an AI or the distance between galaxies, the quadrillion is our first real step into the truly vast.