Update: This article was last updated on 21st May 2026 to reflect the accuracy and up-to-date information on the page.
Why Large Numbers Matter More Than You Think
Have you ever asked yourself, “What comes after a trillion?” You’re in good company. As economies balloon into the trillions, as astronomers count stars measured in sextillions, and as data scientists track information in quintillions of bytes, understanding large numbers has quietly become a life skill.
After you wrap your head around a trillion (1,000,000,000,000), it’s natural to wonder: what’s after a trillion? What comes after a quadrillion? What comes after quintillion, sextillion, septillion, and decillion? And where do mythical-sounding numbers like a googol and googolplex fit in?
This guide answers every one of those questions, clearly, completely, and in the correct order, with real-world context, a full reference table, and the fun facts that make large numbers genuinely fascinating.
Quick Answer: What Comes After Trillion?
The number that comes right after a trillion is a quadrillion (10¹⁵, or 1 followed by 15 zeros). After quadrillion, the sequence continues:
- Trillion → Quadrillion → Quintillion → Sextillion → Septillion → Octillion → Nonillion → Decillion → …and beyond
Each name in this chain represents a number 1,000 times larger than the one before it. This is called the short-scale system, used in the United States, the United Kingdom, and most English-speaking countries.
Key takeaway: After a trillion, what’s next is always a “new -illion.” Every time you add three more zeros to a number, it earns a new name.
Complete Table: Large Numbers from Million to Googolplex
| Number Name | Power of 10 | Written Out | zeros |
|---|---|---|---|
| Million | 106 | 1,000,000 | |
| Billion | 109 | 1,000,000,000 | |
| Trillion | 1012 | 1,000,000,000,000 | |
| Quadrillion | 1015 | 1,000,000,000,000,000 | |
| Quintillion | 1018 | 1,000,000,000,000,000,000 | |
| Sextillion | 1021 | 1 followed by 21 zeros | |
| Septillion | 1024 | 1 followed by 24 zeros | |
| Octillion | 1027 | 1 followed by 27 zeros | |
| Nonillion | 1030 | 1 followed by 30 zeros | |
| Decillion | 1033 | 1 followed by 33 zeros | |
| Undecillion | 1036 | 1 followed by 36 zeros | |
| Duodecillion | 1039 | 1 followed by 39 zeros | |
| Tredecillion | 1042 | 1 followed by 42 zeros | |
| Vigintillion | 1063 | 1 followed by 63 zeros | |
| Centillion | 10303 | 1 followed by 303 zeros | |
| Googol | 10100 | 1 followed by 100 zeros | |
| Googolplex | 10(10100) | Unimaginably large |
Note: All values above follow the short-scale (US/UK) naming convention.
What Comes After Each Number — Step by Step
What Comes After Billion?
After a billion (10⁹) comes a trillion (10¹²). A trillion is a thousand billion, written as 1,000,000,000,000. This is the scale at which national budgets and tech company valuations are often measured.
What Comes After Trillion? (What’s After Trillion)
The answer to “what is after trillion” is quadrillion (10¹⁵) — 1 followed by 15 zeros. Numbers between trillion and quadrillion still carry the word “trillion” (e.g., two trillion, 500 trillion). Only when three more zeros are added does the number receive a brand-new name.
What Comes After Quadrillion?
After quadrillion comes quintillion (10¹⁸) — 1 followed by 18 zeros. One quintillion equals a thousand quadrillions, a million trillions, or a billion billions. This is roughly the scale at which modern data storage volumes are discussed.
What Comes After Quintillion?
After quintillion comes sextillion (10²¹). Sextillion is a 1 followed by 21 zeros. Astronomers use numbers in this range when counting the estimated number of stars in the observable universe (~10²³).
What Comes After Sextillion?
After sextillion comes septillion (10²⁴). Avogadro’s number — the count of atoms in one mole of a substance (approximately 6.022 × 10²³) — sits in septillion territory, making this a staple number in chemistry.
What Comes After Septillion?
After septillion comes octillion (10²⁷), then nonillion (10³⁰).
What Comes After Decillion?
After decillion (10³³) comes undecillion (10³⁶). The pattern continues using Latin prefixes: undecillion, duodecillion, tredecillion, quattuordecillion, and so on, all the way up to vigintillion (10⁶³) and centillion (10³⁰³). After centillion, the naming structure continues but is rarely used in practice.
Short Scale vs. Long Scale: Why Different Countries Count Differently
One important thing to know is that not all countries use the same naming system. The two main systems are:
- Short scale (used in the US, UK, Brazil, and most English-speaking countries): A new name is given every 3 zeros (every 1,000×).
- Long scale (used in parts of Europe and Latin America): A new name is given every 6 zeros (every 1,000,000×).
This means that in the short scale, a “billion” is 10⁹ (a thousand million), while in the long scale, a “billion” is 10¹² (a million million) — which is what Americans call a trillion. This difference has caused genuine confusion in international finance, journalism, and science.
| Number Name | Short Scale (US/UK) | Long Scale (Europe) |
|---|---|---|
| Billion | 109 (1,000 million) | 1012 (1 million million) |
| Trillion | 1012 (1,000 billion) | 1018 (1 million billion) |
| Quadrillion | 1015 | 1024 |
| Quintillion | 1018 | 1030 |
For this guide, all numbers follow the short scale — the standard in the United States and modern UK usage.
What Is a Googol and a Googolplex?
What Is a Googol?
A googol is 10¹⁰⁰ — a 1 followed by exactly 100 zeros. The term was coined in 1920 by American mathematician Edward Kasner, who asked his nine-year-old nephew, Milton Sirotta, to invent a name for the number.
(Yes, Google the search engine took its name from this word — misspelled!)To put a googol in context: the estimated total number of atoms in the observable universe is only around 10⁸⁰ — far less than a googol. So a googol is larger than anything you could ever physically count.
What Is a Googolplex?
A googolplex is 10^(googol) — that is, a 1 followed by a googol of zeros. This number is so astronomically large that even if you used every atom in the observable universe as an ink particle, you still could not write it out. It comfortably eclipses not just what comes after decillion, but every physically meaningful quantity in the known universe.
Fun Facts About Large Numbers
- Counting to a trillion: If you counted one number per second, non-stop, it would take approximately 31,709 years to reach one trillion. That’s longer than all of recorded human history.
- Counting to a quadrillion: At one number per second, reaching a quadrillion would take over 31 million years.
- A googol vs. the universe: A googol (10¹⁰⁰) is vastly larger than the estimated number of atoms in the observable universe (~10⁸⁰). Yet googol is still dwarfed by googolplex.
- Skewes’ Number: Mathematician Stanley Skewes introduced a number (~10^(10^34)) that was once called the largest number ever used in a serious mathematical proof (1933).
- Graham’s Number: This is so incomprehensibly large that conventional mathematical notation cannot express it. It currently holds the informal record for the largest number ever used in a mathematical proof, dwarfing even googolplex.
- Centillion: A centillion (10³⁰³) is already beyond anything in physics — yet it’s still technically a named number smaller than a googol.
Real-World Applications of Large Numbers
Large numbers aren’t just abstract math puzzles. They show up in economics, science, technology, and nature. Here’s where each scale becomes relevant in the real world:
| Number | Field | Example |
|---|---|---|
| Trillion | Economics | US national debt (~$34 trillion in 2024) |
| Quadrillion | Finance | Global derivatives market (~$1 quadrillion) |
| Quintillion | Data | ~2.5 quintillion bytes of data created daily |
| Sextillion | Astronomy | Estimated number of stars in the observable universe (~1022) |
| Septillion | Chemistry | Avogadro's number (~6.02 × 1023 atoms/mole) |
| Octillion | Physics | Estimated grains of sand on Earth (~7.5 × 1018) |
| Decillion+ | Cryptography | Possible combinations in advanced encryption keys |
As our world generates more data, explores deeper into space, and grapples with larger financial systems, numbers that once seemed purely theoretical are becoming everyday language. Understanding what comes after quintillion or what comes after sextillion is increasingly relevant for students, scientists, and professionals alike.
How to Remember the Order of Large Numbers
The naming pattern is logical once you see the system. Each new name is built from Latin prefixes that indicate position in the sequence:
- Quad- (4) → Quadrillion
- Quint- (5) → Quintillion
- Sex- (6) → Sextillion
- Sept- (7) → Septillion
- Oct- (8) → Octillion
- Non- (9) → Nonillion
- Dec- (10) → Decillion
A useful mnemonic: “Quite Safely, Some Older Numbers Don’t Ever Cause Unfair Grief” — the first letters stand for Quadrillion, Quintillion, Sextillion, Septillion, Octillion, Nonillion, Decillion, Undecillion, Centillion.
Pro tip: Each step multiplies the previous number by 1,000. So quintillion = 1,000 × quadrillion = 1,000,000 × trillion. The zero count always increases by 3.
Conclusion
So, what comes after trillion? Quadrillion. And after quadrillion? Quintillion. Then sextillion, septillion, octillion, nonillion, and decillion — each representing a number 1,000 times larger than the last.
These numbers aren’t just mathematical curiosities. From the trillions in global economics to the sextillions of stars in the sky, from quintillions of bytes of data to the septillion-scale Avogadro’s number in chemistry — large numbers define the universe at every scale.
Whether you’re a student wondering what’s after a trillion for the first time, or a curious adult exploring the upper limits of human counting, one thing is certain: the number line goes on forever. There will always be something bigger. And that’s what makes mathematics endlessly exciting.
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Frequently Asked Questions (FAQ)
Q: What comes after a trillion?
Ans: The number after a trillion is a quadrillion (10¹⁵). Numbers between trillion and quadrillion are still named with the word trillion (e.g., 500 trillion), but the next official new name in the sequence is quadrillion.
Q: What’s after quadrillion?
Ans: After quadrillion comes quintillion (10¹⁸). After that: sextillion → septillion → octillion → nonillion → decillion.
Q: What comes after quintillion?
Ans: After quintillion (10¹⁸) comes sextillion (10²¹). It’s 1 followed by 21 zeros.
Q: What comes after sextillion?
Ans: After sextillion comes septillion (10²⁴). Septillion is 1 followed by 24 zeros and is notable because Avogadro’s number (~6.022 × 10²³) falls in this range.
Q: What comes after septillion?
Ans: After septillion comes octillion (10²⁷), then nonillion (10³⁰), then decillion (10³³).
Q: What comes after decillion?
Ans: After decillion (10³³) comes undecillion (10³⁶). The pattern continues: duodecillion, tredecillion, and so on up through vigintillion (10⁶³), centillion (10³⁰³), and eventually numbers like a googol (10¹⁰⁰).
Q: Is “zillion” a real number?
Ans: No. “Zillion” is informal slang meaning “a very large, uncountable amount.” It has no fixed mathematical value.
Q: What’s the biggest named number?
Ans: The largest named numbers include Graham’s Number and Rayo’s Number. However, Graham’s Number is so enormous it cannot be expressed in standard notation — it makes a googolplex look microscopic by comparison.
