# 1,000,000,000,000

**1,000,000,000,000** is the natural number equal to \( 10^{12} \), a one followed by twelve zeros. In the short scale used in [American English](https://www.edgepedia.org/american-english) and, since 1974, in official British usage, it is called one trillion; in the long scale still used in much of continental Europe, the same quantity is called one billion.<sup>[1](https://www.ibiblio.org/units/large.html)</sup><sup> • </sup><sup>[2](https://commonslibrary.parliament.uk/research-briefings/sn04440/)</sup> In the [International System of Units](https://www.edgepedia.org/international-system-of-units) (SI) the number appears as the multiplier of the prefix tera (symbol T), as in one terawatt or one terabyte.<sup>[3](https://www.bipm.org/en/measurement-units/si-prefixes)</sup>

| Key fact | Detail |
|---|---|
| Value | \( 10^{12} \), a one followed by twelve zeros<sup>[1](https://www.ibiblio.org/units/large.html)</sup> |
| Short-scale name | One trillion, a thousand billion<sup>[1](https://www.ibiblio.org/units/large.html)</sup> |
| Long-scale name | One billion, a million million<sup>[1](https://www.ibiblio.org/units/large.html)</sup> |
| SI prefix | Tera (T), \( 10^{12} = (10^{3})^{4} \), adopted by the 11th CGPM in 1960<sup>[3](https://www.bipm.org/en/measurement-units/si-prefixes)</sup><sup> • </sup><sup>[4](https://www.bipm.org/en/committees/cg/cgpm/11-1960/resolution-12)</sup> |
| Binary counterpart | Tebi (Ti), \( 2^{40} = 1\,099\,511\,627\,776 \), about 9.95 percent larger<sup>[5](https://pml.nist.gov/cuu/Units/binary.html)</sup> |
| Word origin | English "trillion", 1680s, from French *trillion*, from Italian *trilione*<sup>[6](https://www.etymonline.com/word/trillion)</sup> |
| Scale of the quantity | About 21 countries have a GDP above one trillion dollars; \( 10^{12} \) dollars divided among 8.2 billion people is almost $122 each<sup>[7](https://apnews.com/article/52a7b96a31287a7de11615d6bdeba4ae)</sup> |

## Names and the two scales

English names for large numbers are built from Latin prefixes with the ending -illion, so trillion takes tri- (three). In the American or short scale, the name coined from the Latin number n applies to \( 10^{3n+3} \), which makes trillion \( 10^{12} \). In the system traditional in many European countries, the same name applies to \( 10^{6n} \), which makes trillion \( 10^{18} \) and gives the value \( 10^{12} \) the name billion.<sup>[1](https://www.ibiblio.org/units/large.html)</sup> The Oxford Learner's Dictionary records the short-scale sense "one million million; 1 000 000 000 000" as the current definition and labels "one million million million" as old-fashioned [British English](https://www.edgepedia.org/british-english).<sup>[8](https://www.oxfordlearnersdictionaries.com/us/definition/english/trillion)</sup>

**Historical shift.** The French mathematician Nicolas Chuquet (1445 to 1488) apparently coined the words byllion and tryllion for \( 10^{12} \) and \( 10^{18} \), establishing what became the long scale, while French mathematicians of the 1600s used billion and trillion for \( 10^{9} \) and \( 10^{12} \).<sup>[1](https://www.ibiblio.org/units/large.html)</sup> The English word trillion is recorded from the 1680s, from French *trillion*, from Italian *trilione*.<sup>[6](https://www.etymonline.com/word/trillion)</sup> In 1974 the government of Prime Minister Harold Wilson confirmed that official British publications would use billion to mean a thousand million, in conformity with international usage, so British trillion moved to the short-scale value \( 10^{12} \).<sup>[2](https://commonslibrary.parliament.uk/research-briefings/sn04440/)</sup>

## The SI prefix tera

The [SI prefix](https://www.edgepedia.org/si-prefix) for \( 10^{12} \) is tera, with symbol T, listed as \( 10^{12} = (10^{3})^{4} \) in the official prefix table.<sup>[3](https://www.bipm.org/en/measurement-units/si-prefixes)</sup><sup> • </sup><sup>[9](https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-4-two-classes-si-units-and-si-prefixes)</sup> It was adopted into the SI at its creation by the 11th [General Conference on Weights and Measures](https://www.edgepedia.org/general-conference-on-weights-and-measures) (CGPM) in 1960, resolution 12, which listed 1 000 000 000 000 = \( 10^{12} \) as tera.<sup>[4](https://www.bipm.org/en/committees/cg/cgpm/11-1960/resolution-12)</sup> IUPAC's Gold Book defines tera as the SI prefix for \( 10^{12} \) with symbol T.<sup>[10](https://goldbook.iupac.org/terms/view/T06271/plain)</sup> NIST's [metric prefix](https://www.edgepedia.org/metric-prefix) chart pairs tera with the English word trillion.<sup>[11](https://www.nist.gov/pml/owm/metric-si-prefixes)</sup>

**Usage rules.** NIST states that the SI prefixes refer strictly to powers of 10 and should not be used to indicate powers of 2; using tera to mean \( 2^{40} \) is not permitted, and the IEC binary prefix tebi (Ti) exists for that purpose.<sup>[12](https://www.nist.gov/pml/special-publication-330/sp-330-section-3)</sup> Because the names of numbers \( 10^{9} \) and larger are not uniform worldwide, NIST recommends avoiding them entirely and expressing large numbers as powers of 10, noting that in many countries one billion means \( 1 \times 10^{12} \), not \( 1 \times 10^{9} \) as in the United States.<sup>[13](https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-7-rules-and-style-conventions-expressing-values)</sup>

## Binary counterpart

In computing, \( 2^{40} \) bytes is written with the binary prefix tebi (Ti), giving one tebibyte (TiB) = 1 099 511 627 776 bytes, while one terabyte (TB) = \( 10^{12} \) = 1 000 000 000 000 bytes. The binary prefixes were approved by the IEC in December 1998 as Amendment 2 to IEC 60027-2, developed by IEC Technical Committee 25 with support from the CIPM and IEEE; each name keeps the first two letters of the corresponding SI prefix and adds "bi" for binary.<sup>[5](https://pml.nist.gov/cuu/Units/binary.html)</sup> This distinction is why a drive marketed in terabytes shows a smaller capacity when an operating system reports it in tebibytes.<sup>[5](https://pml.nist.gov/cuu/Units/binary.html)</sup>

## Sense of scale

The AP news service, in coverage of a trillion-dollar net worth, gives several concrete renderings of \( 10^{12} \) dollars: divided among the nearly 8.2 billion people on Earth it is almost $122 per person; at a median U.S. house price of about $403,200 it buys nearly 2.5 million homes; and at a national average gasoline price of nearly $4.11 per gallon it buys more than 243 billion gallons of fuel.<sup>[7](https://apnews.com/article/52a7b96a31287a7de11615d6bdeba4ae)</sup> In energy units, one trillion watt hours is one terawatt hour (TWh); the United Kingdom's total electricity consumption in 2023 was 317 TWh.<sup>[2](https://commonslibrary.parliament.uk/research-briefings/sn04440/)</sup>

## References

1. [Names for Large Numbers, Russ Rowlett, University of North Carolina](https://www.ibiblio.org/units/large.html)
2. [What is a billion? And other large numbers, House of Commons Library](https://commonslibrary.parliament.uk/research-briefings/sn04440/)
3. [SI prefixes, BIPM](https://www.bipm.org/en/measurement-units/si-prefixes)
4. [CGPM Resolution 12 (1960), BIPM](https://www.bipm.org/en/committees/cg/cgpm/11-1960/resolution-12)
5. [Definitions of the SI units: The binary prefixes, NIST](https://pml.nist.gov/cuu/Units/binary.html)
6. [Trillion, Online Etymology Dictionary](https://www.etymonline.com/word/trillion)
7. [What Elon Musk's trillion means in real terms, AP News](https://apnews.com/article/52a7b96a31287a7de11615d6bdeba4ae)
8. [Trillion, Oxford Advanced Learner's Dictionary](https://www.oxfordlearnersdictionaries.com/us/definition/english/trillion)
9. [NIST Guide to the SI, Chapter 4: The Two Classes of SI Units and the SI Prefixes](https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-4-two-classes-si-units-and-si-prefixes)
10. [Tera, IUPAC Gold Book](https://goldbook.iupac.org/terms/view/T06271/plain)
11. [Metric (SI) Prefixes, NIST](https://www.nist.gov/pml/owm/metric-si-prefixes)
12. [SP 330 - Section 3, NIST](https://www.nist.gov/pml/special-publication-330/sp-330-section-3)
13. [NIST Guide to the SI, Chapter 7: Rules and Style Conventions for Expressing Values of Quantities](https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-7-rules-and-style-conventions-expressing-values)

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*Topic: Encyclopedia › Physical world and mathematics › Mathematics and statistics › Numbers and algebra › Arithmetic and number systems › Integer sequences and partitions › Special and named integers › Named large numbers and number naming systems*

*Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 15, 2026 · Edited: Oct 15, 2026 · Last review: Oct 15, 2026*

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