<p>Outside the IT world, 1兆 is 10^12, or 1万 x 1亿. But you won't see this use very much now.</p>

<p>Inside the IT world, (when you talk about the size of hard disk, memory, etc ...) 1兆 is 1M, which is 1024k, approximately 10^6. The might be the more common use nowadays.</p>

<p>Edit:</p>

<p><a href="https://zh.wikipedia.org/wiki/%E5%9B%BD%E9%99%85%E5%8D%95%E4%BD%8D%E5%88%B6%E8%AF%8D%E5%A4%B4" rel="noreferrer">When used in SI unit</a>, 兆 mean 10^6 in mainland China and 10^12 in Taiwan. The use in IT world actually comes from this usage, with an altered value. It is actually part of the unit, not the number.</p>

CC BY-SA 4.0
2019-11-28T11:52:17.833Z
According to Chinese (mainland) national standard, 10^6 in SI units should be 兆, and 10^12 should always be 万亿, never 兆.


http://zjj.beijing.gov.cn/wsbs/infoview.asp?ViewID=50494
10的4次方称为万，10的8次方称为亿，10的12次方称为万亿
Victor
CC BY-SA 3.0
2018-01-24T05:21:02.540Z
2018-01-24T08:17:59.003Z
2018-01-24T08:17:59.003Z
fefe
<p>In the decimal system we have</p>

<p>一 10^0, 十 10^1, 百 10^2, 千 10^3, 万 10^4</p>

<p>Remember, the power indicates the quantity of zero appears behind a single number.</p>

<p>We array these units when reading a big number, as 万千百十个 (where 个/个位 means single digit or the unit). For example, 96,128 is reading as 九万六千一百二十八.</p>

<p>A number which is bigger than (or equal to) 10^5, will be presented circularly by these units as 千百十万千百十个. For example, 75,896,128 is reading as 七千五百八十九万六千一百二十八.</p>

<p>THE KEY is, we use four digits as a <em>loop</em> for convenience, 千百十万,千百十个. We don't say 七千万五百万八十万九万, actually we omit the anterior units of 万 and hold only one to indicate.</p>

<p>万万 for 10^8 is not used today, commonly. We have 亿. And again,  346,275,896,128 is reading as 三千四百六十二亿七千五百八十九万六千一百二十八.</p>

<p><strong><em>After that is 兆, the unit you asked. So it means 10^12. Thus, there are 12 zeros behind 一兆, as 1,000,000,000,000.</em></strong></p>

<p>Here's a different way to show a number bigger than 万, and I think it may be the reason beset you and many people.</p>

<p>"十万为亿，十亿为兆，十兆为京."  亿=100,000, <strong><em>兆=1,000,000,</em></strong> 京=10,000,000.</p>

<p>Then 75,896,128 is reading as 七京五兆八亿九万六千一百二十八.</p>

<p>The chaos comes, for we don't follow <strong><em>the original rule that each digit has its own unit</em></strong>. We use four digits as loop to reach 100,000,000,000 in the economic region on daily life. With the total amount of GDP in China rising over that much, 兆 will be used as a new current unit in the mainland. And the past problems of the units will still troubled people even then.</p>

CC BY-SA 3.0
2018-01-25T03:36:00.437Z
Although I already understood how numbers are formed, all the background in these answers is interesting and may help others.  I did add emphasis to the part that actually answers part of the question.
伟思礼
CC BY-SA 3.0
2018-01-25T04:30:12.287Z
@伟思礼 I gave two answers so I emphasized the other one.
Hao FU
CC BY-SA 3.0
2018-01-25T02:24:18.613Z
2018-01-25T05:12:55.070Z
2018-01-25T05:12:55.070Z
Hao FU
<p>According to Chinese (mainland) national standard, only the <a href="https://en.wikipedia.org/wiki/Metric_prefix" rel="nofollow noreferrer">metric prefix</a> &quot;mega-&quot; (for 10<sup>6</sup>) is 兆, while a trillion (10<sup>12</sup>) should always be 万亿, never 兆.</p>
<p>e.g. 一兆字节 (or 一兆 for short) means one megabyte (1 MB), and 一兆赫 means one megahertz (1 MHz).</p>
<p><a href="http://zjj.beijing.gov.cn/wsbs/infoview.asp?ViewID=50494" rel="nofollow noreferrer">http://zjj.beijing.gov.cn/wsbs/infoview.asp?ViewID=50494</a></p>
<blockquote>
<p>10的6次方    兆   M</p>
<p>10的4次方称为万，10的8次方称为亿，10的12次方称为万亿</p>
</blockquote>
<hr />
<p>In Taiwan, most people use 兆 for 10<sup>12</sup>.</p>

CC BY-SA 4.0
2019-11-28T12:23:34.253Z
2019-11-28T12:32:51.483Z
2020-06-17T09:50:11.587Z
Victor
<p>In fact, 兆 could be million, trillion, or 10 quadrillions. In China mainland, the word is usually used to indicate million. Like the sentence "The file is 1MB" could translate to "这个文件（的大小是）一兆"（although, we usually just write "1M" or "1MB" instead of "一兆" since it's simpler）. The "兆" in "兆瓦", "兆赫", "兆帕" also means million.
But I heard in Taiwan, it usually means trillion.</p>

CC BY-SA 3.0
2018-01-25T09:12:59.590Z
2018-01-25T09:12:59.590Z
Xin
<p>Edit:</p>

<blockquote>
  <p>I might had misunderstood the question. I think the OP is askeing '兆' as '<strong>part of</strong>' a number(unit), for example <strong>兆</strong>瓦 (MW) . Not '兆' as a number itself, for example "一<strong>兆</strong>日圆" is "one <strong>trillion</strong> yen"</p>
</blockquote>

<p>~</p>

<p>The text below therefore did not answer the original question, but adding additional information on the character 兆 instead</p>

<blockquote>
  <p><a href="http://www.cantonese.sheik.co.uk/dictionary/characters/1420/" rel="nofollow noreferrer">http://www.cantonese.sheik.co.uk/dictionary/characters/1420/</a></p>
  
  <p>兆</p>
  
  <p>million million (China)</p>
  
  <p>trillion (Taiwan)</p>
</blockquote>

<p>~</p>

<blockquote>
  <p><a href="https://en.wikipedia.org/wiki/Trillion" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Trillion</a></p>
  
  <p>Trillion  (short scale) = 1,000,000,000,000; one million million; SI prefix: <strong>tera</strong>-</p>
  
  <p><strong>the current meaning</strong> in both American and British English</p>
</blockquote>

<p>~</p>

<blockquote>
  <p>Trillion (long scale) (1,000,000,000,000,000,000); one million million million; SI prefix: <strong>exa</strong>-), the <strong>former meaning</strong> in British English and current usage in many non-English-speaking countries</p>
</blockquote>

<p>Since the current meaning of 兆 (trillion) is 'one million million'(China's standard) It should be our standard. </p>

CC BY-SA 3.0
2018-01-24T06:52:05.523Z
Are you saying that CEDICT needs to be changed to also add "(old)" for million and mega?  And when you say "our," are you referring to this site, or to some Chinese-speaking country?  I have nothing against Cantonese, but I'm currently trying to acquire 普通话.  fefe and user3306356 seem to be saying it is more commonly used for "mega"
伟思礼
CC BY-SA 3.0
2018-01-24T09:43:19.240Z
兆 in 兆瓦 (MW) is 'one million' ( 瓦) . But '兆 ' itself as a number means 'trillion'
Tang Ho
CC BY-SA 3.0
2018-01-24T10:45:18.170Z
@tang ho: the controversial started in ancient time: how to interpret "兆", as 百萬, 萬億 or 億億. this wiki has info: https://zh.wikipedia.org/zh-hk/兆
水巷孑蠻
CC BY-SA 3.0
2018-01-24T06:04:46.190Z
2018-01-24T10:17:07.937Z
2018-01-24T10:17:07.937Z
Tang Ho
<p>CEDICT shows 兆 as "… / million / mega- / trillion / tera- / billion (old)".</p>

<p>Is it ever actually used numerically, or is it standard to use Arabic numbers (or M/T for prefixes) to eliminate ambiguity?</p>

<p>Speaking of ambiguity, an answer and a comment say it is more commonly used for million/mega, while another answer says trillion/tera is standard.</p>

CC BY-SA 3.0
2018-01-24T05:01:00.333Z
Mostly used for Mbps nowadays. Internet speeds are advertised like 100兆/200兆.
Mou某
CC BY-SA 3.0
2018-01-24T05:49:32.860Z
千赫 kHz, 兆赫 MHz usually written kHz,MHz
user6065
CC BY-SA 3.0
2018-01-24T06:52:16.600Z
@user3306356: That would make it "mega" while Tang Ho seems to say it should only be used for "tera"
伟思礼
CC BY-SA 3.0
2018-01-24T07:28:32.390Z
see ３rd line of answer by mentioned user, also bkrs：兆 omen; million; mega; also trillion. China = million; Japan and Taiwan = trillion (bkrs: 2) миллион; мега-
兆赫 [zhàohè] физ. - мегагерц)
user6065
CC BY-SA 3.0
2018-01-24T07:35:39.567Z
@伟思礼 tera should be 太.
Mou某
CC BY-SA 3.0
2018-01-25T03:40:11.533Z
A lot of interesting background in the answers, but the various answers still disagree on which of the two dictionary meanings is actually correct.  And if both, none of them tell how to disambiguate.  I looked around some more and found additional inconsistencies in other characters.  Of course, any web source can be wrong.  It's too broad a topic for here, but <http://Wesley.Groleau.Email/2018/01/24/numbers-dont-lie/>
伟思礼
CC BY-SA 3.0
2018-01-31T09:21:02.803Z
mainland China uses some words wrongly. so if you are talking with a mainland Chinese, it is 10 ^ 6, when talking with Taiwan/Hong Kong/Macau Chinese, it is 10 ^12.  another sample is 'row' = 行 (mainland)  = 列(Taiwan/Hong Kong/Macau), column = 列 (mainland) = 欄 (mainland / Taiwan / Hong Kong/Macau), so when you don't know if audience is mainland or not, you can just say 'M' (an alphabet).
Daniel Yang
<usage><number>
兆 as (part of) a number
# 兆 as (part of) a number

(Asked by: username_0 on 2018-01-24)

CEDICT shows 兆 as "… / million / mega- / trillion / tera- / billion (old)".

Is it ever actually used numerically, or is it standard to use Arabic numbers (or M/T for prefixes) to eliminate ambiguity?

Speaking of ambiguity, an answer and a comment say it is more commonly used for million/mega, while another answer says trillion/tera is standard.

**Tags:** usage, number
> **Comments:**
> **username_1**: Mostly used for Mbps nowadays. Internet speeds are advertised like 100兆/200兆.  
> **username_2**: 千赫 kHz, 兆赫 MHz usually written kHz,MHz  
> **username_0**: @user3306356: That would make it "mega" while Tang Ho seems to say it should only be used for "tera"  
> **username_2**: see ３rd line of answer by mentioned user, also bkrs：兆 omen; million; mega; also trillion. China = million; Japan and Taiwan = trillion (bkrs: 2) миллион; мега- 兆赫 [zhàohè] физ. - мегагерц)  
> **username_1**: @伟思礼 tera should be 太.  
> **username_0**: A lot of interesting background in the answers, but the various answers still disagree on which of the two dictionary meanings is actually correct.  And if both, none of them tell how to disambiguate.  I looked around some more and found additional inconsistencies in other characters.  Of course, any web source can be wrong.  It's too broad a topic for here, but <http://Wesley.Groleau.Email/2018/01/24/numbers-dont-lie/>  
> **username_3**: mainland China uses some words wrongly. so if you are talking with a mainland Chinese, it is 10 ^ 6, when talking with Taiwan/Hong Kong/Macau Chinese, it is 10 ^12.  another sample is 'row' = 行 (mainland)  = 列(Taiwan/Hong Kong/Macau), column = 列 (mainland) = 欄 (mainland / Taiwan / Hong Kong/Macau), so when you don't know if audience is mainland or not, you can just say 'M' (an alphabet).  

---

## 5 answers

### Answer by username_4 on 2018-01-24. Score: 7

Outside the IT world, 1兆 is 10^12, or 1万 x 1亿. But you won't see this use very much now.

Inside the IT world, (when you talk about the size of hard disk, memory, etc ...) 1兆 is 1M, which is 1024k, approximately 10^6. The might be the more common use nowadays.

Edit:

[When used in SI unit](https://zh.wikipedia.org/wiki/%E5%9B%BD%E9%99%85%E5%8D%95%E4%BD%8D%E5%88%B6%E8%AF%8D%E5%A4%B4), 兆 mean 10^6 in mainland China and 10^12 in Taiwan. The use in IT world actually comes from this usage, with an altered value. It is actually part of the unit, not the number.

> **Comments:**
> **username_5**: According to Chinese (mainland) national standard, 10^6 in SI units should be 兆, and 10^12 should always be 万亿, never 兆.   http://zjj.beijing.gov.cn/wsbs/infoview.asp?ViewID=50494 10的4次方称为万，10的8次方称为亿，10的12次方称为万亿  

---

### Answer by username_6 on 2018-01-25. Score: 1

In the decimal system we have

一 10^0, 十 10^1, 百 10^2, 千 10^3, 万 10^4

Remember, the power indicates the quantity of zero appears behind a single number.

We array these units when reading a big number, as 万千百十个 (where 个/个位 means single digit or the unit). For example, 96,128 is reading as 九万六千一百二十八.

A number which is bigger than (or equal to) 10^5, will be presented circularly by these units as 千百十万千百十个. For example, 75,896,128 is reading as 七千五百八十九万六千一百二十八.

THE KEY is, we use four digits as a *loop* for convenience, 千百十万,千百十个. We don't say 七千万五百万八十万九万, actually we omit the anterior units of 万 and hold only one to indicate.

万万 for 10^8 is not used today, commonly. We have 亿. And again, 346,275,896,128 is reading as 三千四百六十二亿七千五百八十九万六千一百二十八.

***After that is 兆, the unit you asked. So it means 10^12. Thus, there are 12 zeros behind 一兆, as 1,000,000,000,000.***

Here's a different way to show a number bigger than 万, and I think it may be the reason beset you and many people.

"十万为亿，十亿为兆，十兆为京." 亿=100,000, ***兆=1,000,000,*** 京=10,000,000.

Then 75,896,128 is reading as 七京五兆八亿九万六千一百二十八.

The chaos comes, for we don't follow ***the original rule that each digit has its own unit***. We use four digits as loop to reach 100,000,000,000 in the economic region on daily life. With the total amount of GDP in China rising over that much, 兆 will be used as a new current unit in the mainland. And the past problems of the units will still troubled people even then.

> **Comments:**
> **username_0**: Although I already understood how numbers are formed, all the background in these answers is interesting and may help others.  I did add emphasis to the part that actually answers part of the question.  
> **username_6**: @伟思礼 I gave two answers so I emphasized the other one.  

---

### Answer by username_5 on 2019-11-28. Score: 0

According to Chinese (mainland) national standard, only the [metric prefix](https://en.wikipedia.org/wiki/Metric_prefix) "mega-" (for 106) is 兆, while a trillion (1012) should always be 万亿, never 兆.

e.g. 一兆字节 (or 一兆 for short) means one megabyte (1 MB), and 一兆赫 means one megahertz (1 MHz).

<http://zjj.beijing.gov.cn/wsbs/infoview.asp?ViewID=50494>

> 10的6次方 兆 M
>
> 10的4次方称为万，10的8次方称为亿，10的12次方称为万亿

---

In Taiwan, most people use 兆 for 1012.


---

### Answer by username_7 on 2018-01-25. Score: 0

In fact, 兆 could be million, trillion, or 10 quadrillions. In China mainland, the word is usually used to indicate million. Like the sentence "The file is 1MB" could translate to "这个文件（的大小是）一兆"（although, we usually just write "1M" or "1MB" instead of "一兆" since it's simpler）. The "兆" in "兆瓦", "兆赫", "兆帕" also means million.
But I heard in Taiwan, it usually means trillion.


---

### Answer by username_8 on 2018-01-24. Score: 0

Edit:

> I might had misunderstood the question. I think the OP is askeing '兆' as '**part of**' a number(unit), for example **兆**瓦 (MW) . Not '兆' as a number itself, for example "一**兆**日圆" is "one **trillion** yen"

~

The text below therefore did not answer the original question, but adding additional information on the character 兆 instead

> <http://www.cantonese.sheik.co.uk/dictionary/characters/1420/>
>
> 兆
>
> million million (China)
>
> trillion (Taiwan)

~

> <https://en.wikipedia.org/wiki/Trillion>
>
> Trillion (short scale) = 1,000,000,000,000; one million million; SI prefix: **tera**-
>
> **the current meaning** in both American and British English

~

> Trillion (long scale) (1,000,000,000,000,000,000); one million million million; SI prefix: **exa**-), the **former meaning** in British English and current usage in many non-English-speaking countries

Since the current meaning of 兆 (trillion) is 'one million million'(China's standard) It should be our standard.

> **Comments:**
> **username_0**: Are you saying that CEDICT needs to be changed to also add "(old)" for million and mega?  And when you say "our," are you referring to this site, or to some Chinese-speaking country?  I have nothing against Cantonese, but I'm currently trying to acquire 普通话.  fefe and user3306356 seem to be saying it is more commonly used for "mega"  
> **username_8**: 兆 in 兆瓦 (MW) is 'one million' ( 瓦) . But '兆 ' itself as a number means 'trillion'  
> **username_9**: @tang ho: the controversial started in ancient time: how to interpret "兆", as 百萬, 萬億 or 億億. this wiki has info: https://zh.wikipedia.org/zh-hk/兆  

---

