<p>Technically, when you say "增加了n倍", "n倍" is describing the <em>difference</em> the two number. So the original <code>x</code> becomes <code>x*(n+1)</code>, while the difference is <code>n*x</code>.</p>

<p>If you want to say that the latter number is just <code>n</code> times the former, then it is "增加<strong>到</strong>了(原来的)n倍"</p>

<p>However, in casual speech, people may not always respect this rule, which makes it confusing. Sometimes we have to make a confirmation to make sure we get the real number.</p>

CC BY-SA 4.0
2018-05-26T12:02:45.530Z
2018-05-26T12:02:45.530Z
fefe
<p>They both express doubled.</p>

<p>It’s a bit like how:</p>

<ul>
<li>a 100% increase (一倍)</li>
</ul>

<p>is the same as </p>

<ul>
<li>a two-fold increase (两倍)</li>
</ul>

<p>A phenomenon that is equally confusing in English.</p>

<hr>

<p>Compare: <strong>一倍</strong> example sentences from <em>ABC</em></p>

<blockquote>
  <p>这座城市将要扩展一倍。 
  Zhè ⁴zuò chéngshì jiāngyào kuòzhǎn yị̄ ²bèi.
  This city will double its size. </p>
  
  <p>学生人数增加了一倍。 
  Xuésheng rénshù zēngjiāle yị̄ ²bèi.
  The number of students has doubled. </p>
</blockquote>

<p>and <strong>两倍</strong> example sentences from <em>Tuttle</em></p>

<blockquote>
  <p>他的收人是三年前的两倍。 
  Tā de shōurén shì sān nián qián de liǎng bèi.
  His income is double what it was three years ago. </p>
  
  <p>他现在挣的钱是先前工作的两倍。 
  Tā xiànzài zhèng de qián shì xiānqián gōngzuò de liǎng bèi.
  He's earning twice as much as in his previous job. </p>
</blockquote>

CC BY-SA 4.0
2018-05-26T23:40:56.863Z
Are you aware of the difference between  扩展/增加n倍 and X是Y的n倍？
dan
CC BY-SA 4.0
2018-05-28T07:32:42.260Z
@dan Of course. Unless I misunderstood the question I believe that OP's issue is how 一倍 and 两倍 can mean the same thing. So I decided to use this angle to show how they both mean double.
Mou某
CC BY-SA 4.0
2018-05-26T11:43:09.060Z
2018-05-26T15:11:26.770Z
2018-05-26T15:11:26.770Z
Mou某
<p>Math:</p>

<p>倍 means multiple X * 1,</p>

<p>增加了一倍 means x + x * 1, </p>

<p>增加了2 倍 means x + x * 2</p>

<p>某某是它的2倍  means 某某 =  x * 2 </p>

<p>某某是它的1倍 means 某某 = x * 1, = x.</p>

<p>So, 我的分数是你的一倍 imply scores are equal technically.</p>

<p>The right one should be 我的分数比你多一倍.</p>

CC BY-SA 4.0
2018-05-26T12:04:17.567Z
2018-05-26T12:04:17.567Z
sfy
<p>倍 is <em>time</em> in English. However, there are few expressions/phrases that can make difference when they are used in a sentence. I try to summarize a bit: </p>

<ol>
<li><p>X 比 Y 增加n倍: X = Y*(n+1);</p></li>
<li><p>X 是 Y 的n倍: X = Y*n;</p></li>
<li><p>X 比 Y 多n倍: X = Y*(n+1);</p></li>
</ol>

<p>Those phrases are clear and will not cause any confusion.</p>

<p>In fact, the most confusing phrase is X 比 Y翻n倍. Some take it as X = Y<em>n, some think X = Y</em>(n+1), and some even think X = Y* 2^n. I indeed don't have any official answer for this so far.</p>

CC BY-SA 4.0
2018-05-26T13:10:35.147Z
2018-05-26T13:10:35.147Z
dan
<p>I stumbled upon these 2 sentences:</p>

<p><code>这个城市人口比十年前增加了一倍</code></p>

<p><code>这个城市人口比十年前增加了两倍</code></p>

<p><code>The city’s population has doubled from a decade ago</code></p>

<p>I though <code>倍</code> always multiplies the number standing in front of it, it seems like in case of <code>一</code></p>

<p>How come? Is there any logical explanation? </p>

CC BY-SA 4.0
2018-05-26T18:15:18.623Z
这个城市人口比十年前增加了一倍 = 这个城市人口是十年前的两倍, 这个城市人口比十年前增加了两倍 = 这个城市人口是十年前的三倍.
xenophōn
CC BY-SA 4.0
2018-05-26T19:27:04.373Z
users suggest suspecting existence at this site of previous discussions of this matter, searching site seems to confirm such suspicion, see esp. https://chinese.stackexchange.com/questions/9295/when-to-use-%e4%b8%80%e5%80%8d-vs-%e4%b8%a4%e5%80%8d
user6065
<characters><simplified-characters><comparison>
Saying 'doubled' in Chinese 一倍 vs 两倍
# Saying 'doubled' in Chinese 一倍 vs 两倍

(Asked by: username_0 on 2018-05-26)

I stumbled upon these 2 sentences:

`这个城市人口比十年前增加了一倍`

`这个城市人口比十年前增加了两倍`

`The city’s population has doubled from a decade ago`

I though `倍` always multiplies the number standing in front of it, it seems like in case of `一`

How come? Is there any logical explanation?

**Tags:** characters, simplified-characters, comparison

> **Comments:**
> **username_1**: 这个城市人口比十年前增加了一倍 = 这个城市人口是十年前的两倍, 这个城市人口比十年前增加了两倍 = 这个城市人口是十年前的三倍.  
> **username_2**: users suggest suspecting existence at this site of previous discussions of this matter, searching site seems to confirm such suspicion, see esp. https://chinese.stackexchange.com/questions/9295/when-to-use-%e4%b8%80%e5%80%8d-vs-%e4%b8%a4%e5%80%8d  

---

## 4 answers

### Answer by username_3 on 2018-05-26. Score: 4

Technically, when you say "增加了n倍", "n倍" is describing the *difference* the two number. So the original `x` becomes `x*(n+1)`, while the difference is `n*x`.

If you want to say that the latter number is just `n` times the former, then it is "增加**到**了(原来的)n倍"

However, in casual speech, people may not always respect this rule, which makes it confusing. Sometimes we have to make a confirmation to make sure we get the real number.


---

### Answer by username_4 on 2018-05-26. Score: 2

They both express doubled.

It’s a bit like how:

* a 100% increase (一倍)

is the same as

* a two-fold increase (两倍)

A phenomenon that is equally confusing in English.

---

Compare: **一倍** example sentences from *ABC*

> 这座城市将要扩展一倍。
> Zhè ⁴zuò chéngshì jiāngyào kuòzhǎn yị̄ ²bèi.
> This city will double its size.
>
> 学生人数增加了一倍。
> Xuésheng rénshù zēngjiāle yị̄ ²bèi.
> The number of students has doubled.

and **两倍** example sentences from *Tuttle*

> 他的收人是三年前的两倍。
> Tā de shōurén shì sān nián qián de liǎng bèi.
> His income is double what it was three years ago.
>
> 他现在挣的钱是先前工作的两倍。
> Tā xiànzài zhèng de qián shì xiānqián gōngzuò de liǎng bèi.
> He's earning twice as much as in his previous job.

> **Comments:**
> **username_5**: Are you aware of the difference between  扩展/增加n倍 and X是Y的n倍？  
> **username_4**: @username_5 Of course. Unless I misunderstood the question I believe that OP's issue is how 一倍 and 两倍 can mean the same thing. So I decided to use this angle to show how they both mean double.  

---

### Answer by username_6 on 2018-05-26. Score: 1

Math:

倍 means multiple X \* 1,

增加了一倍 means x + x \* 1,

增加了2 倍 means x + x \* 2

某某是它的2倍 means 某某 = x \* 2

某某是它的1倍 means 某某 = x \* 1, = x.

So, 我的分数是你的一倍 imply scores are equal technically.

The right one should be 我的分数比你多一倍.


---

### Answer by username_5 on 2018-05-26. Score: 1

倍 is *time* in English. However, there are few expressions/phrases that can make difference when they are used in a sentence. I try to summarize a bit:

1. X 比 Y 增加n倍: X = Y\*(n+1);
2. X 是 Y 的n倍: X = Y\*n;
3. X 比 Y 多n倍: X = Y\*(n+1);

Those phrases are clear and will not cause any confusion.

In fact, the most confusing phrase is X 比 Y翻n倍. Some take it as X = Y*n, some think X = Y*(n+1), and some even think X = Y\* 2^n. I indeed don't have any official answer for this so far.


---

