倍 (bèi) is the word for a multiple — "times, -fold." In its clean, static use it behaves exactly like English "times": 三倍 (sān bèi) is "three times / triple," 十倍 (shí bèi) is "tenfold." The trouble — and it is real trouble that trips native English speakers, translators, and even careless native writers — starts the moment 倍 is attached to a verb of change. 增加了三倍 does not mean "increased to three times"; it means "increased by three-fold," which lands you at four times the original. This page separates the two frames so cleanly that you will never miscount again. Note first that 倍 is a measure-word-like counter, so "two times" is 两倍 (liǎng bèi) with 两, not 二 — the same rule as any measure word.
The clean multiplier: A 是 B 的 X 倍
The safest, most unambiguous frame is A 是 B 的 X 倍 — "A is X times B." Here 倍 works precisely like English "times": the number is the final ratio. A 是 B 的三倍 means A = 3 × B, full stop. No hidden arithmetic.
这个房子是那个的三倍大。
zhège fángzi shì nàge de sān bèi dà
This house is three times as big as that one.
他的工资是我的两倍。
tā de gōngzī shì wǒ de liǎng bèi
His salary is twice mine.
北京的房价是我们这儿的好几倍。
Běijīng de fángjià shì wǒmen zhèr de hǎo jǐ bèi
Housing prices in Beijing are several times what they are here.
Whenever you can phrase the fact as "A is X times B," reach for 是…的 X 倍 and the number stays honest: 两倍 = twice, 三倍 = triple, 十倍 = tenfold. This is also the frame to fall back on whenever the increase-verb frames below start to feel slippery — you can almost always recast a change as a final ratio and sidestep the +1 problem entirely.
The +1 trap: 增加了 X 倍 vs 增加到 X 倍
Now the crux. With a verb of increase — 增加 (increase), 增长 (grow), 提高 (raise) — the little words 了 and 到 point at two different things, and getting them mixed up is off by a whole multiple.
- 增加了 X 倍 — 了 marks the amount added. The growth itself equals X times the original, and that growth sits on top of the original. Final = (X + 1) × original.
- 增加到 X 倍 — 到 marks the endpoint reached. The final value simply is X times the original. Final = X × original.
| Expression | Literally | Final value |
|---|---|---|
| 增加到两倍 | increase TO two-fold | 2× original |
| 增加了一倍 | increase BY one-fold (+100%) | 2× original (doubled) |
| 增加了两倍 | increase BY two-fold (+200%) | 3× original (tripled) |
| 增加到三倍 | increase TO three-fold | 3× original |
Read that table until the pattern clicks: 增加了一倍 = 增加到两倍 (both mean doubled), and 增加了两倍 = 增加到三倍 (both mean tripled). The 了 versions always run one behind the 到 versions, because "increased by one-fold" adds the original back on top of itself.
这几年公司的产量增加了一倍。
zhè jǐ nián gōngsī de chǎnliàng zēngjiā le yí bèi
Over the past few years the company's output has doubled (increased by 100%).
他的收入增加了两倍，现在是原来的三倍。
tā de shōurù zēngjiā le liǎng bèi, xiànzài shì yuánlái de sān bèi
His income has tripled — it increased by two-fold, so it's now three times the original.
订单量增长到两倍，我们得多招几个人。
dìngdānliàng zēngzhǎng dào liǎng bèi, wǒmen děi duō zhāo jǐ ge rén
Order volume has doubled (grown to twice) — we need to hire a few more people.
The second example is the cleanest cure: 增加了两倍 and 是原来的三倍 describe the same fact, and native writers routinely pair them so the reader can't miscount. When in doubt, say the final ratio out loud with 是…的 X 倍 and check it against your 了/到 phrasing.
比 comparisons, why 减少 rejects 倍, and 翻番
The 比 comparison frame — A 比 B 多/大 X 倍 — behaves like the 了 frame: the multiple is the excess over B, so it too carries the +1. A 比 B 多一倍 means A exceeds B by one B, i.e. A = 2B; A 比 B 多两倍 means A = 3B. This is the degree of difference in a 比 sentence, and it produces the notorious clash you must hold in your head:
| Sentence | Real relationship |
|---|---|
| A 是 B 的两倍 | A = 2B (twice) |
| A 比 B 多一倍 | A = 2B (twice) — same fact, different number! |
| A 比 B 多两倍 | A = 3B (triple) |
今年的游客比去年多了一倍。
jīnnián de yóukè bǐ qùnián duō le yí bèi
There were twice as many tourists this year as last (one-fold more).
Two honest, hard points. First, 减少 (decrease) does not take 倍. You cannot "decrease by a multiple" — a full one-fold decrease would already be 100%, and more is impossible. So a drop is expressed with a fraction or percentage: 减少了一半 (halved), 减少了百分之三十 (down 30%). You'll occasionally hear a sloppy 减少了一倍 meaning "halved," but grammarians condemn it — don't imitate it.
今年的成本减少了一半。
jīnnián de chéngběn jiǎnshǎo le yíbàn
Costs were cut in half this year.
Second, 翻番 is not the same as 倍. 翻一番 (fān yì fān) means to double (×2), but the multiplication stacks: 翻两番 (fān liǎng fān) is ×4, 翻三番 is ×8 — 翻 N 番 = ×2ᴺ. This is a favourite exam and news trap: 翻两番 is quadruple, not double.
公司计划五年内产值翻两番。
gōngsī jìhuà wǔ nián nèi chǎnzhí fān liǎng fān
The company plans to quadruple its output value within five years (翻两番 = ×4).
Common Mistakes
1. Reading 增加了三倍 as 'increased to three times.' With 了 the multiple is the added amount, so the final value is four times the original.
❌ 增加了三倍 = 现在是三倍
Incorrect — 增加了三倍 is +300%, so the final value is FOUR times the original.
✅ 增加了三倍，是原来的四倍。
zēngjiā le sān bèi, shì yuánlái de sì bèi
Increased by three-fold — now four times the original.
2. Using 二倍 instead of 两倍. 倍 is a measure-word-like counter, so "two" before it is 两.
❌ 他的工资是我的二倍。
Unnatural — before 倍 use 两, not 二: 两倍.
✅ 他的工资是我的两倍。
tā de gōngzī shì wǒ de liǎng bèi
His salary is twice mine.
3. Using 倍 with 减少. Decreases can't be expressed as a multiple; use a fraction or percentage.
❌ 产量减少了一倍。
Illogical — you can't decrease by a whole multiple; say 减少了一半 (halved).
✅ 产量减少了一半。
chǎnliàng jiǎnshǎo le yíbàn
Output was cut in half.
4. Treating 翻两番 as 'doubled.' 翻番 stacks powers of two: 翻两番 is ×4.
❌ 翻两番就是变成两倍。
Incorrect — 翻两番 is ×4 (quadruple); 翻一番 is the one that means double.
✅ 翻两番就是变成四倍。
fān liǎng fān jiùshì biànchéng sì bèi
翻两番 means becoming four times as much.
Key Takeaways
- A 是 B 的 X 倍 is the clean multiplier: the number equals the final ratio (三倍 = three times). Default to this frame.
- 增加了 X 倍 = increased by X-fold = (X+1)× original; 增加到 X 倍 = increased to X-fold = X× original. So 增加了一倍 = 增加到两倍 = doubled.
- 比…多/大 X 倍 carries the same +1: A 比 B 多一倍 means A = 2B (same fact as A 是 B 的两倍, one number lower).
- Use 两倍, not 二倍 — 倍 is measure-word-like.
- 减少 rejects 倍 (use a fraction/percentage: 减少了一半); and 翻 N 番 = ×2ᴺ, so 翻两番 is quadruple, not double.
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Start learning Chinese→Related Topics
- Fractions (三分之一)HSK 3 — Chinese states fractions denominator-first with the frame X 分之 Y ('of X parts, Y'): 三分之一 = 1/3, 四分之三 = 3/4. The order is the exact reverse of English, and 之 is the classical 'of'.
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- Basic Arithmetic (加减乘除)HSK 3 — Spoken math in Chinese: 加 (+), 减 (−), 乘 (×), 除以 (÷), joined by 等于 (=). 二加三等于五 = '2 + 3 = 5'. Reads left-to-right like English — but 除 and 除以 flip the order.
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