How to Say “Less Than” with 不到 (bùdào)
不到 (bùdào) means “less than / under / not yet,” literally “doesn't reach (the amount).” Subject + 不到 + Number + (Measure Word) + Noun: 我女儿不到三岁 (“my daughter isn't yet three”), 不到一百块 (“less than 100 kuai”). When 不到 sits before a duration and something happened sooner than expected, add 就…了: 他们认识不到两个月就结婚了 (“they married after knowing each other less than two months”).
Why this trips learners up
The verb 到 (dào) means “arrive / reach,” so 不到 (bùdào) literally means “doesn't reach” a certain amount, which is to say “less than / under / not yet.” The basic frame is Subject + 不到 + Number + (Measure Word) + Noun, placed before whatever quantity falls short: 我女儿不到三岁 (“my daughter isn't yet three”), 这件衣服花了不到一百块 (“this shirt cost less than 100 kuai”), 这个班不到二十个学生 (“this class has fewer than twenty students”).
不到 covers a span of English: “less than” for amounts and money (不到一百块), “under” for ages and limits (在美国不到21岁不能喝酒, “in the US you can't drink under 21”), and “not yet” when something hasn't reached a mark (不到三岁, “not yet three”). What comes after 不到 is always a number with its unit.
There's a second, slightly different pattern. When 不到 sits before a length of time and you're reporting that something happened sooner than expected, you add 就 … 了: Subject + 不到 + Time + 就 + Predicate + 了. 他们认识不到两个月就结婚了 (“they got married after knowing each other less than two months”), 这本书我不到一个星期就看完了 (“I finished this book in under a week”). The 就 is what carries the “so quickly, earlier than you'd think” feeling, so don't leave it out.
不到 is the natural opposite of 多: 多 goes after a number for “more than” (五十多岁, “fifty-something”), while 不到 goes before a number for “less than” (不到五十岁, “under fifty”). One overshoots the mark, the other falls short of it. And note that 不到 needs an actual number; to say one thing is less than another, you use 没有…多 or 比…少, not 不到.
The structure
Colour key
Each colour marks one grammatical role — and the same colour means the same role on every page in the Lab.
Examples in context
Real-world sentences, easiest first. Toggle pinyin or the translation, tap any word to see its role, or play the audio.
Tap a word to see its grammatical role.
wǒ dìdi 我弟弟 Subject hái 还 Adverb bùdào 不到 Pattern shí 十 Number suì 岁 Measure word
My little brother isn't even ten yet (不到 before the number).
zhè dùn fàn 这顿饭 Subject yígòng 一共 Adverb huā 花 Verb le 了 Function word bùdào 不到 Pattern wǔshí 五十 Number kuài 块 Measure word
This meal cost less than fifty kuai in total (不到 + money).
zhège bān 这个班 Subject bùdào 不到 Pattern èrshí 二十 Number gè 个 Measure word xuéshēng 学生 Object
This class has fewer than twenty students (不到 + number + measure word + noun).
cóng wǒ jiā dào dìtiězhàn 从我家到地铁站 Other bùdào 不到 Pattern sānbǎi 三百 Number mǐ 米 Measure word
It's less than 300 metres from my home to the subway station (不到 + distance).
zhè běn shū 这本书 Object wǒ 我 Subject bùdào 不到 Pattern yí gè xīngqī 一个星期 Time jiù 就 Adverb kàn wán 看完 Verb le 了 Function word
I finished this book in less than a week (不到 + time + 就…了).
tāmen 他们 Subject bùdào 不到 Pattern yì nián 一年 Time jiù 就 Adverb fēnshǒu 分手 Verb le 了 Function word
They broke up in less than a year (不到一年就…了, sooner than expected).
xīn chǎnpǐn 新产品 Subject shàngshì 上市 Verb bùdào 不到 Pattern yí gè yuè 一个月 Time jiù 就 Adverb mài guāng 卖光 Verb le 了 Function word
The new product sold out within a month of launching (不到一个月就…了).
tā 她 Subject dàxué bìyè 大学毕业 Other bùdào 不到 Pattern sān nián 三年 Time jiù 就 Adverb dāng shàng le jīnglǐ 当上了经理 Verb
Less than three years after graduating, she became a manager (不到三年就…了).
Common mistakes
Why it happens: When 不到 is before a duration and you're reporting something that happened sooner than expected, you need 就 (and 了): 他们认识不到两个月就结婚了, not …不到两个月结婚了. The 就 carries the “so quickly” meaning; without it the sentence feels unfinished.
Why it happens: For “less than [a quantity]” in everyday speech, use 不到, not 少. “Less than 100 kuai” is 不到一百块, not 少一百块, because 少 means “few / lacking,” not “less than a number.” 不到 is the one that means “under” an amount.
Why it happens: 不到 needs an actual number or amount (不到一百块, 不到三岁). To say one thing is less than another, use 没有…多 or 比…少: “I have less money than you” is 我的钱没有你多 / 我的钱比你少, not 我的钱不到你.
Compare & contrast
| 不到 + number = less than / under | number + 多 = more than / over | The difference |
|---|---|---|
| 不到五十岁bùdào wǔshí suì | 五十多岁wǔshí duō suì | 不到五十岁 means under fifty, not yet reaching it; 五十多岁 means fifty-something, just past it. 不到 goes before the number, 多 goes after it. Below versus above the mark. |
| 不到一百块bùdào yìbǎi kuài | 一百多块yìbǎi duō kuài | 不到一百块 is less than 100 kuai; 一百多块 is a hundred-and-something. 不到 falls short of the number; 多 overshoots it. |
Try it yourself
Say “My little brother isn't even ten yet.” Put 不到 before the number.
Related patterns
Quick reference card
How to Say “Less Than” with 不到 (bùdào) grammar.merrymandarin.com A pocket summary — print it and keep it by your desk.