万 and 亿 (The 万-Based System)

This is the page that rewires how you think about big numbers. English chunks large numbers into groups of three digits — that is what every comma in 1,000,000 marks, and it gives us the words thousand, million, billion. Chinese chunks by groups of four digits, and its two big place words, 万 (wàn) "ten-thousand" and 亿 (yì) "hundred-million," sit at those four-digit boundaries. Nothing about Chinese numbers is hard once you regroup by four instead of three — but until you do, every number above ten thousand feels like a puzzle. Let's fix that permanently.

The one rule: group by four, not three

Write out where the "commas" fall in each language and the whole difference becomes visible:

Look at the Chinese grouping column: the comma lands after every four zeros. The first four-digit block is counted in plain digits (个十百千); the second block is counted in 万; the third block is counted in 亿. So a Chinese speaker reads a huge number by mentally slicing it into four-digit chunks from the right and naming each chunk's header. This is why there is no single Chinese word for "million" — a million is simply "one hundred 万."

万 = 10,000

万 is the workhorse of everyday large numbers — salaries, house prices, city populations, view counts. Anything from 10,000 up to just under 100 million is expressed as "how many 万." Remember the 两 vs 二 rule bites again here: before 万 a leading "two" is 两, so 20,000 is 两万, not 二万.

Notice 五百万 in the second example: "five million" = 500 万 = 五百万 (wǔbǎi wàn), literally "five-hundred ten-thousands." An English speaker's instinct is to reach for a "million" word that does not exist; instead you count the millions in units of 万. The most common beginner slip is here — see the mistakes below.

For the awkward hundred-thousand, there is no word 百千 ("hundred-thousand"); Chinese climbs 千 → 万 and then keeps stacking. So 100,000 is 十万 (ten 万), and 300,000 is 三十万 (sānshí wàn).

亿 = 100,000,000

The next four-digit boundary up is 亿 = one hundred million (10^8). It shows up whenever you talk about national populations, big companies, or the internet. Above 亿 you do not invent a new word — you count 亿 the same way: 十亿 (a billion), 百亿 (ten billion), 千亿 (hundred billion).

Watch the English "billion" carefully, because it is a false friend: an English billion (10^9) is 十亿 in Chinese (ten 亿), and 8 billion is 八十亿. There is no dedicated Chinese word for "billion" — it is just "ten hundred-millions." Once you internalize the 万/亿 skeleton, even astronomical figures are mechanical: 1,234,567 slices as 123|4567 and reads 一百二十三万四千五百六十七 (yìbǎi èrshísān wàn sìqiān wǔbǎi liùshíqī).

Common Mistakes

1. Inventing 百千 for "hundred thousand." Chinese has no such word — after 千 it jumps to 万.

2. The off-by-100 million error. "Five million" is 500 万, not 5 万 (which is only 50,000).

3. Calquing English 'billion' directly. An English billion is 十亿, not 一亿.

4. Using 二 instead of 两 before 万 or 亿. A leading "two" before these place words is 两.

Key Takeaways

• Chinese groups large numbers by four digits (万, 亿), where English groups by three (thousand, million, billion).
• 万 = 10,000; 亿 = 100,000,000. There is no word for "million" or "billion."
• "A million" = 一百万 (100 × 万); "a billion" = 十亿 (10 × 亿).
• 100,000 = 十万 (there is no 百千); count in 万 all the way to just under 100 million.
• Convert by re-commaing every four digits from the right, then read each chunk with its header — and use 两, not 二, before 万 and 亿.