# Lakh, crore, million and billion converter (number to words)

> Convert lakh and crore to million and billion, and write any number in words in the Indian and international systems, or turn words back into digits.

交互版本：https://www.calcopenly.com/zh/conversion/lakh-crore-million-billion-converter
主题：单位换算器

The Indian and international systems name the same digits in different groups. The Indian system counts thousand (10³), lakh (10⁵) and crore (10⁷), with a comma after the hundreds and then after every two digits: 1,23,45,678. The international system counts thousand, million (10⁶) and billion (10⁹) in steps of three digits: 12,345,678. The converter reads digits, short forms such as 2.5 crore, or English words, and writes the number both ways.

People use it to turn figures quoted in lakh and crore into millions and billions, and to write an amount in words on a cheque or contract. The default, 1,23,45,678, reads as one crore twenty-three lakh forty-five thousand six hundred seventy-eight, which is about 12.35 million.

Beyond a crore, the number of crores is read with the same names, so 10¹² is one lakh crore. Words follow US style without “and”, and the international names use the short scale up to decillion (10³³).

## 输入

- **Number or words**: Digits in any grouping (1,23,45,678 or 12,345,678), short forms (2.5 crore, 3.2 million) or words (one lakh twenty thousand)

## 结果

- In words, Indian system — 主要结果
- In words, international system
- Indian grouping
- International grouping
- In lakh or crore
- In thousand, million, billion…

## 公式

$$
\begin{aligned} 1\ \text{lakh} &= 10^{5} = 0.1\ \text{million} \\ 1\ \text{crore} &= 10^{7} = 10\ \text{million} \\ 100\ \text{crore} &= 10^{9} = 1\ \text{billion} \\ 1\ \text{lakh crore} &= 10^{12} = 1\ \text{trillion} \end{aligned}
$$

## 计算示例

### 1,23,45,678 in words

- Number or words: 12345678
- **In words, Indian system: one crore twenty-three lakh forty-five thousand six hundred seventy-eight**
- **In words, international system: twelve million three hundred forty-five thousand six hundred seventy-eight**
- **Indian grouping: 1,23,45,678**
- **International grouping: 12,345,678**
- **In lakh or crore: 1.2345678 crore**
- **In thousand, million, billion…: 12.345678 million**
- 核验来源：Independent Python implementation of both scales (lakh = 10⁵, crore = 10⁷, million = 10⁶); hand check 1×10⁷ + 23×10⁵ + 45×10³ + 678

### 2.5 crore in millions

- Number or words: 2.5 crore
- **In words, international system: twenty-five million**
- **Indian grouping: 2,50,00,000**
- **In thousand, million, billion…: 25 million**
- 核验来源：2.5 × 10⁷ = 25 × 10⁶

### Words to digits: one lakh twenty thousand

- Number or words: one lakh twenty thousand
- **International grouping: 120,000**
- **In lakh or crore: 1.2 lakh**
- **In words, international system: one hundred twenty thousand**
- 核验来源：10⁵ + 20 × 10³ = 120,000

### Large: one lakh crore is one trillion

- Number or words: 1000000000000
- **In words, Indian system: one lakh crore**
- **In words, international system: one trillion**
- **Indian grouping: 10,00,00,00,00,000**
- 核验来源：10⁵ × 10⁷ = 10¹² = one trillion (short scale); Indian grouping puts commas every two digits above the thousands

### 30-digit integer (BigInt)

- Number or words: 123456789012345678901234567890
- **In words, international system: one hundred twenty-three octillion four hundred fifty-six septillion seven hundred eighty-nine sextillion twelve quintillion three hundred forty-five quadrillion six hundred seventy-eight trillion nine hundred one billion two hundred thirty-four million five hundred sixty-seven thousand eight hundred ninety**
- **In words, Indian system: twelve crore thirty-four lakh fifty-six thousand seven hundred eighty-nine crore one lakh twenty-three thousand four hundred fifty-six crore seventy-eight lakh ninety thousand one hundred twenty-three crore forty-five lakh sixty-seven thousand eight hundred ninety**
- **Indian grouping: 1,23,45,67,89,01,23,45,67,89,01,23,45,67,890**
- 核验来源：Independent Python implementation using integer arithmetic (short scale to decillion; Indian crore read recursively)

### Zero

- Number or words: 0
- **In words, Indian system: zero**
- **In words, international system: zero**
- 核验来源：Definition

## 常见问题

### How many lakhs make a million?

Ten. A lakh is 100,000 (10⁵) and a million is 1,000,000 (10⁶), so 10 lakh = 1 million and 1 lakh = 0.1 million. Going the other way, 2.5 million is 25 lakh. In Indian grouping 10 lakh is written 10,00,000: the first comma comes three digits from the right, then one after every two digits.

### How many crores are in a billion?

One hundred. A crore is 10,000,000 (10⁷) and a billion in the short scale used in English is 1,000,000,000 (10⁹), so 1 billion = 100 crore and 1 crore = 10 million. The old Indian name for 100 crore is arab, and 100 arab (10¹¹) is kharab. A trillion (10¹²) is 1 lakh crore.

### How do you write 1 crore in numbers?

1,00,00,000 in Indian grouping, or 10,000,000 in international grouping: a 1 followed by seven zeros. Indian grouping puts a comma after the hundreds and then after every two digits, so the commas mark thousand, lakh and crore. 50 crore is written 50,00,00,000, which is 500 million.

### Which amount counts on a cheque if the words and figures differ?

The words. Section 18 of India's Negotiable Instruments Act, 1881 says that when an amount is stated differently in figures and in words, the amount stated in words is the amount to be paid; the US Uniform Commercial Code §3-114 has the same rule. Adding “and” or “only” to the words does not change the value.

### Is a billion a thousand million or a million million?

A thousand million (10⁹) in current English, the short scale. The UK government adopted it in 1974, when Prime Minister Harold Wilson told Parliament that billion was used internationally to mean 1,000 million. French, German, Italian and Spanish still use the long scale, in which their word for billion means 10¹² and 10⁹ is called a milliard in French or Milliarde in German.

### “Lakh, crore, million and billion converter (number to words)”有多准确？

准确性取决于输入值和方法的假设。十进制运算使用50位有效数字，但估算、数值方法和源数据的精度可能较低；显示时的舍入并不能消除这些限制。 已按独立来源核验的计算示例：7。 例如，“1,23,45,678 in words”根据Independent Python implementation of both scales (lakh = 10⁵, crore = 10⁷, million = 10⁶); hand check 1×10⁷ + 23×10⁵ + 45×10³ + 678进行核验。

### 这种方法出自哪里？

Wikipedia — Indian numbering system (lakh, crore, lakh crore); Wikipedia — Names of large numbers (short scale: million … decillion).

## 来源

- [Wikipedia — Indian numbering system (lakh, crore, lakh crore)](https://en.wikipedia.org/wiki/Indian_numbering_system)
- [Wikipedia — Names of large numbers (short scale: million … decillion)](https://en.wikipedia.org/wiki/Names_of_large_numbers)