Indian numbering system

There are words for numbers larger than 1 crore as well, but these are not commonly used and are unfamiliar to most. These include 1 arab (equal to 100 crore or 1 billion), 1 kharab (equal to 100 arab or 100 billion), 1 nil (sometimes incorrectly transliterated as neel; equal to 100 kharab or 10 trillion), 1 padma (equal to 100 nil or 1 quadrillion), 1 shankh (equal to 100 padma or 100 quadrillion), and 1 mahashankh (equal to 100 shankh or 10 quintillion). In common parlance, the thousand, lakh, and crore terminology (though inconsistent) repeats for larger numbers: thus 1,000,000,000,000 (one trillion) becomes 1 lakh crore, written as 10,00,00,00,00,000.

The Indian numbering system corresponds to the Western system for the zeroth through fourth powers of ten: one (10⁰), ten (10¹), one hundred (10²), one thousand (10³), ten thousand (10⁴). For higher powers of ten, the names no longer correspond. In the Indian system, the next powers of ten are called one lakh, ten lakh, one crore, ten crore, one arab (or one hundred crore), and so on; there are new words for every second power of ten (10^{5 + 2n}): lakh (10⁵), crore (10⁷), arab (10⁹), etc. In the Western system, the next powers of ten are called one hundred thousand, one million, ten million, one hundred million, one billion, and so on; there are new words for every third power of ten (10³ⁿ): million (10⁶), billion (10⁹), trillion (10¹²), etc.

The written numbers differ only in the placement of commas, which group the digits into powers of one hundred in the Indian system (except for the first thousand), and into powers of one thousand in the Western system. The Indian and most English systems both use the decimal point and the comma digit-separator, while some other languages and countries using the Western numbering system use the decimal comma and the thin space or point to group digits.

The Indian numbering system uses separators differently from the international norm. Instead of grouping digits by threes as in the international system, the Indian numbering system groups the rightmost three digits together (until the hundreds place), and thereafter groups by sets of two digits.[2] One trillion would thus be written as 10,00,00,00,00,000 or 10 kharab (or one lakh crore). This makes the number convenient to read using the system's terminology. Thus:

This accords with the Indian numbering system, which has units for thousands, hundreds of thousands, tens of millions, etc.

The table below follows the short scale usage of one billion being one thousand million. In India, Bangladesh and Pakistan, following former British usage, the long scale was used, with one billion equivalent to one million million.

There are various systems of numeration found in various ancient Vedic literary works of India. The following table gives one such system used in the Valmiki Ramayana.[4]

• In Assamese, a lakh is also called লক্ষ lokhyo, or লাখ lakh and a crore is called কৌটি বা কোটি kouti
• In Bengali, a lakh is natively (tadbhava) known as লাখ lākh, though some use the ardha-tatsama লক্ষ lokkho. A crore is called কোটি kōṭi
• In Burmese, crore is called ကုဋေ [ɡədè]. Lakh is used in Burmese English.
• In Gujarati, a lakh is called લાખ lākh and a crore is called કરોડ karoḍ. A hundred crore is called અબજ abaj
• In Kannada, a lakh is called ಲಕ್ಷ lakṣha and a crore is called ಕೋಟಿ kōṭi
• In Khasi, a lakh is called lak and a crore is called klur or krur. A billion is called arab and hundred billion is called kharab.
• In Malayalam, a lakh is called ലക്ഷം laksham and a crore is called കോടി kodi.
• In Marathi, a lakh is called लाख/लक्ष lākh and a crore is called कोटी koṭi or करोड karoḍ, and an arab (10⁹) is called अब्ज abja.
• In Nepali, a lakh is called लाख lākh and a crore is called करोड karoḍ.
• In Odia, a lakh is called ଲକ୍ଷ lakhya and a crore is called କୋଟି koti.
• In Punjabi, a lakh is called lakkh (Shahmukhi: لکھ, Gurmukhi: ਲੱਖ) and a crore is called karoṛ (Shahmukhi: کروڑ, Gurmukhi: ਕਰੋੜ).
• In Rohingya, a lakh is called lák and a crore is called kurul. A thousand crore is called kuthí.
• In Sinhala, a lakh is called ලක්ෂ lakṣa and a crore is called කෝටි kōṭi.
• In Tamil, a lakh is called இலட்சம் ilatcham and a crore is called கோடி kodi.
• In Telugu, a lakh is called లక్ష lakṣha and a crore is called కోటి kōṭi.
• In Urdu, a lakh is called لاکھ lākh and a crore is called کروڑ karoṛ. A billion is called arab (ارب), and one hundred billion/arab is called a kharab (کھرب).
• Lakh has entered the Swahili language as "laki" and is in common use.

Formal written publications in English in India tend to use lakh/crore for Indian currency and International numbering for foreign currencies.[5]

The usage of this system is limited to the nations of India, Pakistan, Bangladesh, Myanmar and Sri Lanka.[6]

Most institutions and citizens in India use Indian number system, though the Reserve Bank of India has been noted as an exception.[7]