5 converters — Convert between number bases, Indian notation, and Roman numerals
Convert numbers between binary, octal, decimal, and hexadecimal bases. Reformat numbers between Indian notation (lakhs, crores) and international notation (millions, billions).
The Numbers category contains converters for number representation — how the same value is expressed in different bases, different scale systems, or in written words. These are essential tools for programmers, finance professionals, students, and anyone working across Indian and international number conventions.
Number bases: the programmer's toolkit
The Number Base Converter converts between the four number bases encountered in computing: decimal (base 10, everyday use), binary (base 2, machine representation), octal (base 8, Unix permissions), and hexadecimal (base 16, memory addresses, colour codes).
Understanding base conversions is fundamental for anyone studying computer science, working in embedded systems, or reading technical documentation. The relationship between binary and hexadecimal is particularly elegant: every 4 binary bits map to exactly one hex digit, making hex a compact shorthand for binary data. The Number Base Converter is useful both for manual verification and for quickly translating hex colour codes, chmod values, and memory addresses.
Indian vs international number scales
The Indian Number Converter addresses one of the most persistent sources of confusion for Indian users consuming international financial media, and vice versa. When Bloomberg reports a company's revenue in "billions," an Indian reader must mentally convert to crore. When an Indian CFO reports ₹50,000 crore revenue, an international investor must convert to USD billions.
1 crore = 10 million. 100 crore = 1 billion. 10 lakh crore = 1 trillion. These conversions appear constantly in India's financial press — GDP figures, Union Budget allocations, company valuations, and infrastructure project costs are all quoted in crore or lakh crore.
Numbers in words for documents and cheques
The Number to Word Converter is a practical tool for formal document preparation. Bank cheques, demand drafts, sale deeds, and legal contracts in India require amounts written in full words — "Rupees Fifty-Three Lakh Twenty-Two Thousand Four Hundred and Sixty Only." Errors in word representation can invalidate cheques or create contractual ambiguity. The converter produces the correct Indian English word form for any numeric value.
Frequently Asked Questions
What number system converters are available?
The Numbers category includes three converters: the [Number Base Converter](/number-base-converter/) (binary, octal, decimal, hexadecimal), the [Indian Number Converter](/indian-number-converter/) (crore, lakh, thousand, million, billion), and the [Number to Word Converter](/number-to-word-converter/) (numeral to English words). Together they cover the most common number representation and notation challenges.
How do I convert a decimal number to binary?
To convert decimal to binary, repeatedly divide by 2 and record the remainders from bottom to top. For example, 13 ÷ 2 = 6 remainder 1; 6 ÷ 2 = 3 remainder 0; 3 ÷ 2 = 1 remainder 1; 1 ÷ 2 = 0 remainder 1 — reading remainders bottom to top gives 1101. The [Number Base Converter](/number-base-converter/) handles conversions between decimal (base 10), binary (base 2), octal (base 8), and hexadecimal (base 16) instantly, including for large numbers where manual calculation is error-prone.
What is hexadecimal and where is it used?
Hexadecimal (base 16) uses digits 0–9 and letters A–F to represent values 0–15. It is widely used in computing because one hex digit represents exactly 4 binary bits (a nibble), making it a compact representation of binary data. Common uses include HTML colour codes (#FF5733), MAC addresses (00:1A:2B:3C:4D:5E), memory addresses (0x7FFF1234), and byte-level data representation in debugging. The [Number Base Converter](/number-base-converter/) converts between hex and decimal in both directions.
What is the difference between lakh, crore, and million?
1 lakh = 100,000 (one hundred thousand). 1 crore = 10,000,000 (ten million). 1 million = 1,000,000 (ten lakhs). 1 billion = 1,000,000,000 (100 crores). The Indian numbering system groups digits differently: after the first three digits (hundreds), further digits group in pairs of two — so one crore is written as 1,00,00,000 not 10,000,000. The [Indian Number Converter](/indian-number-converter/) converts between Indian and international scale nomenclature instantly.
How does the Indian numbering system differ from the international system?
The international system groups large numbers in sets of three digits: thousand, million, billion, trillion. The Indian system groups in two after the first thousand: lakh (10⁵), crore (10⁷), arab (10⁹), kharab (10¹¹). This means 10 million is '1 crore' in Indian usage, not a single named unit in the international system. Financial news, government budgets, and stock market reports in India exclusively use crore and lakh — the [Indian Number Converter](/indian-number-converter/) bridges these for anyone reading international financial coverage.
How do I write a number in words in Indian English?
Indian English uses lakh and crore for large numbers, not million and billion. 1,00,000 is 'one lakh'; 10,00,000 is 'ten lakh'; 1,00,00,000 is 'one crore'; 10,00,00,000 is 'ten crore'. For cheques, official documents, and legal contracts, numbers must be written in words. The [Number to Word Converter](/number-to-word-converter/) converts any numeral to its Indian English word form instantly, eliminating errors in large-value documents.
What is octal number system and where is it used?
Octal (base 8) uses digits 0–7. It was historically important in early computing because it compactly represents binary data in 3-bit groups. Today it is most commonly encountered in Unix/Linux file permission notation — chmod 755 means owner=7 (rwx), group=5 (r-x), others=5 (r-x) in octal. It is less common than hexadecimal for modern computing but still appears in embedded systems and assembly programming. The [Number Base Converter](/number-base-converter/) includes octal alongside binary and hexadecimal.
What are the place values in the Indian number system?
Indian place values from right: ones (1), tens (10), hundreds (100), thousands (1,000), ten-thousands (10,000), lakhs (1,00,000), ten-lakhs (10,00,000), crores (1,00,00,000), ten-crores (10,00,00,000), hundreds of crores (1,00,00,00,000). After crore, Indian terms include arab (1,000 crore), kharab, neel, padma, shankh — though these are rarely used in modern financial or commercial contexts. The [Indian Number Converter](/indian-number-converter/) covers units from one through quintillion.
What is the binary representation of common IP address components?
In IPv4, each address consists of four octets (8-bit numbers, values 0–255) separated by dots. The address 192.168.1.1 in binary is 11000000.10101000.00000001.00000001. Subnet masks (e.g. 255.255.255.0) are also written in binary as 11111111.11111111.11111111.00000000. Network engineers frequently convert between decimal and binary for subnetting. The [Number Base Converter](/number-base-converter/) handles 8-bit to 32-bit values efficiently.
How many digits does one crore have?
One crore (1,00,00,000) has 8 digits in the Indian comma notation, written as 1 followed by seven zeros. In international notation, it is written as 10,000,000 — the same 8 digits grouped differently. On a calculator or spreadsheet using international notation, one crore appears as 1E+7 (scientific notation) or 10,000,000. The [Indian Number Converter](/indian-number-converter/) converts between crore and other units including million, billion, lakh, and thousand.
What is the largest number that can be expressed in Indian numbering terminology?
The traditional Indian numbering system extends to shankh (10¹⁷) and beyond in classical texts, but modern usage rarely goes beyond crore for practical purposes. The [Indian Number Converter](/indian-number-converter/) covers up to quintillion (10¹⁸), which is sufficient for GDP figures, national budget discussions, and population estimates. For reference: India's GDP is approximately ₹300 lakh crore (₹3×10¹⁴), far beyond common conversational use of the number system.