Why does the converter use BigInt instead of regular numbers?

JavaScript's standard Number type uses 64-bit IEEE 754 floating-point, which can only safely represent integers up to 2^53-1 (about 9 quadrillion). For cryptographic hashes, large memory addresses or 64-bit integers, values exceed this limit. BigInt supports arbitrary-precision integers, ensuring accurate conversion for any integer size.

What is the maximum number I can convert?

There is no hard limit. BigInt handles numbers of arbitrary size. However, for very large numbers (hundreds of bits), binary representation becomes extremely long and may be hard to read in the UI.

Developer Utilities

Number Base Converter

The problem: Developers, CS students and hardware engineers constantly need to translate numbers between decimal, binary, hex and octal representations — a mental exercise that wastes time.

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100% In-Browser Execution. Zero server uploads. Your data never leaves this tab — disconnect your internet and the tool keeps working.

ASG Privacy VerifiedVerified

100% In-Browser Execution. Zero server uploads. Your data never leaves this tab — disconnect your internet and the tool keeps working.

Enter a number (select input base below)

Decimal (Base 10)

255

Binary (Base 2)

11111111

Hexadecimal (Base 16)

Octal (Base 8)

377

Two's Complement (8-bit)

11111111

ASCII Character

—

Decimal value: 255

Quick Reference

Dec

Bin

Hex

Oct

100

101

110

111

1000

1001

1010

1011

1100

1101

1110

1111

Number Base Converter: the complete guide

A number base converter translates integers between the four numeral systems used in computing: decimal (base 10, human-readable), binary (base 2, CPU and memory representation), hexadecimal (base 16, memory addresses, color codes, bytecode), and octal (base 8, Unix file permissions, legacy systems). This tool also shows the two's complement representation for understanding how signed integers are stored in fixed-width registers, the ASCII character equivalent for values in the printable range, and a full 0-15 reference table.

When each base is used in real-world computing

Decimal is the base humans use for all everyday arithmetic. Binary is the base CPUs use internally — memory, registers, logic gates and network protocols all operate on bits. Hexadecimal is used everywhere binary data is displayed to humans: memory dump addresses (0x7FFFFFFF), color codes in CSS (#FF5733), byte representations in cryptographic hashes and file headers, and machine code disassembly. Octal appears primarily in Unix file permission masks (chmod 755 = binary 111 101 101) and some legacy network protocol fields.

Two's complement explained

Two's complement is how CPUs store signed integers in a fixed number of bits. For an 8-bit signed integer, values 0-127 are stored normally; negative numbers use the rule: flip all bits, then add 1. So -1 in 8-bit two's complement is 11111111. The advantage is that addition hardware works identically for both signed and unsigned numbers. This tool shows the two's complement representation using the minimum bit width needed for the value (8, 16, 32 or 64 bits).

Step by step: how to use Base Converter

1
Type a number in the input field in its native base.
2
Select the input base (Decimal, Binary, Hex, or Octal) using the buttons below the field.
3
All four representations update instantly in the results grid.
4
Click 'Use' on any result card to set that representation as the new input.
5
Review the two's complement bit pattern and ASCII character at the bottom.
6
Use the 0-15 reference table for quick lookup of common hex values.

Security & privacy

Number conversion is a pure mathematical operation performed entirely in your browser using JavaScript's BigInt type for arbitrary precision. No numbers are sent to any server. The tool works offline and is safe to use with sensitive values such as memory addresses, cryptographic key fragments or internal IDs.