How to Convert a Decimal Number to Binary, Hexadecimal, Octal and ASCII at Once
Learn how to read a decimal value as binary, hex, octal and its ASCII character, and how the converter handles negatives, decimals and out-of-range codes.
Number Base Converter
Introduction
Developers switch between number bases constantly when reading permissions, colour codes, bit masks and character tables. The Number Base Converter takes a single decimal input and shows its binary, hexadecimal, octal and ASCII equivalents side by side, each with its own copy button. Conversion happens in the browser as you type.
Step-by-Step Instructions
- Type a whole number in the Enter Decimal Number (Base-10) field.
- Read the Binary (Base-2) card for the bit pattern.
- Read the Hexadecimal (Base-16) card, which is shown in uppercase with a 0x prefix.
- Read the Octal (Base-8) card and the ASCII Character card.
- Click Copy Value under any card to copy that representation to the clipboard.
Key Use Cases
- File Permissions: Convert 493 to octal to confirm it maps to 755.
- Colour Channels: Convert 255 to hex to get 0xFF for a CSS colour component.
- Character Codes: Enter 65 to confirm the ASCII character is A.
Frequently Asked Questions
Can binary or hex be entered as the input?
No. The single input field accepts a decimal (base-10) number only, and the other three bases are derived from it. To go the other way, convert the value to decimal first.
What happens with negative numbers or decimals?
A negative number is converted with a leading minus sign in each base, for example -255 becomes -11111111 in binary. A value with a fractional part is truncated to its integer portion before conversion, so 3.7 is treated as 3.
Why does the ASCII card show N/A?
The ASCII card only displays printable characters, which are codes 32 to 126. Any value outside that range, including control characters below 32 and extended values above 126, shows N/A and the copy button for that card is disabled.