Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal bases.
What is the Number Base Converter?
The Number Base Converter converts a number between binary, octal, decimal, and hexadecimal at the same time. Type a value into any one of the four bases and the tool instantly shows the equivalent value in the other three.
Switching between number systems is a routine task in low-level programming, debugging, and working with colors or memory addresses. Instead of doing the math by hand or running shell commands, this tool gives you all four representations in one view.
It is free and runs entirely in your browser. There is no signup and no data is sent to a server, so you can convert values quickly without leaving the page.
How to use the Number Base Converter
- 1Choose the base you want to type in by selecting the Decimal, Binary, Octal, or Hexadecimal tab.
- 2Enter your number in the input field for that base.
- 3Read the converted values in the summary cards showing Decimal, Binary, Octal, and Hexadecimal.
- 4Use the preset buttons to load common example values like 255 or 1024.
- 5Press Ctrl+L to reset all fields back to the default value of 255.
What you can use it for
- Converting a decimal RGB component to its two-digit hexadecimal form for a CSS color.
- Reading a hex memory address from a debugger and finding its decimal equivalent.
- Translating Unix file permission values between octal and binary.
- Checking the binary representation of a number while working with bitmasks or flags.
- Verifying ASCII character codes by converting between decimal and hexadecimal.
Key features
- Four-way conversion that updates decimal, binary, octal, and hex from a single input.
- Per-base input filtering that blocks characters not valid for binary, octal, or hex.
- Preset values for common cases such as a byte (255) and a kilobyte (1024).
- A Ctrl+L keyboard shortcut to clear all fields at once.
Frequently asked questions
How do I convert decimal to hexadecimal?
Open the Decimal tab, type your number, and the Hexadecimal value appears immediately in the results card. For example, entering 255 produces FF in hexadecimal.
Is the Number Base Converter free to use?
Yes, it is free with no signup. The conversion runs in your browser, so there are no limits on how many numbers you can convert.
Can it convert binary to decimal?
Yes. Select the Binary tab and enter a sequence of 0s and 1s. The tool shows the decimal value along with the octal and hexadecimal equivalents at the same time.
Does the converter support negative numbers?
It is designed for non-negative whole numbers. The binary, octal, and hexadecimal inputs only accept digits valid for those bases, so negative or fractional values are not supported.
Why does the hexadecimal result show a 0x prefix?
The results card displays hexadecimal with a 0x prefix to make it clear the value is in base 16, which is a common notation in code. The hexadecimal input tab itself accepts the digits without the prefix.
Is my input sent anywhere?
No. All conversions happen locally in your browser using built-in JavaScript number parsing. Nothing is transmitted to a server.