Number Base Converter
Convert a number between numeral systems online. Enter a value, choose its base, and see the binary, octal, decimal and hexadecimal forms at once, with support for any base from 2 to 36.
FreeOnline Tool
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How to Use
- Type the number you want to convert into the input box.
- Select the base of the number you entered (2, 8, 10, 16 or a custom base).
- The tool shows the value in every common base automatically.
- Click the copy button next to a base to copy that result.
Features
- Shows binary, octal, decimal and hexadecimal results side by side
- Accepts input and produces output in any base from 2 to 36
- Handles negative numbers and large values
- Converts in real time as you type
- Each base result can be copied individually with one click
Use Cases
Reading values while debugging
Convert memory addresses, bit masks and other hexadecimal values into decimal or binary to make sense of them during debugging.
Working out subnet masks
Convert the decimal form of an IP address and subnet mask to binary to see exactly where the network and host bits split.
Converting color values
Turn a CSS hex color such as #FF8800 into decimal RGB components, or go the other way while doing color math.
Teaching computing fundamentals
Demonstrate how binary, octal, decimal and hexadecimal relate to one another with live worked examples.
FAQ
How do I convert quickly between binary and hexadecimal?
Every 4 binary digits map to 1 hex digit (0000 = 0, 1111 = F), so you can group the digits by hand, or just type the binary value here and read the hexadecimal result directly.
Does the case of hexadecimal letters matter?
No, 0xAF and 0xaf are the same value. This tool always outputs uppercase letters, which matches most coding conventions.
Can it convert fractional numbers?
The tool is designed for integer base conversion. Fractions are trickier because they can repeat indefinitely in another base, so handle the integer and fractional parts separately.
Do I need to type the 0x prefix for hexadecimal?
No. Just enter the digits themselves, such as FF or 1A3B. The tool interprets the input according to the base you selected.