Number Base Converter
Convert between binary, octal, decimal, hex
About Number Base Converter
Number base conversion is fundamental in computer science. Binary (base-2), octal (base-8), decimal (base-10), and hexadecimal (base-16) are commonly used in programming and digital systems.
What is Number Base Converter?
The Number Base Converter is a free online tool that converts numbers between any base from 2 to 36, including all the named systems programmers use daily: binary (base 2), ternary (base 3), octal (base 8), decimal (base 10), duodecimal (base 12), hexadecimal (base 16), Base32, and Base36. Beyond the quick-pick named bases, a custom "base N" selector lets you choose any radix between 2 and 36, so unusual systems like base 5 or base 20 are one click away. Number base conversion is fundamental in computer science, because computers store data in binary while programmers often read it as hex, and these systems appear everywhere from web color codes to memory addresses and file permissions. You enter a number, tell the tool its base, and every other base is calculated instantly. The tool is BigInt-safe, so even very large numbers convert without losing precision. A second Text / ASCII mode lets you encode any text into the binary, octal, decimal, or hexadecimal code points of each character, with a per-character breakdown. The conversion happens in real time as you type, with the source base highlighted, and the tool validates your input so you never submit an invalid digit.
How to use Number Base Converter?
Converting between bases happens instantly:
- 1 Type the number you want to convert into the input field. Make sure every digit is valid for the base you will select, or the tool will flag it.
- 2 Choose the input base from the dropdown. Pick a named base such as Binary, Octal, Decimal, Hexadecimal, Base32, or Base36, or choose "Custom base" and enter any radix from 2 to 36.
- 3 View every conversion at once. The number is shown across all the supported bases simultaneously, with the source base card highlighted, plus a dedicated result tile when you pick a custom base.
- 4 Switch to Text / ASCII mode to encode text into character code points. Choose binary, octal, decimal, or hexadecimal and see both the joined output and a per-character breakdown.
- 5 Copy any result you need. Conversions update in real time as you type, so there is no button to press and no waiting.
Why use this tool?
Programmers, computer science students, and electronics hobbyists work with multiple number bases every day, and converting them by hand is slow and error-prone. This tool removes the mental arithmetic and gives you every common base from one input, instantly and accurately, plus any custom radix from 2 to 36. Hexadecimal is especially common in web development, where colors like #FF5733 are written in hex, and in low-level work involving memory addresses. Base36 is handy for compact identifiers, and the Text / ASCII mode is perfect for understanding how characters map to bytes. Seeing many bases side by side also makes the relationships between number systems clearer, which is great for learning. Because the conversion is BigInt-safe, you can work with numbers far larger than a normal 64-bit integer without rounding errors. The tool runs entirely in your browser and is completely free with no account required.
Examples
Enter decimal 255 and read its hexadecimal FF, binary 11111111, and octal 377 at once, the building blocks of web colors such as #FF5733.
Choose "Custom base", enter 36, and convert decimal 255 into Base36 73 for compact short identifiers and URL slugs.
In Text / ASCII mode, type the letter A to see it as decimal 65, hexadecimal 0x41, and binary 1000001, with a per-character breakdown.
Frequently Asked Questions
Is the Number Base Converter free to use?
Yes. The tool is completely free with no signup, no limits, and no account required. You can convert as many numbers as you like.
Which bases does it support?
It converts any base from 2 to 36. Named quick options include binary (2), ternary (3), octal (8), decimal (10), duodecimal (12), hexadecimal (16), Base32, and Base36, and a custom selector covers every radix in between.
Can it handle very large numbers?
Yes. Conversions are BigInt-safe, so even numbers far larger than a standard 64-bit integer are converted exactly without losing precision.
What is Text / ASCII mode?
It encodes each character of your text into its code point, shown in binary, octal, decimal, or hexadecimal, along with a per-character breakdown so you can see how letters map to bytes.
What happens if I enter an invalid digit?
The tool validates your input against the selected base. Binary accepts only 0 and 1, hexadecimal accepts 0 to 9 and A to F, and a base 5 value accepts only 0 to 4, so any invalid digit is flagged.
Do I need to click a button to convert?
No. Conversions happen in real time as you type, and every result updates automatically.
Why is hexadecimal so widely used?
Hexadecimal is compact and maps neatly onto binary, which is why it appears in web color codes and memory addresses.
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