Type a number in any base and the others update instantly. Supports binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Handles numbers up to 2⁵³.
Number Base Converter is a free, instant tool that translates a whole number between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) — type into any field and the other three update live.
Every base is both an input and an output here: there is no single result box, just four linked fields that stay in sync as you type. That makes it ideal whenever you need to see the same value in several notations at once. People reach for it to:
The converter handles values up to 2⁵³ − 1 and validates each field as you go, flagging an invalid digit (a 2 in a binary box, or a G in hex) instead of guessing. A copy button on every card grabs that one representation in a click.
Because the whole tool runs in your browser, nothing you type is ever uploaded. It also works offline once loaded, so you can keep a quick base-conversion scratchpad open while you work without sending a single number to a server.
Type your binary digits into the Binary field and the Decimal field updates instantly. Behind the scenes, each binary digit is multiplied by a power of two and the results are added together, so 1010 becomes 8 + 0 + 2 + 0, which equals 10.
Enter your hexadecimal value, with or without a leading 0x, into the Hexadecimal field. The decimal, binary, and octal fields all update at once. Hex uses digits 0 to 9 and letters A to F, where A equals 10 and F equals 15.
Hexadecimal is used for memory addresses, colour codes such as FF8800, file permissions, MAC addresses, and inspecting raw bytes. Because one hex digit maps to exactly four binary bits, it is a compact, readable shorthand for binary data.
Binary numbers get long and hard to read very quickly. Each hex digit represents four bits, so a single byte fits in two hex digits instead of eight binary ones. Hex keeps values short while staying easy to translate back to binary by hand.
Octal is base 8 and uses digits 0 to 7, grouping bits in threes. Hexadecimal is base 16 and uses 0 to 9 plus A to F, grouping bits in fours. Octal shows up in older systems and Unix file permissions, while hex dominates modern programming.
You can convert any whole number up to the JavaScript safe integer limit of 2⁵³ − 1 (9,007,199,254,740,991). For larger values, use a language with native BigInt support.
No. Every conversion runs locally in your browser and nothing is sent to a server. Once the page has loaded it also works offline, so your numbers stay completely private.