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Binary, Decimal and Hex Converter

Convert a number between binary, decimal, hexadecimal and octal. Edit any field and the rest update instantly, all in your browser.

Runs entirely in your browser. Nothing you type is uploaded.
Decimal (base 10)
Hexadecimal (base 16)
Octal (base 8)
Binary (base 2)

Same number, four different bases

A number is just a quantity. The base is only how we write it down. Decimal (base 10) is what we count with, binary (base 2) is what computers store, hexadecimal (base 16) is the compact shorthand you see in color codes and memory addresses, and octal (base 8) still shows up in file permissions. This number base converter keeps all four in sync: type into any field and the others rewrite the same value instantly, with a gentle warning if a character does not belong in that base.

Keep the value you just converted

That hex you decoded for a bitmask or a color is exactly the kind of thing you copy once and need again later. Relic is an encrypted, permanent memory for everything you copy, so the value, the conversion, and that one constant stay searchable on every device, forever, end-to-end encrypted so only you can read them. The converter is free. Never re-deriving the same number twice is the upgrade.

Frequently asked questions

How do I convert between binary, decimal, hex, and octal?

Type a value into any one of the four fields (decimal, hexadecimal, octal, or binary) and the other three rewrite themselves to match instantly. There's no convert button and no direction to choose: every field stays in sync with whichever one you're editing.

Can it handle very large numbers?

Yes. It parses each value with JavaScript's BigInt, so there's no fixed maximum the way there would be with normal fixed-width integers. You can convert numbers far beyond 32 or 64 bits without losing precision.

What do these bases actually mean?

A number is just a quantity; the base is only how you write it down. Decimal (base 10) is everyday counting, binary (base 2) is what computers store, hexadecimal (base 16) is the compact shorthand in color codes and memory addresses, and octal (base 8) still shows up in Unix file permissions.

What happens if I type an invalid character?

The tool keeps your keystrokes visible in that field, outlines it in red, and shows a short "not a valid value" note, while leaving the other fields untouched. So a stray letter in the binary box (which only allows 0 and 1) is caught right where you typed it.

Is a hex value common enough to look up like this?

Very. Hex turns up in CSS color codes (like ff for full red), memory addresses, bitmasks, and hash output, and it maps cleanly to binary because each hex digit is exactly four bits. Converting it to decimal or binary is a routine part of reading that data.

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