Number Base Conversion
Convert between decimal, binary, octal and hexadecimal, and turn text into its UTF-8 bytes — with exact arithmetic on values far larger than a calculator can hold.
Quick number base converter
Type in any one of the four boxes and the other three update as you type — no need to pick a direction first.
Hexadecimal output is upper case and byte output is space-separated, matching how each is written in code and in memory dumps.
Available Conversions
Select a specific conversion tool to get started
Decimal to Binary
Turn any decimal number into binary, with exact results well beyond the range where a normal calculator starts rounding.
Binary to Decimal
Convert a binary string into ordinary decimal, and see the weighted-sum method that lets you do it by hand.
Decimal to Hex
Convert decimal into hexadecimal for memory addresses, colour codes and permission masks, with no rounding at 64 bits.
Hex to Decimal
Turn a hexadecimal value into decimal — the everyday job of reading an address, a hash prefix or a colour channel.
Decimal to Octal
Convert decimal into octal, the base behind Unix file permissions such as chmod 755 and 644.
Octal to Decimal
Convert octal into decimal, including the permission triples that chmod and stat report as three octal digits.
Binary to Hex
Convert binary to hexadecimal by grouping the bits in fours — the fastest hand conversion in day-to-day debugging.
Text to Binary
Turn text into its binary bytes, following UTF-8 so accented letters, Chinese characters and emoji all work.
Binary to Text
Decode a binary byte string back into readable text, with an honest error when the bytes are not valid UTF-8.
Text to Hex
Convert text into hexadecimal bytes for packet captures, protocol debugging and percent-encoding work.
How to Use This Tool
Select Conversion Type
Choose the specific conversion you need from the list above
Enter Your Values
Input the value you want to convert in the designated field
Get Instant Results
View the converted result immediately with high accuracy