About this tool
What does it convert?
Integers between bases: binary (2), octal (8), decimal (10), hexadecimal (16) and custom bases up to 64 — the daily bread of permissions, colors, encodings and protocol work.
How to use it
- Enter a number and its base, read all representations at once.
- Use for chmod bits, color codes and byte offsets.
- Batch-convert lists for tables and docs.
Examples
- chmod 755 → rwxr-xr-x: owner 7, group 5, other 5.
- Color #ff0000 → decimal 16711680.
- Offset 0x1F90 → 8080, the familiar HTTP-alt port.
Important limitations
- Integers only — fractions need fixed-point or decimal handling, not base tricks.
- Very large values exceed double precision; big-integer mode for crypto-sized numbers.
- Leading zeros and prefixes (0x, 0o) are notation, not value — strip or declare them.
Privacy
Local arithmetic. Nothing leaves your browser.
Frequently asked questions
Why is 10 “10” in every base?
“10” always means one-of-base — its value differs, its shape doesn’t.
Hex or decimal in code?
Hex for bit patterns and addresses, decimal for counts humans read.
Base64 the same thing?
Related idea (base-64 digits), different job: encoding bytes, not converting integers.