Octal to Hex

Octal to Hex Converter

Convert octal numbers to hexadecimal in bulk. Paste a list with one octal value per line and get hex output instantly: 377 → FF, 755 → 1ED, 100644 → 81A4, 17777777777 → 7FFFFFFF. The reverse mode turns hex values into octal.

Octal to hex through binary

The simplest manual method uses binary as a bridge:

1. Write each octal digit as three bits: 755 → 111 101 101.
2. Regroup the bits into fours from the right: 1 1110 1101 → 0001 1110 1101.
3. Replace each group with a hex digit: 1 E D → 1ED.

You can also convert via decimal (755₈ = 493₁₀ = 1ED₁₆), but the binary route never needs division. The converter uses exact big-integer arithmetic, so it gets long octal values right – including the 11-digit octal numbers found in tar headers.

Where octal-to-hex conversion comes up

• File modes – stat and ls show octal modes like 100644, while debuggers, hex editors, and some APIs show the same st_mode as hex (0x81A4).
• Escape sequences – converting \033 (octal) to \x1B (hex) when porting strings between languages.
• Old documentation – PDP-era and mainframe manuals often list values in octal that modern tools expect in hex.

Options

Choose Uppercase for 1ED or lowercase for 1ed, add a Prefix (0x or 0o), Pad to full bytes (F → 0F), or Group digits for long values. Leading minus signs and fractions are supported.

Quick reference

• 10 (octal) = 8 (hex) – one eight.
• 20 = 10 – sixteen.
• 377 = FF – the largest byte value.
• 1000 = 200 – 512.
• 177777 = FFFF – the largest 16-bit value.

Every conversion is exact, no matter how many digits you paste, and all processing happens locally in your browser. For other bases, use the All Number Converter.