Octal to Hexadecimal

Convert octal numbers to hexadecimal. Bridge between Unix-style octal and modern hex notation used in programming.

What is the Octal to Hexadecimal Converter?

This tool converts octal numbers (base-8) to hexadecimal (base-16), bridging old and new computing notations.

How it works: the value is converted through binary or decimal as an intermediate step, since 8 = 2³ and 16 = 2⁴.

Why Convert Octal to Hex?

Modernizing Code

Update legacy octal literals to modern hex notation.

Cross-Referencing

Compare Unix-style and Windows-style documentation.

Learning

Understand how the bases relate through binary.

Debugging

Interpret output that mixes octal and hex values.

The Conversion Method

Octal to hex requires converting through binary or decimal as an intermediate step.

Example: 755 → 111101101 (binary) → 1ED (hex).

How to Use

Enter the Octal Number

Use the digits 0–7 only.

View the Hex Result

The hexadecimal value is converted automatically as you type.

Use in Modern Context

Add a 0x prefix for code, then copy the value.

Bidirectional: both fields are editable. Type a hexadecimal value in the result field to convert it back to octal, or use the swap button to flip the direction.

Common Permission Values

Octal	Hex	Decimal
400	`100`	256
644	`1A4`	420
755	`1ED`	493
777	`1FF`	511

Frequently Asked Questions

Can octal convert directly to hex?

Not digit by digit, because 8 and 16 do not align cleanly. The conversion passes through binary or decimal as an intermediate step.

Why is 755 equal to 1ED in hex?

755 in octal is 493 in decimal. In hex, 1ED = 1×256 + 14×16 + 13 = 256 + 224 + 13 = 493 (remember E=14, D=13).

When would I use this conversion?

It is useful when modernizing legacy code that uses octal literals, or when cross-referencing documentation that reports the same value in different bases.