Octal to Decimal Converter

Convert octal numbers (base-8) to decimal numbers (base-10) using positional notation method

Only digits 0-7 are allowed

How to Convert Octal to Decimal

1

Write down the octal number

2

Assign powers of 8 to each digit, starting from the right (8⁰, 8¹, 8², ...)

3

Multiply each octal digit by its corresponding power of 8

4

Add up all the products to get the decimal equivalent

Example: Convert 123₈ to Decimal

1×8² + 2×8¹ + 3×8⁰

= 1×64 + 2×8 + 3×1

= 64 + 16 + 3

= 83₁₀

Octal Number System Basics

Property Value
Base 8
Digits 0, 1, 2, 3, 4, 5, 6, 7
Position Value ..., 8³, 8², 8¹, 8⁰
Max digit value 7

Common Octal to Decimal Conversions

7 7
10 8
77 63
100 64
777 511
1000 512

Unix File Permissions (Octal Notation)

755 rwxr-xr-x (read, write, execute for owner; read and execute for others)
644 rw-r--r-- (read and write for owner; read for others)
777 rwxrwxrwx (full permissions for everyone)

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