Octal to Decimal Converter | Convert Octal to Decimal Numbers

Free online octal to decimal converter. Convert octal numbers to decimal with step-by-step explanations and instant results. Includes conversion tables and examples.

Octal to Decimal Converter

Input

FromTextBinaryHexadecimalDecimalOctal

ToTextBinaryHexadecimalDecimalOctal

Character EncodingUTF-8ASCIIUTF-16

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Understanding Octal Place Values

8³	8²	8¹	8⁰
512	64	8	1

Powers of 8

8⁰ = 1

8¹ = 8

8² = 64

8³ = 512

Detailed Examples

Octal: 377

Decimal: 255

(3 × 8²) + (7 × 8¹) + (7 × 8⁰) = 192 + 56 + 7 = 255

Octal: 123

Decimal: 83

(1 × 8²) + (2 × 8¹) + (3 × 8⁰) = 64 + 16 + 3 = 83

Octal: 10

Decimal: 8

(1 × 8¹) + (0 × 8⁰) = 8 + 0 = 8

Octal: 777

Decimal: 511

(7 × 8²) + (7 × 8¹) + (7 × 8⁰) = 448 + 56 + 7 = 511

Common Octal Values

Octal: 10

Decimal: 8

Octal: 20

Decimal: 16

Octal: 40

Decimal: 32

Octal: 100

Decimal: 64

Octal: 200

Decimal: 128

Octal: 400

Decimal: 256

How Octal to Decimal Conversion Works

Step-by-Step Process

1. Identify the position value of each digit (powers of 8)
2. Multiply each digit by its position value
3. Sum all products to get the decimal result

Converting "47"₈

4 in position 1: 4 × 8 = 32

7 in position 0: 7 × 1 = 7

Sum: 32 + 7 = 39₁₀

Important Tips

• Valid octal digits: 0-7 only
• Each position is 8 times the previous
• Right-most position value is 1

Practice Problems

Convert: 77₈

Answer: 63₁₀

Convert: 123₈

Answer: 83₁₀

Convert: 200₈

Answer: 128₁₀

Real-World Applications

Unix File Permissions

chmod 777 - Full permissions (read, write, execute)

chmod 644 - Standard file permissions

chmod 755 - Executable file permissions

Other Uses

• Legacy computing systems
• Assembly language programming
• Data representation

Related Conversions

Octal to Binary

Octal to Hex

Decimal to Octal

Binary to Octal