Decimal to Octal Converter

Convert decimal (base-10) numbers to octal (base-8) instantly

Enter a positive decimal number (e.g., 100)
Octal representation (read-only)
Conversion Result
100โ‚โ‚€ = 144โ‚ˆ
Decimal 100 equals Octal 144

Step-by-step Calculation:

๐Ÿ“š Decimal to Octal Conversion Details

What is Decimal?

Decimal (base-10) is our everyday number system using digits 0-9. Each position represents a power of 10.

What is Octal?

Octal (base-8) uses digits 0-7. Each position represents a power of 8. Commonly used in computing.

Conversion Method

Divide the decimal number by 8 repeatedly, keeping track of remainders. Read remainders in reverse order.

Common Uses

  • Computer programming
  • Unix file permissions
  • Digital electronics
  • Number system education

๐Ÿ“ How to Convert Decimal to Octal

Follow these steps to convert any decimal number to octal:

  1. Divide the decimal number by 8
  2. Record the remainder (0-7)
  3. Use the quotient as the new number
  4. Repeat until quotient is 0
  5. Read remainders in reverse order
// Example: Convert 100 to Octal
100 รท 8 = 12 remainder 4 โ† LSD
12 รท 8 = 1 remainder 4
1 รท 8 = 0 remainder 1 โ† MSD

// Read remainders from bottom to top:
// 100โ‚โ‚€ = 144โ‚ˆ

๐Ÿ“Š Conversion Table

Decimal Octal Calculation
8 10โ‚ˆ 8รท8=1R0, 1รท8=0R1
16 20โ‚ˆ 16รท8=2R0, 2รท8=0R2
32 40โ‚ˆ 32รท8=4R0, 4รท8=0R4
64 100โ‚ˆ 64รท8=8R0, 8รท8=1R0, 1รท8=0R1
100 144โ‚ˆ 100รท8=12R4, 12รท8=1R4, 1รท8=0R1
255 377โ‚ˆ 255รท8=31R7, 31รท8=3R7, 3รท8=0R3

โ“ Frequently Asked Questions

Q: What is the largest digit in octal system?

A: The largest digit in octal is 7. After 7 comes 10 (which represents 8 in decimal).

Q: Why is octal used in computing?

A: Octal was historically used because it's easier to convert to/from binary (3 bits = 1 octal digit).

Q: How do I convert octal back to decimal?

A: Multiply each digit by 8 raised to its position power, starting from right (8โฐ, 8ยน, 8ยฒ, etc.) and sum them.

Q: What's the difference between octal and hexadecimal?

A: Octal is base-8 (0-7), hexadecimal is base-16 (0-9, A-F). Hex is more compact for large numbers.