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Octal to Decimal Converter

Convert an octal (base 8) number to decimal by expanding powers of eight.

Number base converter

Converting from Octal (base 8) to Decimal (base 10).

Converted value

34

Steps

  1. Input (base 8): 42
  2. Convert via decimal: parse in base 8, then express in base 10.
  3. Result (base 10): 34

How it works

Each position multiplies the digit by 8^position and sums, analogous to decimal place value with base 8.

How to use Octal to Decimal Converter

  1. Enter octal digits only (0–7).
  2. Read decimal equivalent.
  3. Pair with decimal-to-octal and the full base converter.

Worked examples

Concrete numbers and cases you can check against the tool above.

Octal 644

6×64 + 4×8 + 4 = 420 decimal.

When to use Octal to Decimal Converter

Misreading octal as decimal causes permission bugs. Validate chmod values before applying scripts.

Common use cases

  • Confirm 755 octal equals 493 decimal in some API fields.
  • Grade school base-conversion practice.

Inputs and outputs

  • Octal strings without 8 or 9

Privacy

This tool runs entirely in your browser. Your data never leaves your device — nothing is uploaded to our servers.

Frequently asked questions

Is 9 allowed?
No — invalid in strict octal.
Leading zero?
In JavaScript-style literals, a leading 0 once meant octal; here you choose octal mode explicitly.
Negative octal?
Rare; tool may treat minus as sign on the decimal parse path.

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