🔁 Decimal ↔ Octal Converter
Translate decimal numbers to octal and octal back to decimal with binary equivalents.
Enter a decimal or octal number. The converter shows both directions and includes binary representations for deeper insight.
Supports negative integers. Decimals are not handled.
Use digits 0-7. Negative sign is allowed.
From Decimal
Octal: 377
Binary: 11111111
From Octal
Decimal: 255
Binary: 11111111
How to Use This Calculator
Enter decimal or octal
Type the number in the base you have. The converter updates the other base and binary output.
Review conversions
Observe decimal ↔ octal conversions plus binary to validate bit-level representations.
Copy results
Use the converted values in legacy systems, permissions settings, or academic exercises.
Formula
Octal digit value = Σ (digit × 8^position)
Decimal to octal uses repeated division by 8
Binary references use base 2 positional notation
Use the formula breakdown to confirm the calculation logic or perform the conversion manually if needed.
Full Description
Octal provides a convenient shorthand for groups of three binary digits, commonly used in historical computing, Unix file permissions, and assembly language. This converter keeps decimal, octal, and binary values aligned.
Having both directions displayed simultaneously helps confirm manual calculations and catch transcription errors.
Negative inputs are supported, mirroring how signed integers are handled in many programming languages.
Frequently Asked Questions
Can it convert fractions?
No. This tool focuses on integer conversions. Fractional octal conversions require additional steps.
Are spaces or underscores allowed in octal inputs?
No. Remove separators before converting. The input should be a continuous octal string.
What about very large numbers?
As long as the number stays within JavaScript’s safe integer range, conversions remain accurate.
Does it handle leading zeros?
Yes. Leading zeros are ignored in the conversion but displayed if present in the input.