Decimal to Octal
Convert decimal numbers to octal — base 10 into base 8, any size.
How to use Decimal to Octal
- Enter a decimal number — e.g. 493. Several space-separated numbers convert together.
- Read the octal instantly: 493 → 755.
- Check the error line if a token isn't a plain number — it is named exactly.
- Click “Copy result” — add a 0o prefix if your programming language needs one.
What is Decimal to Octal?
A decimal to octal converter rewrites a base-10 number in base 8, where only digits 0–7 exist and places are worth 1, 8, 64, 512… Decimal 493 becomes octal 755, and decimal 64 becomes a round 100.
The manual method is repeated division by 8, reading remainders in reverse: 493 ÷ 8 = 61 r 5, 61 ÷ 8 = 7 r 5, 7 ÷ 8 = 0 r 7 → 755. This tool does that instantly and exactly, for numbers far beyond calculator range.
About the Decimal to Octal
Type a decimal number and its octal form appears instantly; space-separated numbers convert independently.
Where you'd want it: converting a file mode stored as a plain integer back into familiar chmod notation (420 → 644, 511 → 777), producing octal escape sequences (65 → 101, so the letter A is \101), converting values for retrocomputing or PDP-era formats, and checking number-systems homework. BigInt arithmetic keeps arbitrarily large numbers exact.
Everything runs in your browser with invalid input flagged by token. Octal to Decimal is the reverse tool; Decimal to Binary and Decimal to Hex cover the other common target bases.