Why does it reject digits like 8 and 9 in octal?

Octal (base 8) only uses digits 0–7 — 8 and 9 aren't valid octal digits, so input containing them is rejected with a specific error rather than silently reinterpreted.

Does this share logic with the Binary Converter?

Yes — both tools use the exact same BigInt-based conversion engine, just with a different field order. There's only one conversion implementation to keep correct.

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Octal Converter

Convert a value between octal, binary, decimal, and hexadecimal — edit any one and the others update to match. Uses the same BigInt-based conversion engine as Binary Converter, so large integers convert exactly with no precision loss.

Edit any field — the others update to match

Octal (OCT, base 8)

Binary (BIN, base 2)

Decimal (DEC, base 10)

Hexadecimal (HEX, base 16)

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Binary ConverterConvert between binary, octal, decimal, and hexadecimal.Roman Numeral ConverterConvert between numbers and Roman numerals, in both directions.

Features

Converts between octal, binary, decimal, and hexadecimal at once
BigInt precision — no loss for large integers
Strict per-base digit validation

How to use

Edit any of the four fields.
The other three update automatically.

FAQ

Why does it reject digits like 8 and 9 in octal?: Octal (base 8) only uses digits 0–7 — 8 and 9 aren't valid octal digits, so input containing them is rejected with a specific error rather than silently reinterpreted.
Does this share logic with the Binary Converter?: Yes — both tools use the exact same BigInt-based conversion engine, just with a different field order. There's only one conversion implementation to keep correct.

Octal Converter

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Features

How to use

FAQ