Hex to Octal Converter

Convert base-16 integers directly to base 8 with no floating-point precision loss.

Hexadecimal input

Result

—Exact integer conversion. Spaces and underscores are accepted as visual separators.

Check the number representation

Keep number base, bit width, signedness and byte order explicit instead of letting one representation silently imply another.

ParseIdentify the input base or prefix before calculation.

RepresentCross-check binary, octal, decimal and hexadecimal views.

CalculateUse arithmetic or bitwise operations with exact integer scope.

Inspect bitsChoose width, signed interpretation, shifts and byte order explicitly.

Copy / verifyCopy only after checking the representation your code or protocol expects.

Base arithmetic Binary calc Hex calc Bitwise Shift Signed/unsigned Two’s complement IEEE-754 Endian

All developer-number calculations run locally. Fixed-width tools model integer bit patterns, not language-specific undefined behavior, CPU flags, binary protocol schemas or floating-point reinterpretation unless a dedicated tool says so.

Bidirectional base audit

Convert exact integers both ways and keep decimal plus grouped-binary evidence beside the result.

ModeInteger

—Converted result

—Decimal

—Binary

4-bit hex groups—3-bit octal groups—

Ready.

Representation is context

A hexadecimal or binary string does not automatically tell you whether a value is signed, how wide it is, whether bytes are little endian, or whether the bits represent an integer or floating-point value.

Use this result with confidence

Hex and octal are two groupings of the same bits

Hexadecimal groups binary digits four at a time while octal groups them three at a time. For exact integer conversion, expanding to one binary bit string and regrouping it is a useful independent check because the represented value never changes. Leading zero padding may be added only to complete a group and should not be mistaken for extra significant value.

Validate the input alphabet before converting

Hexadecimal accepts 0–9 and A–F, while octal accepts only 0–7. A digit such as 8 or 9 is therefore valid in decimal and hex but invalid in octal. Rejecting invalid digits early is safer than silently treating the text as another base. Prefixes such as 0x and 0o are notation conventions, not part of the underlying number.

Use integer arithmetic for long identifiers

Large register masks, file offsets, permissions, and protocol fields can exceed the exact integer range of ordinary JavaScript Number values. A BigInt conversion avoids floating-point rounding for whole numbers, so the hexadecimal, octal, decimal, and binary views remain exact. If a downstream system has a fixed bit width, apply that width separately rather than assuming arbitrary-precision output will fit.

Round-trip the representation before copying

A strong audit is to convert the result back to the original base and compare normalized digits. This catches grouping and transcription errors without relying on visual similarity. Keep decimal and grouped-binary evidence beside the final result when the converted value will be pasted into code, permissions, memory maps, or documentation where one wrong digit can change the meaning.