Skip to content
Collabs Tool
CalculatorsRuns in your browser

Number Base Converter (Binary, Octal, Hex)

Convert a number between binary, octal, decimal and hexadecimal.

Input
No upload needed — instant
Privacy
Nothing is uploaded
Cost
Free · no sign-up · no watermark

Loading tool…

The tool is loading its code on your device. This happens once and is cached for later visits.

Processed entirely on your device

Everything you type or paste is handled by JavaScript running in this tab. No request is sent, nothing is logged and nothing is stored. Close the page and it is gone.

Overview

About the Number Base Converter (Binary, Octal, Hex)

Convert a whole number between binary, octal, decimal and hexadecimal in one step, and see the same value written out in all four bases at once.

Number bases are just different ways to write the same quantity. Enter a value, tell the converter which base it is in, and it shows the equivalent in binary, octal, decimal and hexadecimal all at once.

Place value in any base

decimal 255 = 2·100 + 5·10 + 5·1
binary  11111111 = 128+64+32+16+8+4+2+1
hex     FF = 15·16 + 15·1

Every base works the same way — each digit is worth the digit times the base raised to its position.

Why hex and binary pair up

One hexadecimal digit covers exactly four binary bits, so FF is 11111111. That is why hex is the shorthand of choice for colours, memory addresses and byte values.

Private and instant

Conversions run locally in your browser using integer arithmetic — nothing is uploaded and no account is needed.

Step by step

How to use the Number Base Converter (Binary, Octal, Hex)

  1. Type a value and choose the base it is written in.

  2. Read the decimal equivalent as the headline.

  3. See the same number in binary, octal, decimal and hexadecimal in the table.

Why use it

Benefits and common use cases

What this tool is good for, and what it deliberately does not try to do.

All four bases at once

One entry shows the value in binary, octal, decimal and hexadecimal together, so you never convert in steps.

Flexible input

Hex letters can be upper or lower case and a leading 0x is ignored, matching how bases are written in code.

Validated per base

The input is checked against the selected base — a '2' in binary is rejected rather than silently misread.

Questions

Frequently asked questions

Short, honest answers about quality, limits and privacy.

What is a number base?

It is how many unique digits a system uses. Decimal (base 10) uses 0–9, binary (base 2) uses 0 and 1, octal (base 8) uses 0–7, and hexadecimal (base 16) uses 0–9 then A–F for 10–15.

Why do computers use binary and hex?

Hardware switches are naturally on/off, which is binary. Hexadecimal is a compact, human-friendly shorthand for binary, since one hex digit maps exactly to four bits.

How do I convert binary to decimal by hand?

Each bit is worth a power of two, doubling from right to left. So 11111111 = 128+64+32+16+8+4+2+1 = 255. The calculator does this instantly for any length.