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Number Base Converter

Convert numbers between bases 2 to 36 (binary, octal, decimal, hex and more).

Updated

This tool runs in your browser. No account or signup is required.

Common Number Base Converter tasks

Developers typically reach for this page when they need to convert between binary decimal octal and hex; convert numbers between bases 2 and 36; convert hex to decimal and binary. The tool is built for quick, practical work rather than a generic demo.

What matters in a number base converter workflow

When developers compare online tools for this job, the useful capabilities tend to center on bases 2–36, large integers, prefixes, multiple outputs. This page keeps those practical needs in mind while linking to related tools when a different workflow is a better fit.

What is Number Base Converter?

Number Base Converter converts a whole number from one base to another using the From and To base selectors. Letters in the result are uppercase.

What problem does it solve?

Bit masks, memory addresses, color codes and permissions all show up in different bases, and converting by hand is slow and error-prone.

How to use Number Base Converter

  1. Set the From and To bases.
  2. Type your number.
  3. Copy the converted value.

Example

Input

255 (from base 10 to base 16)

Output

FF

What you can do with Number Base Converter

  • Number base converter
  • Convert between binary, decimal and hex
  • Base 10 to base 16

Common use cases

  • Reading bit flags and masks
  • Converting hex values from a debugger or a spec
  • Learning how number bases relate

Related developer tasks

  • Number base converter
  • Convert between binary, decimal and hex
  • Base 10 to base 16

Converting between binary, octal, decimal and hex

  • Choose the From base and the To base from Binary (2), Octal (8), Decimal (10) or Hex (16).
  • Type a whole number. Hex digits are accepted in upper or lower case, and the result is uppercase.
  • Fractions are not supported and anything after a decimal point is ignored.
  • Very large integers lose precision beyond what JavaScript numbers can hold exactly.

Number base examples

1010   (2 -> 10)   =  10
255    (10 -> 16)  =  FF
FF     (16 -> 2)   =  11111111
17     (8 -> 10)   =  15

Focused conversions: Binary to Decimal, Decimal to Binary, Hex to Decimal, Decimal to Hex

Number Base Converter FAQ

What if I see "Invalid number for base"?

The input has a character that does not exist in the From base, for example a 2 in a binary number.

Are fractions supported?

The tool works on whole numbers. Anything after a decimal point is ignored.

Which bases are supported?

Binary (2), octal (8), decimal (10) and hexadecimal (16).

Looking for something else? Browse all developer tools.

onlinedevelopertool.com is a collection of 54 free, browser-based utilities for the small jobs that interrupt real work: formatting a JSON response, decoding a token, converting a timestamp, generating a UUID or checking a hash. Each tool has its own page with a short explanation, a worked example and answers to common questions, so you can use it and learn what it does at the same time.

There is no account to create and nothing to install. Tools run in your browser, so the text you paste is processed on your own device. The one exception is the Website Status Checker, which sends a request from your browser to the address you enter.

Three steps: paste your input, click the tool, copy the result, all inside your browser
Popular developer utilities: JWT decoder, UUID generator, Base64 decoder, SHA-256 hash, regex tester and timestamp converter

What you can do here

  • JSON Tools

    Format, validate, beautify and minify JSON, generate C#, TypeScript, Java, Python, Go, PHP and Kotlin models from it, or convert between JSON, YAML and CSV.

  • Encoders & Decoders

    URL, Base64 and HTML encoding and decoding, plus a JWT decoder for reading token claims.

  • Generators & Hashes

    Generate UUIDs and JWTs, validate UUIDs, and create MD5, SHA-256 and SHA-512 hashes.

  • Web Tools

    Timestamps, color codes, query strings and cron expressions - the small things web work keeps throwing at you.

  • Text & Data

    Format XML and YAML, count text, change case, make slugs, test regex, diff two texts and convert number bases.

  • Website Checking

    Check whether a website or URL is reachable from your browser.

Quick developer reference

  • JSON

    Keys and strings must use double quotes, and trailing commas and comments are not allowed. Those are the three most common reasons a payload fails to parse.

    Validate JSON

  • JWT

    A JSON Web Token is three Base64URL parts joined by dots: header, payload and signature. Decoding shows the claims but does not prove the token is genuine; only signature verification does.

    Decode a JWT

  • Base64

    Base64 is an encoding, not encryption. Anyone can reverse it, and it makes data roughly one third larger, so never use it to hide secrets.

    Decode Base64

  • UUID

    A version 4 UUID is made of random bits and written as 8-4-4-4-12 hexadecimal characters. Collisions are astronomically unlikely, which is why they work well as identifiers.

    Generate a UUID

  • Timestamps

    A Unix timestamp counts time since 1 January 1970 UTC. Ten digits usually means seconds and thirteen digits usually means milliseconds.

    Convert a timestamp

  • Hashes

    MD5 is fine for quick checksums but is not safe for security. Prefer SHA-256 or SHA-512, and remember that hashing is one-way and is not encryption.

    Create a SHA-256 hash

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