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ASCII Converter

Convert text to Binary, Hexadecimal, Base64, Decimal, ROT13, URL encoding, and HTML entities — all at once. Edit any box and click its Convert button to sync every other format from it.

Text (ASCII / ANSI)

Binary

Hexadecimal

BASE64

Decimal

ROT13

URL Encoded

HTML Entities

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What is ASCII?

ASCII (American Standard Code for Information Interchange) is a character encoding standard that assigns every letter, digit, and common symbol a numeric code between 0 and 127. That number is what a computer actually stores and processes — "A" is really just the number 65, "a" is 97, and a space is 32.

Because computers work in numbers rather than letters, the same character can be represented in several equivalent ways: as a decimal number, as hexadecimal, as raw binary digits, or wrapped in an encoding like Base64, URL percent-encoding, or HTML entities for safe transport through a particular system. This tool converts freely between all of them.

What is an ASCII Converter?

This tool shows the same text simultaneously in eight formats: plain text, Binary, Hexadecimal, Base64, Decimal, ROT13, URL Encoded, and HTML Entities. Every box is editable, and every box has its own "Convert" button.

Type into "Text (ASCII / ANSI)" and click its Convert button to fill in every other format at once. Or edit any other box directly — pasting a hex string into the Hexadecimal box and clicking its Convert button decodes that hex back to text and re-encodes it into all the other formats, including plain text. Any box can act as the source.

Why Use an ASCII Converter?

  • ✓Learning how text encoding works — seeing "Hello" become 72 101 108 108 111 in decimal or 48 65 6c 6c 6f in hex makes character encoding concrete instead of abstract.
  • ✓Debugging encoding issues — comparing binary, hex, and decimal side by side helps spot off-by-one errors or wrong byte values when working with low-level protocols or file formats.
  • ✓CTF challenges and puzzles — many beginner security challenges hide a flag behind one or more layers of Base64, hex, ROT13, or URL encoding; this tool decodes them in seconds.
  • ✓Quick one-off conversions — turning a short string into hex for a config file, or decoding a Base64 token pasted from an API response, without opening a terminal or writing code.
  • ✓Teaching and demonstrations — showing how the same message looks completely different once encoded is a common way to introduce encoding versus encryption.

Features of This Tool

●Eight simultaneous formats: Text, Binary, Hexadecimal, Base64, Decimal, ROT13, URL Encoded, and HTML Entities
●Any box can be the source of truth — edit it and click its own Convert button to update every other box from it
●Base64 encoding/decoding handles full Unicode text (UTF-8), not just plain ASCII
●HTML entity encoding escapes &, <, >, ", and ' as named entities and encodes non-ASCII characters as numeric entities
●URL encoding uses form-style percent-encoding (spaces become +)
●ROT13 is applied the same way in both directions, since ROT13 is its own inverse
●"Highlight Text" instantly selects a box's full contents, ready to copy manually
●One-click copy button on every box
●Clear error message when a box's content can't be decoded in its expected format
●Runs entirely in your browser — nothing you type is ever uploaded to a server

How to Use the ASCII Converter

  1. 1

    Enter your text

    Type or paste text into the "Text (ASCII / ANSI)" box, or click "Load Sample" in the sidebar to try a ready-made example.

  2. 2

    Convert from text

    Click the "Convert" button under the Text box. Binary, Hexadecimal, Base64, Decimal, ROT13, URL Encoded, and HTML Entities all update to match.

  3. 3

    Or start from any other format

    Paste a value directly into any other box — for example a hex string or a Base64 string — and click that box's own Convert button. It decodes back to plain text and re-encodes every box, including Text, from that.

  4. 4

    Copy or select a result

    Click the clipboard icon in a box's header to copy its contents, or click "Highlight Text" to select everything in that box for a manual copy.

  5. 5

    Start over

    Click "Clear All" in the sidebar to empty every box and begin again.

Common Pitfalls

Editing a box without clicking its Convert button

Typing into a box only updates that one box — the others stay as they were until you click that box's own Convert button to propagate the change.

Extra or missing spaces in Binary, Hex, or Decimal

These three formats expect each byte separated by whitespace (e.g. "48 65 6c 6c 6f"). Removing the spaces, or running values together, causes the Convert button to fail with a decode error.

Mixing up which box is the source

If you edit Text and then click Convert on a different, still-stale box by mistake, that stale box overwrites your new Text edit. Always click Convert on the box you just changed.

Non-ASCII characters in Binary/Hex/Decimal round-trips

These three formats represent each character as its UTF-16 code unit. Characters outside the Basic Multilingual Plane (rare emoji, for example) may not round-trip perfectly through Binary/Hex/Decimal, even though Base64, URL Encoded, and HTML Entities handle them correctly.

Invalid Base64 padding

Base64 strings must be correctly padded with = characters to a multiple of 4. A truncated or manually edited Base64 value often fails to decode — copy the full value rather than editing it by hand.

Conversion Examples

Text to Hexadecimal

Each character becomes its two-digit hex byte value, separated by spaces.

Input

Hi!

Output

48 69 21

Text to Base64

The UTF-8 bytes of the text are encoded as a Base64 string.

Input

Hello

Output

SGVsbG8=

Text to ROT13

Every letter is shifted 13 places through the alphabet; numbers and punctuation are left untouched.

Input

Hello, World!

Output

Uryyb, Jbeyq!

Frequently Asked Questions

Is my text uploaded anywhere?▾

No. Every conversion runs locally in your browser using standard JavaScript encoding functions. Nothing is sent to a server.

Can I start from Base64 or Hex instead of plain text?▾

Yes. Paste your value into any box and click that box's own "Convert" button — it decodes back to plain text first, then re-encodes every other box (including Text) from that.

What format do Binary, Hex, and Decimal use?▾

Each character's numeric code is shown separately, separated by spaces — for example "H" becomes "01001000" in binary, "48" in hex, or "72" in decimal. Multiple characters are joined with spaces between each value.

Is ROT13 secure encryption?▾

No — ROT13 is a simple substitution cipher used mainly to obscure spoilers or puzzle answers, not for real security. It provides no meaningful protection and is trivially reversible.

Does the URL Encoded box use %20 or + for spaces?▾

This tool uses form-style encoding, where spaces become +, matching the application/x-www-form-urlencoded format used by HTML form submissions.

Does HTML Entities handle emoji and non-English text?▾

Yes. Characters outside the standard ASCII range are converted to numeric HTML entities (like &#128512; for an emoji), which any browser or HTML parser can render correctly.

Why did Convert show a decode error?▾

It means the content in that box isn't valid for its format — for example, Hex with an odd number of characters, or a Base64 string with broken padding. Fix the value and click Convert again.