What happens with a character outside the ASCII range?

The tool reports an error naming the specific character and its code point, rather than silently truncating or misrepresenting it, since ASCII is strictly limited to code points 0-127.

How is this different from Convert a String to Decimal?

Convert a String to Decimal covers the full Unicode range with no restriction. This tool specifically validates that every character fits within the ASCII range and errors otherwise.

Are spaces and newlines converted too?

Yes. Every character inside the range is encoded, so a space becomes 32 and a newline becomes 10. That is why the token count often exceeds the number of visible characters.

String to ASCII Converter - Text to ASCII Codes Online

Overview

Introduction

ASCII is the original 128-character text encoding, still the safe common denominator across countless systems.

This tool converts text to ASCII codes and flags anything outside that range.

What Is String to ASCII Converter?

A converter that encodes each character as its decimal ASCII code, validating that every character actually falls within the ASCII range (0-127).

It runs entirely client-side as part of this site's String Tools collection, so nothing you paste is ever uploaded to a server.

How String to ASCII Converter Works

Each character's code point is checked against the 127 upper bound; any character exceeding it triggers an error naming the offending character.

The transformation happens synchronously in JavaScript the moment you type, with no network round trip involved.

When To Use String to ASCII Converter

Use it to verify text is pure ASCII before sending it to a system with strict ASCII-only requirements, and to see its ASCII codes.

It's a fast way to get the answer without opening a code editor, a REPL, or writing a one-off script just to check.

Often used alongside ASCII to String Converter and String to Decimal Converter.

Features

Advantages

Actively validates ASCII-only input rather than silently accepting out-of-range characters.
Clear error messages naming the specific offending character.
Names the specific offending character when validation fails, so a single stray non-ASCII character is easy to locate in a long input.

Limitations

Rejects the entire conversion if even one character is outside ASCII, rather than partially converting.
Emits decimal only, so hexadecimal or binary representations require one of the sibling converters instead.

Examples

Converting ASCII text

Input

Hi

Output

72 105

Both characters fall within the ASCII range and are converted successfully.

Best Practices & Notes

Best Practices

Use Convert a String to Decimal instead if you want to convert Unicode text without an ASCII-range restriction.
Strip diacritics first when converting names or European text, since accented letters fall outside the range and abort the whole conversion.
Reach for this deliberately when ASCII-only output is a hard requirement, and the Decimal converter when it is not.

Developer Notes

Unlike the shared radix-encoding helper used by the binary/octal/decimal/hex tools, this converter has its own dedicated implementation with an explicit range check per character, since the ASCII/non-ASCII validation is the tool's whole purpose.

String to ASCII Converter Use Cases

Verifying text is pure ASCII before sending it to a legacy system
Looking up ASCII codes for characters in a known-ASCII string
Validating user input against an ASCII-only requirement

Common Mistakes

Expecting non-ASCII characters (like emoji or accented letters) to convert instead of raising an error.
Pasting text containing a typographic apostrophe or dash from a word processor, which looks like ASCII on screen but is not.

Tips

Use Convert a String to Decimal if you need to handle full Unicode text without the ASCII restriction.
Because the whole conversion fails on a single bad character, it doubles as a quick check that a string is pure ASCII.

String to ASCII Converter