Overview
Check whether a piece of text is representable in strict 7-bit ASCII - the original 128-character set (code points 0-127) covering unaccented English letters, digits, and basic punctuation - and if it isn't, see exactly which character fails, at what position, and its actual Unicode code point, rather than getting a silently mangled or truncated result. This tool deliberately does not offer a "convert anyway" mode: there is no lossless way to turn "café" or "€" into ASCII, since ASCII has no representation for é or €, and the two common approaches for forcing the conversion - transliterating accented letters to their unaccented equivalent (café → cafe) or escaping non-ASCII characters as \uXXXX sequences - either silently discard information or produce something that is not actually ASCII text, just an escaped representation of the original. Both would risk giving false confidence that lossy or non-ASCII output is safe to treat as ASCII, so this tool only validates and reports, it never silently rewrites. This is a genuinely different check from text-ascii-converter, which converts text to/from Unicode code points of any size (including values well above 127) rather than validating ASCII-compatibility specifically. Useful for confirming a string is safe to write into a strict ASCII-only file format, protocol field, or legacy system before it reaches production and fails there instead. Runs entirely client-side.
Best for: Confirming a string is safe to write into a strict ASCII-only file format or legacy system before it fails in production
How to use this tool
- Paste your text. Any UTF-8 text - plain ASCII or text containing accented letters, symbols, or emoji.
- Every character is checked. Each character's Unicode code point is checked against the 0-127 ASCII range.
- See a pass or a precise failure. If everything is ASCII, the text is echoed back as valid. If not, every offending character is listed with its position and code point.
- Fix and recheck. Edit the flagged characters and the check re-runs instantly.
Why use this tool
Strict, honest validation
No transliteration or lossy "best effort" conversion mode - a character is either valid ASCII or it's clearly reported as not.
Exact failure location
Each non-ASCII character is shown with its character index and Unicode code point (hex and decimal), not just a generic "invalid" message.
Nothing silently dropped
Non-ASCII characters are never stripped, replaced, or escaped automatically - you always see exactly what would be lost.
Distinct from code-point conversion
Unlike text-ascii-converter, this specifically validates ASCII-compatibility rather than converting to arbitrary Unicode code points.
Frequently asked questions
Because there's no single correct way to do it. Stripping "café" to "caf" silently loses the last letter; transliterating it to "cafe" is a reasonable guess for one accented letter but wrong or ambiguous for many others (and outright impossible for symbols like "€", which has no ASCII equivalent at all). Silently guessing risks corrupting data without any indication it happened - this tool would rather clearly tell you what isn't ASCII so you can decide how to handle it yourself.
Strict 7-bit ASCII: Unicode code points 0 through 127, covering unaccented basic Latin letters (A-Z, a-z), digits (0-9), common punctuation, and control characters. Anything with a code point of 128 or higher - accented letters, symbols like "€" or "£", emoji, and most non-Latin scripts - is flagged as non-ASCII.
Text to ASCII Converter converts any text to its Unicode code points, including large ones well above 127 - it's a code-point converter, not an ASCII validator. This tool instead answers a narrower, specific question: is this text entirely within the original 128-character ASCII range, and if not, exactly which characters aren't?
Both are reported as non-ASCII characters, each with its own code point (e.g. "€" is U+20AC / decimal 8364). Neither is silently dropped or approximated - you see precisely what's outside the ASCII range.