TASK

Detect the encoding of unknown text and decode it correctly

Take a string of mojibake or raw bytes, identify whether it is UTF-8, Latin-1, Base64, or URL-encoded, and decode it to readable text.

1

When text arrives from an unknown source it may be double-encoded, in a legacy charset, or wrapped in Base64. Guessing the encoding by eye is error-prone — use statistical detection first, then apply the matching decoder.
2

Encoding Detector →
Paste the raw text or hex. The tool reports the most likely charset (UTF-8, ISO-8859-1, Shift-JIS, etc.) with a confidence score.
3

Charset Reference →
Look up the detected charset to confirm its byte ranges and common use cases before committing to a decode.
4

Base64 Decoder →
If detection suggests Base64 (high ratio of [A-Za-z0-9+/=], length multiple of 4), decode here first, then re-run detection on the result.
5

URL Decoder →
If the text contains many %XX sequences, URL-decode first, then re-examine the output for a second encoding layer.

Frequently asked questions

The detector says UTF-8 but the text still looks wrong — what next?: The text may be double-encoded (e.g. UTF-8 bytes interpreted as Latin-1 then re-encoded). Try decoding as Latin-1 first, then re-encode the result as UTF-8, or look for a Base64/URL layer underneath.
How reliable is automatic detection?: Statistical detection is ~95% accurate for common charsets on sufficient text, but short strings or ambiguous byte patterns can fool it. Always sanity-check the decoded output against expected content.

Workflows that solve this

Base64 encode then decode round-trip

Encode text to Base64 and decode it back to verify the round-trip preserves the original data.

Convert Base64 to Base85

Decode Base64 and re-encode as Base85 for compact representation.

Convert Base64 to Hex

Decode a Base64 string into raw bytes and re-encode it as hexadecimal for inspection or interop.

Decode a Basic Auth credential pair

Decode the Base64 portion of an HTTP Basic Authorization header into username:password.

Decode and format a JWT payload

Parse a JWT token, extract its payload, and format the JSON for inspection.

Decode URL and show hex bytes

Percent-decode a URL-encoded string then view its hexadecimal byte representation for low-level analysis.

URL Decode and Parse

URL-decode then parse the URL into components.

URL double decode

Decode a URL-encoded string that has been encoded twice, recovering the original plaintext.

Decode nested URL parameter (Base64 JSON)

Unwrap a URL parameter that carries URL-encoded Base64 JSON into readable, formatted JSON.

Learn more

Want to understand why?

How to Detect Text Encoding

Identify the character encoding of a file or byte stream when the encoding is not declared.

How to Handle the Byte Order Mark (BOM)

Understand what a BOM is, when it helps, and when it causes problems in text processing.

ASCII (American Standard Code for Information Interchange) is a 7-bit character encoding standard that defines 128 characters (0-127), covering English letters, digits, punctuation, and control characters.

The BOM (byte order mark) is the Unicode character U+FEFF, placed at the start of a text stream to indicate the encoding form and byte order.

Related tools

Encoding Detector

Check text encoding: ASCII subset, UTF-8 BOM, and non-ASCII characters. Text input is always re-encoded as UTF-8, so legacy encodings (GBK/Big5/Shift-JIS) cannot be distinguished — the tool honestly reports the UTF-8 byte form. Free, private, 100% client-side.

Charset Reference

Reference table of character encodings. Free, private, 100% client-side.

Decode Base64 data back to readable text online. Free, private, and 100% client-side.

Decode percent-encoded URL text back to readable characters. Free, private, and 100% client-side.