Subtitle Encoding Detector

Free browser tool · Nothing uploaded · Updated August 4, 2026

Find out what character encoding a subtitle file is actually in. Drop a file and it tells you the detected encoding and shows a decoded preview — useful for diagnosing garbled subtitles before converting. Read-only and 100% local; to convert to UTF-8, use the Encoding Fixer.

🔒 100% local. Your file is processed in your browser and never uploaded.
Drop your subtitle file here, or click to choose
.srt, .vtt, .ass, .ssa, .sub — read as raw bytes on your device.

How does encoding detection work?

The tool reads the file as raw bytes and first checks whether it is valid UTF-8. If not, it decodes the bytes with each likely encoding — GB18030, Big5, Shift_JIS, EUC-KR, Windows-1252 — and keeps the one that produces the most real characters and the fewest garbage symbols. It also recognizes double-encoded (mojibake) UTF-8, the kind where 你好 becomes ä½ å¥½.

I detected the encoding — how do I fix the file?

Detection is read-only. To actually convert the file to clean UTF-8, use the Subtitle Encoding Fixer, which uses the same detection and lets you download the converted file.

Frequently Asked Questions

What encodings can it detect?

UTF-8, GB18030 (Simplified Chinese), Big5 (Traditional Chinese), Shift_JIS (Japanese), EUC-KR (Korean), and Windows-1252 (Western), plus double-encoded UTF-8 mojibake.

Does it change my file?

No. The detector is read-only — it only tells you the encoding and shows a preview. Use the Encoding Fixer to convert.

Is my file uploaded?

No. It is read as bytes in your browser and never leaves your device.

See all free subtitle tools.

Working with subtitles at scale?

These free tools handle files you already have. GeekLink extracts hardcoded subtitles via OCR, transcribes and translates with AI, and burns subtitles into video — batch-processing dozens of videos, all locally on your Mac or Windows PC.

Try GeekLink Free