Is my subtitle file uploaded anywhere?

No. Your subtitle file is checked and repaired directly in your browser. It is not uploaded to Stay Local Tools servers for processing.

What is CPS and why does it matter?

CPS stands for characters per second — how fast a viewer needs to read a subtitle. It is calculated from the visible text and how long the subtitle stays on screen. There is no single correct number for every video, so this is a practical warning with an adjustable threshold, not a hard rule.

Does overlapping timing mean the file is broken?

Not always — some players handle overlapping subtitles fine, and it is sometimes done on purpose for multiple speakers. It is flagged as a warning so you can decide whether it matters for your use.

Subtitle Validator

Check subtitle files for timing errors, overlaps and other common problems.

Local Processing

Files stay on your device.

Choose File

or drag and drop files here

Supported: .srt, .smi, .sami, .vtt

Files stay on your device

Private by design

Your files are processed directly in your browser. They are not uploaded to Stay Local Tools servers for processing. Because the work happens on your device, your files stay with you unless you download or share them yourself.

Note: the website itself still loads normal web files, and may use analytics or ads later. The promise here is about the files and text you put into these tools.

How to Use

Choose your subtitle file (SRT, SMI or VTT).
Click Validate.
Review the errors and warnings, filtered by All, Errors or Warnings.
Click Repair Safe Issues to fix common problems automatically.
Download the repaired file.

Common subtitle errors

Subtitle files often pick up small problems over time: an end time that comes before the start time, a subtitle with no text at all, two subtitles that show at the same moment with overlapping timing, or index numbers that are missing, repeated, or out of order. This tool checks a file for all of these and more.

Overlaps and reading speed

Overlapping cues can look fine in some players and broken in others, so they are worth knowing about even though they do not always stop a file from working. Reading speed (characters per second, or CPS) is a practical guide for whether viewers have enough time to read a line — it is a helpful warning, not a strict rule.

What Repair Safe Issues changes

This button only applies fixes that are safe and unambiguous: renumbering, removing empty cues, trimming stray whitespace, clamping a negative start time to zero, and swapping a start/end pair that is clearly reversed. It never guesses at subjective quality issues like reading speed.

Questions and Answers

: No. Your subtitle file is checked and repaired directly in your browser. It is not uploaded to Stay Local Tools servers for processing.
: It only applies fixes that are safe and unambiguous: renumbering cues, removing empty subtitles, trimming stray whitespace, clamping a negative start time to zero, and swapping a start/end pair that is clearly reversed. It never guesses at subjective issues like reading speed.
: CPS stands for characters per second — how fast a viewer needs to read a subtitle. It is calculated from the visible text and how long the subtitle stays on screen. There is no single correct number for every video, so this is a practical warning with an adjustable threshold, not a hard rule.
: Not always — some players handle overlapping subtitles fine, and it is sometimes done on purpose for multiple speakers. It is flagged as a warning so you can decide whether it matters for your use.

Other Languages

Español

Validar subtítulos

Revisa archivos de subtítulos en busca de errores de tiempo, solapamientos y otros problemas comunes, y repara los seguros automáticamente. El archivo se procesa directamente en tu navegador y no se sube a los servidores de Stay Local Tools para el procesamiento.

Preguntas frecuentes

: No. Tu archivo de subtítulos se revisa y se repara directamente en tu navegador; no se sube a los servidores de Stay Local Tools.
: Solo aplica correcciones seguras e inequívocas: renumerar, quitar subtítulos vacíos, recortar espacios sobrantes, ajustar un tiempo negativo a cero e intercambiar un inicio/fin claramente invertido.
: CPS son los caracteres por segundo, es decir, la velocidad de lectura necesaria. Es una guía práctica, no una regla fija.

Português (Brasil)

Validar legendas

Verifique arquivos de legenda em busca de erros de tempo, sobreposições e outros problemas comuns, e conserte os seguros automaticamente. O arquivo é processado diretamente no navegador e não é enviado aos servidores do Stay Local Tools para processamento.

Perguntas frequentes

: Não. Seu arquivo de legenda é verificado e reparado diretamente no navegador; ele não é enviado aos servidores do Stay Local Tools.
: Ele só aplica correções seguras e claras: renumerar, remover legendas vazias, cortar espaços extras, ajustar um tempo negativo para zero e trocar um início/fim claramente invertido.
: CPS são os caracteres por segundo, ou seja, a velocidade de leitura necessária. É um guia prático, não uma regra fixa.

한국어

자막 오류 검사

자막 파일의 타이밍 오류, 겹침, 기타 흔한 문제를 검사하고 안전한 항목은 자동으로 복구할 수 있습니다. 파일은 브라우저에서 직접 처리되며 Stay Local Tools 서버에 업로드되지 않습니다.

자주 묻는 질문

: 아니요. 자막 파일은 브라우저에서 직접 검사하고 복구하며 Stay Local Tools 서버에는 업로드되지 않습니다.
: 번호 재정렬, 빈 자막 제거, 불필요한 공백 정리, 음수 시작 시간을 0으로 조정, 명백히 뒤바뀐 시작/끝 시간 교체 등 안전하고 명확한 수정만 적용합니다.
: 초당 글자 수(CPS)는 시청자가 자막을 읽는 데 필요한 속도를 뜻합니다. 절대적인 규칙이 아니라 실용적인 참고 기준입니다.