English | 中文
Translate subtitles effortlessly—fast, accurate, and multilingual!
Subtitle Translator is a free and open-source batch subtitle translation tool that supports .srt, .ass, and .vtt formats. With real-time translation speeds, it leverages multiple translation APIs and AI models to quickly translate subtitle files into 35 languages, including the ability to translate a single subtitle file into multiple languages at once for global accessibility.
Compared to traditional subtitle translation tools, Subtitle Translator excels with its batch processing, high-speed translation, translation caching, and automatic format adaptation, significantly improving workflow efficiency. It is ideal for use in film and TV, education, and content creation.
👉 Try it online: https://tools.newzone.top/en/subtitle-translator
- Real-time translation: Uses chunked compression and parallel processing to achieve 1-second translation per episode (GTX interface is slightly slower).
- Batch processing: Handles hundreds of subtitle files at once, significantly boosting efficiency.
- Translation caching: Automatically stores translation results locally, avoiding redundant API calls and saving both time and costs.
- Format compatibility: Automatically detects and adapts to
.srt,.ass, and.vttsubtitle formats, preserving the original file name. - Subtitle extraction: Allows easy text extraction for use in AI summarization, content repurposing, and more.
- Multiple translation options: Supports 3 free translation APIs, 3 commercial-grade APIs, and 5 AI LLM (large language model) interfaces, catering to different needs.
- Multi-language support & internationalization: Translates subtitles into 35 major languages, including English, Chinese, Japanese, Korean, French, German, and Spanish. It also supports multi-language translations from a single file, generating bilingual or multilingual subtitles.
Subtitle Translator offers a range of customizable parameters to meet diverse user needs. Below is a detailed explanation of its features.
Subtitle Translator supports 5 translation APIs and 5 AI LLM models, allowing users to choose the best option for their needs.
| API | Translation Quality | Stability | Best Use Case | Free Tier |
|---|---|---|---|---|
| DeepL (X) | ★★★★★ | ★★★★☆ | Best for long texts, fluent translations | 500,000 characters/month |
| Google Translate | ★★★★☆ | ★★★★★ | Best for UI text and common phrases | 500,000 characters/month |
| Azure Translate | ★★★★☆ | ★★★★★ | Best for multi-language support | 2 million characters/month (first 12 months) |
| GTX API (Free) | ★★★☆☆ | ★★★☆☆ | General translation tasks | Free |
| GTX Web (Free) | ★★★☆☆ | ★★☆☆☆ | Small-scale translations | Free |
- DeepL: Ideal for long-form content, offering more fluent translations, but requires local or server proxy usage.
- Google Translate: Stable and widely used, best for short sentences and UI text.
- Azure Translate: Supports the most languages, making it the best option for multi-language translations.
- GTX API/Web: Free translation options, suitable for light usage but with limited stability.
🔹 API Key Registration: Google Translate, Azure Translate, DeepL Translate
🔹 Supported Languages: DeepL, Google Translate, Azure
Subtitle Translator also supports 5 AI LLM models, including OpenAI, DeepSeek, Siliconflow, and Groq.
- Best for: Literary works, technical documents, and multilingual dialogue.
- Customization: Supports system prompts and user prompts, allowing personalized translation styles.
- Temperature control: Adjusts AI translation creativity, where higher values produce more diverse translations but may reduce consistency.
Subtitle Translator supports .srt, .ass, and .vtt formats with automatic format detection and adaptation:
- Bilingual subtitles: Translated text can be inserted below the original and its position can be adjusted.
- Timeline compatibility: Supports over 100-hour timestamps, along with 1-3 digit millisecond formats to ensure seamless synchronization.
- Automatic encoding detection: Prevents character encoding issues by detecting and adjusting encoding settings automatically.
Subtitle Translator offers batch translation and single-file translation, adapting to different workflows:
✅ Batch Translation (Default Mode)
- Processes hundreds of files simultaneously, maximizing efficiency.
- Translated files are automatically saved in the browser’s default download folder.
✅ Single-File Mode (For quick tasks)
- Allows direct text input and translation.
- Results are displayed instantly, with the option to copy or export.
- Uploading a new file will replace the previous file.
Subtitle Translator employs local caching to optimize efficiency:
- Caching rules: Translation results are stored using a unique key format:
original_text_target_language_source_language_API_model_settings - Efficiency boost: Avoids redundant translations, reducing API calls and speeding up workflows.
Subtitle Translator allows translating the same subtitle file into multiple languages at once, ideal for internationalization.
For example:
- Translate an English subtitle into Chinese, Japanese, German, and French simultaneously for global accessibility.
- Supports 35 major languages, with more to be added based on user feedback.
When using Subtitle Translator, keep in mind:
- DeepL API does not support web-based usage. Instead, Subtitle Translator provides a dedicated server-side proxy for DeepL translations, ensuring security and efficiency. Users can also deploy the proxy locally.
- Subtitle Translator does not store API keys—all data remains locally cached in your browser for privacy.
- GTX Web API runs locally to prevent server overload. Avoid using GTX Web in global proxy mode to prevent translation errors.
🚀 Upcoming Features:
✅ Standalone desktop version
✅ AI-powered translation refinement
Subtitle Translator will continue to evolve based on user feedback. If you find this tool helpful, feel free to contribute or suggest improvements! 🚀
Subtitle Translator can be deployed on Cloudflare, Vercel, or any server.
System Requirements:
- Node.js 18.18 or later.
- macOS, Windows (including WSL), and Linux are supported.
# Installation
yarn
# Local Development
yarn dev
# build and start
yarn build && yarn start
# Deploy for a single language
yarn build:lang en
yarn build:lang zh
yarn build:lang zh-hantOpen http://localhost:3000 with your browser to see the result.
You can start editing the page by modifying src/app/[locale]/page.tsx. The page auto-updates as you edit the file.