無料オンライン文字起こしツール
ファイルをアップロード、マイクで録音、またはURLを貼り付け。AIが数秒で文字起こしします。
100以上の言語
自動検出または手動選択。主要な言語すべてに対応。
話者検出
誰が何を言ったかを自動的に識別します。
クライアントサイド暗号化
ブラウザで文字起こしを暗号化。私たちでも読めません。
6つのエクスポート形式
TXT、SRT、VTT、DOCX、JSON、PDF。
使い方
1
アップロードまたは録音
音声/動画ファイルをアップロード、YouTubeや任意のプラットフォームのURLを貼り付け、またはマイクで録音。
2
AIが文字起こし
複数のAIモデルから選択。言語自動検出。話者ダイアライゼーションで誰が何を言ったか識別。
3
エクスポートして共有
TXT、SRT、VTT、DOCX、JSON、PDFとしてダウンロード。リンクで共有。AIで精度を向上。
よくある質問
transcription runs in your browser: paste a URL, upload a file, or record from your mic. STT.ai picks the AI model and returns the transcript in under 5 minutes. Export as TXT, SRT, VTT, DOCX, JSON, or PDF.
Yes — every visitor gets 600 free minutes/month on STT.ai, usable for transcription the same as any other workflow. Paid plans starting at $5/month unlock longer files, private transcripts, and priority queueing.
transcription runs on the same AI models as the rest of STT.ai — our best models reach 95-97% accuracy on clean speech (3-5% Word Error Rate on benchmarks). Switch models on the fly if the first pass is below your target.
transcription can run on any of STT.ai's 10+ models — STT.ai Enhanced (most accurate), Whisper Large V3 (99 languages), NVIDIA Canary (#1 WER on supported langs), Whisper Turbo (fast), Moonshine (lightweight), and more.
Yes. Every transcript exports as SRT or VTT — works with YouTube, Vimeo, TikTok, VLC, and every major video player. The burn-subtitles tool overlays them onto video as hardsubs.
Yes. Speaker diarization automatically labels each voice (Speaker 1, Speaker 2, ...) and you can rename them in the built-in editor. Works across all models and languages.
Most transcription jobs finish in under 5 minutes. A 1-hour audio file typically completes in 2-3 minutes with our fastest models. Speed depends on chosen model and current GPU load.
transcription accepts 20+ formats — MP3, WAV, M4A, FLAC, OGG, MP4, MKV, MOV, WebM, AVI, and more. Output to TXT, SRT, VTT, DOCX, JSON, or PDF.
Yes. Audio files submitted to transcription are processed and deleted by default. Pro plans add client-side encryption — even if STT.ai's database is breached, your transcripts are unreadable without your key. Data is never used for model training without explicit opt-in.
Yes. STT.ai offers a REST API with Python and Node.js SDKs, plus an MCP server for Claude and Cursor — all usable for transcription workflows. Free API tier includes 100 minutes/month.
Yes. Every transcript opens in the built-in editor where you can correct words, rename speakers, adjust timestamps, and add notes. All changes save automatically.
Every transcript gets a unique shareable URL. Export to DOCX or PDF for email. Pro plans add password-protected and permanent links — useful for client work.
STT.ai handles 1,300+ platforms including YouTube, Vimeo, TikTok, SoundCloud, Zoom, Google Meet, podcast hosts, and more. URL transcription works with publicly-available content only — DRM-protected sources can't be transcribed.