How to Transcribe Audio to Text Online — Free, No Upload (2026)
Transcription services that run on servers charge by the minute, require an account, and send your audio through their infrastructure. This guide walks through transcribing audio and video files using OpenAI Whisper running directly in your browser — the same model that powers many paid transcription services, available for free with no upload required.
Published August 2026 · SimpleTool Team
Output formats
Every transcription produces four download options — choose the one that fits your workflow:
After transcription, click any line in the transcript to jump to that moment in the built-in audio player — useful for reviewing and correcting errors in context.
Step-by-step guide
Open the Transcribe Audio tool
Go to simpletool.co/transcribe-audio. On first visit, the Whisper model (75 MB for Base, larger for Small) downloads from the CDN and caches in your browser. This one-time download takes 30–60 seconds on a fast connection.
Drop your audio or video file
Drag and drop an MP3, WAV, M4A, OGG, FLAC, MP4, WebM, or MOV file. Video files are automatically stripped to audio in the browser before transcription — no conversion step required.
Choose your model and language
Select Base (faster) or Small (more accurate). Language detection is automatic, but you can pin a language manually if needed. For most English or major-language recordings, auto-detect is accurate.
Wait for transcription
Transcription runs chunk-by-chunk in a background Web Worker so the browser tab stays responsive. A progress bar tracks each 30-second segment. On a modern laptop with WebGPU support, a 10-minute recording finishes in under 2 minutes.
Download your transcript
Click any transcript line to jump to that moment in the audio player. Then download in your format: TXT (plain text), SRT (subtitles with timestamps), Markdown (timestamp-embedded, Notion and Obsidian compatible), or JSON (word-level timestamps for programmatic use).
Ready to transcribe your audio or video file?
Open Audio Transcriber →About the Whisper model
This tool uses OpenAI Whisper, a speech-recognition model trained on 680,000 hours of multilingual audio. Whisper is the model behind most high-accuracy transcription APIs and services — here it runs as an ONNX model via Transformers.js inside a browser Web Worker.
On Chrome with a compatible GPU, WebGPU acceleration runs the model at near-realtime speed. On Firefox or older hardware, a WASM CPU fallback handles it — slower but equally accurate. The model processes audio in 30-second chunks with 5-second overlap, stitching the results into a continuous transcript with paragraph breaks inferred from silence gaps longer than 1.5 seconds.
The Base model (~75 MB) downloads once and caches in browser storage. On repeat visits it loads from disk in seconds — no re-download. If you need higher accuracy on difficult recordings, switch to the Small model at the cost of a slightly longer wait.
Tips for better transcription accuracy
Best results
- ✓Single speaker, minimal background noise
- ✓Studio or headset recording (not phone speaker)
- ✓Clearly paced speech, minimal crosstalk
- ✓Clean MP3, WAV, or M4A at standard bitrate
Expect more errors on
- ·Conference calls with echo and background noise
- ·Strong regional accents on rare languages
- ·Multiple overlapping speakers (no diarization)
- ·Technical jargon, proper nouns, brand names
The interactive transcript player lets you click any line to hear the corresponding audio — this makes it fast to find and correct errors without listening through the entire recording.
Why local transcription matters for sensitive recordings
Most transcription APIs send your audio to cloud servers for processing. For public content — podcasts, interviews, YouTube videos — this is generally fine. But for anything confidential — legal calls, medical consultations, private interviews, business meetings — routing audio through a third-party server creates a real exposure point.
With browser-based Whisper, the audio stays in your browser tab from drop to download. Nothing is transmitted. There are no logs, no retained audio, no data retention policy to read. The only network request is the model download, which is audio-agnostic.
Frequently asked questions
What audio and video formats are supported?
Audio: MP3, WAV, M4A, OGG, FLAC. Video: MP4, WebM, MOV (the audio track is extracted automatically — you do not need to convert the file first). If your file is in a different format, convert it to MP3 first using any free converter.
How accurate is browser-based transcription?
The Whisper model achieves word error rates competitive with human transcription on clean, clearly spoken audio. On recordings with strong accents, background noise, overlapping speech, or technical jargon, accuracy drops noticeably. Accuracy is also sensitive to audio quality — a 128 kbps MP3 of a podcast will transcribe far better than a muffled phone recording. For best results: use a recording with minimal background noise, a single speaker, and clear enunciation.
What languages does it support?
OpenAI Whisper was trained on 99+ languages. The tool includes automatic language detection — it identifies the spoken language and applies the correct model without you selecting it. You can override this manually if needed. English accuracy is highest; other major languages (Spanish, French, German, Japanese, Chinese, etc.) are close behind. Rare languages may have noticeably lower accuracy.
Can I transcribe video files directly?
Yes. Drop an MP4, WebM, or MOV file and the tool extracts the audio track in the browser before passing it to the Whisper model. You do not need to strip the audio separately. The video is never uploaded — extraction happens locally via the Web Audio API.
What is the maximum file length?
Approximately 150 minutes per file. This is a browser RAM constraint, not a server-side limit. Files are processed in 30-second chunks with 5-second overlap, so very long files build up memory over time. If you need to transcribe something longer, split the file first using any audio editor or the Trim Audio tool at simpletool.co/trim-media.
What is the difference between the Base and Small models?
Base is ~75 MB and is the default. It transcribes quickly (roughly real-time or faster on modern hardware) and is accurate enough for most recordings. Small is larger and slower but handles difficult audio better — stronger accents, fast speech, or technical vocabulary. If Base produces frequent errors on your recording, switch to Small. Both models are cached after the first download and load instantly on repeat visits.
Does the file get uploaded to a server?
No. Transcription runs entirely inside your browser tab using Transformers.js. The audio never leaves your device. The only network request is the one-time model download from a CDN (Hugging Face), which is cached locally. Every subsequent run is fully offline.
Transcribe your audio for free
No upload, no account, no minute limits. Whisper AI runs in your browser.
Open Audio Transcriber →