Whisper AI Transcription Online
Run OpenAI Whisper directly in your browser — no server uploads, no API keys, no subscription. Transcribe any audio or video file with state-of-the-art accuracy. Export as SRT, VTT, or plain text.
Upload a file · Boost, EQ, export · 100% in your browser
OpenAI's Whisper is the most accurate speech-to-text model publicly available, trained on 680,000 hours of multilingual audio data. It handles accents, background noise, technical jargon, and code-switching between languages with remarkable precision. But using Whisper has traditionally required either Python programming knowledge (to run the model locally), or sending your audio to a cloud API — which means uploading potentially sensitive recordings to third-party servers, paying per minute of audio, and trusting that your files are handled responsibly.
Hearably Studio eliminates every one of these barriers. It runs Whisper AI transcription online directly in your browser using WebAssembly and WebGPU acceleration. When you drop an audio or video file onto the studio, the Whisper model loads into your browser's memory and processes the audio entirely on your device. No bytes leave your machine. No API key required. No per-minute charges. No account creation. The transcription is yours — private, instant, and free.
This matters enormously for anyone working with sensitive content. Journalists transcribing confidential interviews. Lawyers processing depositions. Medical professionals handling patient recordings. HR teams reviewing employee conversations. Researchers working with IRB-protected data. In all these cases, uploading audio to a cloud transcription service creates compliance risks — GDPR, HIPAA, attorney-client privilege, IRB protocols. Whisper AI transcription online in Hearably Studio removes this risk entirely because the audio never leaves the device. There is no server to breach, no data to subpoena, no third-party processor to audit.
The accuracy is exceptional. Whisper's architecture — a Transformer encoder-decoder trained with weak supervision on massive multilingual data — achieves word error rates (WER) competitive with commercial services like Rev, Otter.ai, and Google Speech-to-Text. For English content, Hearably's Whisper implementation typically achieves 5-8% WER on clean speech and 12-18% WER on noisy recordings. It supports over 90 languages with automatic language detection, meaning you don't need to specify the source language — Whisper identifies it from the first 30 seconds of audio.
Beyond raw transcription, Hearably Studio pairs Whisper with a complete audio enhancement pipeline. If your recording is noisy, quiet, or poorly mixed, you can boost volume, apply EQ, and compress dynamics before transcribing — which directly improves transcription accuracy by giving Whisper a cleaner input signal. You can also use Magic Cut to automatically remove filler words ("um," "uh," "like," "you know") from the transcript, and export the result as SRT subtitles, VTT captions, or plain text. The entire workflow — enhance, transcribe, clean, export — runs in a single browser tab with zero external dependencies.
How Whisper AI Runs in Your Browser — WebAssembly + WebGPU
Running a large neural network like Whisper inside a browser tab sounds improbable, but modern web APIs make it practical. Hearably Studio uses a WebAssembly (WASM) compiled version of Whisper — specifically, the whisper.cpp implementation by Georgi Gerganov, compiled to WASM with SIMD (Single Instruction, Multiple Data) extensions enabled. This gives the model near-native execution speed on any modern browser without requiring Python, CUDA, or any local installation.
On devices with compatible GPUs, the studio leverages WebGPU for matrix multiplication and attention computation — the two most compute-intensive operations in the Transformer architecture. WebGPU provides direct access to the GPU's shader cores, delivering 3-5x speedup over CPU-only WASM inference. On a modern laptop with integrated graphics, a 5-minute audio file typically transcribes in 15-30 seconds. On devices with dedicated GPUs (NVIDIA, AMD, Apple Silicon), processing is even faster — often faster than real-time.
The model weights are cached in the browser's Cache Storage API after the first download, so subsequent uses load instantly without re-downloading the ~75MB model file. Hearably uses the Whisper "small" model by default, which balances accuracy and speed. The audio preprocessing pipeline converts any input format to 16kHz mono PCM (Whisper's expected input format) using the Web Audio API's OfflineAudioContext with automatic resampling. This means you can feed Whisper AI transcription online any format your browser can decode — MP3, WAV, FLAC, OGG, AAC, M4A, MP4, WebM — without manual conversion.
The decoder runs with beam search (beam width 5) and temperature fallback — if the initial decoding pass produces high-entropy tokens (indicating uncertainty), the model automatically re-runs with increased temperature for better exploration of the probability space. Timestamp tokens are extracted at the segment level, enabling SRT and VTT export with accurate timing. The entire inference pipeline is single-threaded on the main WASM thread but offloads matrix operations to WebGPU when available, keeping the browser UI responsive during processing.
How to get the best audio on Whisper AI Transcription Online
Enhance audio before transcribing for better accuracy
Whisper performs best on clean, loud speech. If your recording is quiet or noisy, use Hearably Studio's volume boost and EQ before running transcription. Boosting to 200-300% and applying Voice Boost (1-4 kHz emphasis) can reduce word error rate by 20-40% on poor-quality recordings. The look-ahead limiter prevents any clipping during boost.
Use Magic Cut to clean up the transcript
After Whisper generates the raw transcription, enable Magic Cut to automatically identify and remove filler words — "um," "uh," "like," "you know," "basically," "sort of." This produces a cleaner, more professional transcript suitable for publication, subtitles, or meeting notes without manual editing.
Export as SRT for video subtitles
Whisper generates segment-level timestamps that map directly to SRT subtitle format. After transcription, click Export SRT to get a ready-to-use subtitle file. Import it into any video editor (Premiere, DaVinci, CapCut), upload to YouTube as captions, or use with media players like VLC for instant playback subtitles.
Process long recordings in segments
For recordings longer than 30 minutes, Whisper automatically splits audio into 30-second segments for processing. This happens transparently — you see a progress bar, and the final transcript is a single continuous document. On older hardware, very long files (2+ hours) may benefit from splitting into shorter clips for faster processing.
Leverage automatic language detection
Whisper identifies the spoken language from the first 30 seconds of audio. You don't need to specify whether the recording is in English, Spanish, Japanese, or any of 90+ supported languages. For multilingual content that switches between languages mid-sentence, Whisper handles code-switching natively.
Use the VTT format for web video players
If you're adding captions to a web video (HTML5 video element, custom player), export as WebVTT (.vtt) instead of SRT. VTT is the native caption format for web browsers and supports styling metadata. Both formats contain identical text and timing data — the difference is syntax compatibility with your target platform.
Cache the model for instant future use
The Whisper model file (~75 MB) downloads once and is cached in your browser's storage. Subsequent transcription sessions load the model from cache in under 2 seconds. If you clear browser data, the model will re-download on next use. Keeping the cache saves significant time for frequent transcription workflows.
Verify accuracy on critical content
Whisper achieves 5-8% WER on clean English speech, meaning roughly 1 in 15 words may need correction. For legal, medical, or published content, always review the transcript manually. Proper nouns, brand names, and domain-specific jargon are the most common error categories — a quick search-and-replace pass handles most corrections.
Built for this exact use case
100% Private — Zero Server Uploads
Whisper runs entirely in your browser via WebAssembly and WebGPU. Your audio files never leave your device. No API keys, no cloud processing, no third-party data exposure. Safe for GDPR, HIPAA, and confidential content.
90+ Languages with Auto-Detection
Whisper identifies the spoken language automatically and transcribes with state-of-the-art accuracy across 90+ languages. Handles accents, code-switching, and technical terminology without manual configuration.
SRT, VTT & Plain Text Export
Export your transcription as SRT subtitles (for video editors), WebVTT captions (for web players), or plain text (for documents). Timestamps are automatically extracted at the segment level with accurate synchronization.
Enhance + Transcribe in One Workflow
Boost volume, apply EQ, and compress dynamics before transcribing — all in the same tool. Cleaner audio input means better Whisper accuracy. Then use Magic Cut to remove filler words from the transcript automatically.
Choose your method
Different situations call for different tools. Hearably gives you both.
Chrome Extension
Enhance audio live while you stream. The extension intercepts your tab's audio and processes it in real-time — volume boost, EQ, presets — without downloading anything.
- Streaming on Whisper AI Transcription Online, Netflix, Spotify
- Video calls on Zoom, Meet, Teams
- Any website with audio
- When you want instant, always-on enhancement
Free Online Studio
Upload an audio or video file, apply volume boost + 10-band EQ, preview in real-time, then download the enhanced WAV. Your file never leaves your browser.
- Downloaded videos or music files
- Podcast episodes you want to boost before sharing
- Voice recordings, lectures, interviews
- When you need a permanently enhanced file
Pro tip: Use a YouTube-to-MP3 tool to download the audio, then enhance it in Hearably Studio with EQ + volume boost. Perfect for offline listening, DJ sets, or sharing on social media.
Three clicks to better audio
Install
Add Hearably from the Chrome Web Store. Under 300KB, installs in seconds.
Enhance
Click the Hearably icon and tap "Enhance." Boost kicks in instantly.
Enjoy
Adjust volume, EQ, and presets. Works on any website with audio.
Frequently asked questions
Is this really free Whisper AI transcription online?
Yes. Hearably Studio runs OpenAI's Whisper model directly in your browser at zero cost. There are no per-minute charges, no API keys, no account required, and no usage limits. The model runs on your device's CPU and GPU — no server infrastructure costs mean no reason to charge.
How accurate is browser-based Whisper compared to the cloud API?
Hearably Studio uses the Whisper "small" model, which achieves 5-8% word error rate on clean English speech — within 1-2 percentage points of the cloud API's "small" endpoint. For most practical purposes, accuracy is indistinguishable. The cloud API offers the larger "large-v3" model which is marginally more accurate on difficult content.
Do my audio files get uploaded to any server?
No. All processing — audio decoding, Whisper inference, and export encoding — runs entirely in your browser. You can verify this by disconnecting from the internet after the page loads (and after the model is cached). Transcription works fully offline. No data is transmitted anywhere.
What audio and video formats are supported?
Any format your browser can decode: MP3, WAV, FLAC, OGG, AAC, M4A, MP4, WebM, and MOV. For video files, the audio track is extracted automatically. The studio converts all input to 16kHz mono PCM — Whisper's expected format — using the Web Audio API.
How long does transcription take?
On modern hardware (2020+ laptop or desktop), roughly 15-30 seconds per 5 minutes of audio. Devices with WebGPU support (dedicated or integrated GPU) are 3-5x faster. The Whisper model caches after first download, so subsequent sessions start instantly. A 1-hour recording typically processes in 3-6 minutes.
Can Whisper handle multiple languages in one recording?
Yes. Whisper handles code-switching natively — if speakers switch between languages mid-sentence, the model transcribes each segment in the correct language. It also auto-detects the primary language from the first 30 seconds, so you never need to specify the language manually.
What is the maximum file size or duration?
There is no hard limit — processing runs locally so there are no server-imposed restrictions. Practical limits depend on your device's memory. Most modern devices comfortably handle files up to 2-3 hours. For very long recordings (4+ hours), splitting into smaller segments may improve stability.
How does enhancing audio before transcription improve accuracy?
Whisper was trained primarily on clean, well-recorded speech. Quiet recordings, background noise, and poor microphone quality all increase word error rate. Boosting volume to a comfortable level, applying Voice Boost EQ (1-4 kHz), and using the compressor to even out speaker levels gives Whisper a signal closer to its training data — measurably improving accuracy by 20-40% on poor recordings.
Can I use the transcription output as YouTube captions?
Yes. Export as SRT and upload directly to YouTube Studio as a subtitle file. YouTube accepts SRT format natively and will use your timestamps for caption synchronization. This is significantly more accurate than YouTube's built-in auto-captions, especially for accented speech, technical content, and non-English languages.
Is this the same Whisper model that OpenAI uses?
Yes. Hearably Studio runs an authentic Whisper model (the "small" variant with 244M parameters) compiled to WebAssembly from the official architecture. The weights, tokenizer, and decoder logic are identical to what the OpenAI API serves. The only difference is execution environment — your browser instead of OpenAI's servers.