Whisper transcription means converting speech to text with OpenAI's Whisper — an open-source AI model you can run in the cloud, on a server, or entirely on your own device. This guide covers how Whisper works, which model size to pick, how accurate it really is, and the fastest way to run it offline on a Mac or iPhone.
What Is Whisper, Exactly?
Whisper is an automatic speech recognition (ASR) model that OpenAI released in September 2022 under the MIT license. It's an encoder-decoder transformer trained on over 680,000 hours of multilingual audio, and it handles transcription in roughly 100 languages plus translation to English.
The part that matters for you: the model weights are open. Unlike Google's or Amazon's speech APIs, Whisper doesn't have to run on someone else's server. An entire ecosystem exists to run it locally — whisper.cpp, faster-whisper, and native apps like Whisper Notes. That's what makes truly offline, private transcription possible.
Whisper Model Sizes: Which One to Use
Whisper comes in six main sizes. Bigger means more accurate and slower:
| Model | Parameters | Speed | Best for |
|---|---|---|---|
| tiny | 39M | Fastest | Quick drafts, weak hardware |
| base | 74M | Very fast | Simple, clean audio |
| small | 244M | Fast | Good speed/accuracy balance on mobile |
| medium | 769M | Moderate | Rarely the right pick today |
| large-v3 | 1.55B | Slowest | Maximum accuracy, difficult audio |
| large-v3-turbo | 809M | ~5x faster than large-v3 | The default choice in 2026 |
For almost everyone, large-v3-turbo is the answer: it keeps large-v3's encoder but cuts decoder layers from 32 to 4, delivering near-identical accuracy at a fraction of the compute. We benchmarked it in detail in Whisper Large V3 Turbo vs V3.
How Accurate Is Whisper Transcription?
On clean English audio, the large models reach a word error rate (WER) of roughly 5-8% — comparable to professional human transcription for most practical purposes. Accuracy drops with background noise, heavy accents, crosstalk, and low-resource languages.
Whisper's one famous failure mode is hallucinations during silence. Its autoregressive decoder sometimes invents repeated phrases or subtitle credits when nobody is speaking. In our specific silence tests, NVIDIA's Parakeet V3 produced no false words; that is a bounded test result, not a claim that any speech model is infallible (full Parakeet V3 vs Whisper benchmark).
For Chinese, Japanese, Korean, and Cantonese, a specialized model beats Whisper on both speed and punctuation: see SenseVoice vs Whisper for CJK languages.
5 Ways to Run Whisper Transcription
| Method | Cost | Privacy | Setup |
|---|---|---|---|
| OpenAI API | Pay per audio minute | Audio uploaded | API key + code |
| openai-whisper (reference Python) | Free | 100% local | Python env, GPU recommended |
| whisper.cpp / faster-whisper | Free | 100% local | Command line |
| Native app (Whisper Notes) | $6.99 once, free trial on Mac | 100% on-device | None |
| Web demo tools | Free tiers | Audio uploaded | None |
The rule of thumb: if you live in a terminal, faster-whisper is excellent. If you're building a product, the API makes sense. If you just want your recordings transcribed privately without touching Python, use a native app — that's the entire reason Whisper Mac apps exist.
Weighing offline tools more broadly — including Windows and Android options? See our complete offline speech-to-text guide.
Whisper vs Newer Local Models (2026)
Whisper started the local transcription era, but it's no longer alone. Speeds below measured on an M4 Pro Mac:
| Model | Languages | Speed | Standout |
|---|---|---|---|
| Whisper Large V3 Turbo | 100+ | ~12x realtime | Widest language coverage |
| Parakeet V3 | 25 (European) | ~100x realtime | 6.32% WER, no silence hallucinations |
| SenseVoice Small | zh, ja, ko, yue, en | ~52x realtime | Best for Chinese, Japanese, Korean |
All three run locally in Whisper Notes, and you can switch per recording. Side-by-side benchmarks live on our Whisper models comparison page.
How to Run Whisper Transcription Offline on Mac & iPhone
No command line required, no Python, no cloud:
- Download Whisper Notes for Mac (free trial) or for iPhone ($6.99 once).
- Pick a model: Whisper Large V3 Turbo for broad language coverage, Parakeet V3 for English speed, SenseVoice for CJK. It downloads once and then works forever offline.
- Record directly, dictate system-wide by holding Fn, or drop in audio and video files (MP3, WAV, M4A, MP4).
- Text streams in as it processes. Export as TXT or SRT.
Skeptical about "offline"? Turn on airplane mode first. Transcription runs at full speed — nothing is uploaded, ever.
Prefer the terminal? The Mac app also ships a whispernotes CLI and a built-in MCP server, so you can transcribe files from a script, search your whole history, or let Claude and other AI assistants read your transcripts — all over a local socket, still fully offline.
Frequently Asked Questions
Is Whisper transcription free?
The model itself is free and open source (MIT license). Running it via command-line tools like whisper.cpp costs nothing but requires setup. OpenAI's API charges per audio minute. Native apps package the models for a small fee — Whisper Notes is $6.99 once, with a free trial on Mac.
Can Whisper transcription run offline?
Yes — that's the point of open weights. Once the model file is on your device, no internet is needed. Whisper Notes runs Whisper Large V3 Turbo on Apple Silicon via CoreML/Metal, fully offline. You can verify with airplane mode.
Which Whisper model is the most accurate?
large-v3 has the best raw accuracy. large-v3-turbo matches it within a fraction of a percent WER while running about 5x faster, which is why it's the default in most tools today.
Does Whisper support my language?
Whisper covers roughly 100 languages, strongest in high-resource ones (English, Spanish, German, French, etc.). For Chinese, Japanese, Korean, and Cantonese, SenseVoice delivers better punctuation and much higher speed on Apple Silicon.
Is there a Whisper transcription app for iPhone?
Yes. Whisper Notes runs Whisper models optimized for the iPhone's Neural Engine (iPhone 12 and newer) — record, import from Voice Memos or Files, and transcribe entirely on-device for $6.99, no subscription.
Download for iOS