Offline speech to text that runs entirely on your device

VoicePad uses OpenAI Whisper running locally — no cloud processing, no internet connection required after the initial model download. True on-device speech recognition for Windows, macOS, iOS, and Android.

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Whisper AI on-device · No internet after setup · 99 languages · No subscription

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What "offline" actually means for speech to text

Most speech recognition services — Google Speech-to-Text, Amazon Transcribe, Microsoft Azure Speech — require an internet connection. Your voice audio is sent to remote servers, processed there, and results are sent back. This has three problems:

  • Privacy: Your voice data is transmitted to and stored on third-party servers
  • Availability: No internet = no functionality. Airplane, basement, rural area = unusable
  • Cost: Per-minute billing adds up. Heavy users pay hundreds per month

Offline speech to text solves all three. The speech recognition model runs locally on your device. Audio never leaves your hardware. Works without any network connection. One-time cost.

VoicePad implements this using OpenAI's Whisper model — the same engine that powers the best transcription services — packaged to run directly on your Windows PC, Mac, iPhone, or Android phone.

How VoicePad delivers offline speech to text

Running Whisper offline requires more than just the model. VoicePad adds five layers that make it actually usable for real-time dictation:

1. Model optimization — Whisper weights are converted to platform-optimized formats: GGUF for whisper.cpp (Windows/Android) and CoreML for WhisperKit (macOS/iOS). This enables GPU/NPU acceleration without requiring CUDA or manual setup.

2. Voice Activity Detection (VAD) — Silero VAD runs continuously, detecting when you're actually speaking. Whisper only processes audio segments with speech — saving CPU cycles and preventing hallucinations on silence.

3. Hallucination filtering — Whisper has a known issue: it sometimes outputs phantom text on silence ("Thank you", "Subscribe", etc.). VoicePad's filter catches these with a 387-phrase blacklist plus pattern matching.

4. Smart chunking — For real-time feel, audio is processed in segments (1-3 seconds) rather than waiting for complete utterances. This adds engineering complexity but makes the experience feel instant.

5. Text injection — Transcribed text needs to reach your target app (WhatsApp, Word, ChatGPT). VoicePad handles this differently per OS: Win32 SendInput on Windows, Accessibility API on Mac, keyboard extension on iOS, AccessibilityService on Android.

The result: speak, see text appear in any app, no internet involved at any step.

Model sizes and system requirements

Model Download RAM needed Speed Best for
Whisper Tiny ~75 MB ~400 MB Fastest Older phones, low-spec devices
Whisper Small (default) ~480 MB ~1 GB Fast Most users — best accuracy/speed balance
Whisper Medium (Pro) ~1.5 GB ~2.6 GB Moderate Power users, desktop systems
Whisper Large-v3 (planned) ~3 GB ~5.5 GB Slow Workstations, maximum accuracy

Minimum requirements:

  • Windows: Windows 10 or later, 4 GB RAM, any CPU from the last 5 years
  • macOS: macOS 12+, works on Intel and Apple Silicon (M1+ runs ~3x faster)
  • iOS: iPhone 8 or later, iOS 15+
  • Android: Android 8+, 3 GB RAM minimum, 4 GB+ recommended

No dedicated GPU required. Whisper Small runs in real-time on a 5-year-old laptop CPU. On Apple Silicon or with CUDA on Windows, performance is significantly better.

Technical stack per platform

Component Windows macOS iOS Android
Whisper runtime whisper.cpp WhisperKit WhisperKit whisper.cpp (JNI)
Acceleration CPU + optional CUDA Metal + Neural Engine CoreML + Neural Engine CPU (NEON SIMD)
VAD engine Silero (ONNX) Silero (CoreML) Silero (CoreML) Silero (ONNX)
Audio capture WASAPI AVAudioEngine AVAudioEngine AudioRecord
Text injection Win32 SendInput Accessibility API Keyboard extension AccessibilityService
Activation System tray + hotkey Menu bar + hotkey Keyboard button Float Orb overlay

Each platform uses native APIs for best performance. No Electron wrapper, no web views, no cross-platform compromises that sacrifice speed.

Offline speech to text: VoicePad vs alternatives

Solution Truly offline Platforms Live dictation Price
VoicePad AI Yes, 100% Win+Mac+iOS+Android Yes $0-50 one-time
Windows Voice Typing Partial (Enhanced = cloud) Windows only Yes Free
Apple Dictation Partial (Enhanced = cloud) Apple only Yes Free
Google Voice Typing No Android/Gboard Yes Free
Dragon NaturallySpeaking Yes Windows only Yes $500+
Whisper.cpp (CLI) Yes All (technical) No (batch) Free
Otter.ai No Web/Mobile Yes $17/mo

Note: Windows and Apple's "Enhanced" dictation modes send audio to servers. Only their basic modes are truly offline — and those have lower accuracy. VoicePad is always offline with Whisper-level accuracy.

Accuracy comparison: offline vs cloud

Condition VoicePad (Whisper Small) Google Cloud Speech Windows Offline
Clean English 96-98% 97-99% 88-92%
Clean German 94-97% 95-98% 82-88%
Accented English 92-96% 93-97% 80-88%
Background noise 90-95% 92-96% 75-85%
Technical vocabulary 90-95% 88-94% 70-82%

Whisper matches or beats cloud services on most conditions. The gap is small on clean audio. Where cloud wins: very noisy environments and rare languages with limited Whisper training data.

VoicePad's custom dictionary adds another 1-2% by correcting consistent errors (proper nouns, technical terms, brand names).

Frequently asked questions

Does offline speech to text really work without any internet?
Yes, completely. VoicePad downloads the Whisper model once (250 MB for Small, 800 MB for Medium), then runs 100% on your device. No network connection needed ever again. Works in airplane mode, underground, or anywhere without signal.
How accurate is offline speech recognition compared to cloud services?
Whisper achieves 95-98% accuracy on clean English and 94-97% on German — comparable to or better than Google Speech API in most conditions. The gap only appears on very noisy audio or rare languages where cloud services have more training data.
Why would I choose offline speech to text over cloud-based services?
Privacy: your voice never leaves your device. Availability: works without internet. Cost: one-time price vs per-minute billing. Latency: no network roundtrip. Compliance: GDPR/HIPAA friendly since no data leaves your control.
What hardware do I need for offline speech to text?
Whisper Small runs well on any device from the last 5 years: Windows 10+ PC, Mac with Intel or Apple Silicon, iPhone 8+, or mid-range Android phone. No dedicated GPU required. Whisper Medium needs 2.6 GB RAM — better for desktops.
Is there a speed difference between offline and cloud speech recognition?
Depends on your connection. On fiber internet, cloud might be marginally faster. On mobile data, congested WiFi, or any poor connection, offline wins by seconds. On a plane or underground, offline is the only option that works at all.
Can offline speech to text work in multiple languages?
Yes. Whisper supports 99 languages in one model — no language packs to download. English and German have the best accuracy (95%+), followed by French, Spanish, Portuguese, Italian. Lower-resource languages have higher error rates.
What happens to my transcriptions — are they stored anywhere?
Stored locally on your device only. VoicePad keeps a searchable history of your transcriptions in local storage. Nothing is ever uploaded to any server. You can export or delete your history at any time.

Try offline speech to text

Free standard tier on all platforms. Founding members get lifetime Pro access (Whisper Medium + WiFi Sync) — — spots remaining.

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