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Superwhisper vs Rhino Voice vs Dictāta: Which Offline AI Dictation Tool Is Right for You?

Superwhisper vs Rhino Voice vs Dictāta: Which Offline AI Dictation Tool Is Right for You?

Dictāta TeamBy Dictāta Team

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Superwhisper, Rhino Voice (sometimes called "Rhino" or "Reno" in online discussions) and Dictāta Local can all transcribe speech on your own device. They differ in platforms, speech engines and what they offer around dictation.

This page states what the vendors publish and what we measured for Dictāta Local. We did not benchmark Superwhisper or Rhino Voice, so there are no latency or memory comparisons here. Vendor details change, so check the linked sites.

At a Glance

Dictāta Local Superwhisper Rhino Voice
Platforms Windows, macOS, Android macOS, Windows, iOS, Android macOS 14+ on Apple Silicon (M1 or newer)
Speech engines NVIDIA Nemotron 3.5 Streaming via sherpa-onnx Local Whisper models; Parakeet and Cohere Transcribe local models and cloud models on Pro On-device Whisper and Parakeet models, plus on-device text cleanup
Works without internet Yes, after a one-time model download Yes with local models; cloud models need a connection Yes, after the models are downloaded
Sources dictata.app docs, plans rhinovoice.app, changelog

Platforms

  • Dictāta Local runs on Windows 10/11 (64-bit, x64 or ARM), macOS and Android. One streaming model is used on all three platforms.
  • Superwhisper documents apps for macOS, Windows, iOS and Android. Its homepage notes that offline models run well only on Apple Silicon Macs.
  • Rhino Voice requires macOS 14 or later on an Apple Silicon Mac (M1 or newer); Intel Macs are not supported.

Speech Recognition: Streaming Model in Dictāta Local

Dictāta Local uses NVIDIA Nemotron 3.5 ASR Streaming 0.6B (560 ms, INT8), run by sherpa-onnx. The model receives audio in 100 ms chunks while you speak, so recognition is largely done when you stop. This is a property of streaming models in general, and it is why the stop-to-text delay stays short regardless of dictation length.

What we measured for Dictāta Local:

Metric Value Conditions
Stop-to-final text ~120–200 ms Windows 11, Ryzen 7 5700U, 4 CPU threads; 33–59 s recordings replayed at real-time speed (122 and 126 ms). Model only, without pasting into the target app. Similar speed seen on a Mac with an M1 chip (macOS 26) and a Google Pixel 9a.
Model memory ~0.8 GB Process working set, flat regardless of dictation length
Real-time factor ~0.27 Built-in speed check after download

The figures come from a replayed recording, not a live microphone. Older or heavily loaded computers will be slower.

Superwhisper and Rhino Voice offer Whisper and Parakeet models, so their speed depends on the model and your hardware. We have not measured either. Rhino's changelog reports internal benchmarks without stating the hardware, so they cannot be compared with ours.

Vocabulary Customization

In Dictāta Local, your Smart Glossary terms (up to 512) are passed to the speech decoder as hotwords with modified beam search, so names and jargon such as Kubernetes or PostgreSQL are favored during recognition. Changed terms apply from the next dictation. Manual text replacements still run afterwards.

Superwhisper lists custom vocabulary and text replacements, and Rhino Voice has a personal dictionary. Their documentation does not say whether the terms influence the recognizer itself or are applied afterwards.

Memory and Disk

For Dictāta Local:

  • The speech model uses about 0.8 GB of memory while active and is unloaded after about 10 minutes without dictation.
  • The one-time download is about 475 MB for the speech model, and about 1.2 GB of free disk space is needed for downloading and unpacking.
  • Minimum 6 GB of RAM, 8 GB recommended. No GPU required.
  • Optional local text models (1.1–3.3 GB each) are needed only for prompts, Casual / Formal styles and text actions.

Current Limits of Dictāta Local

  • Spoken numbers are written as words; digit conversion is not supported yet.
  • Ask Dictāta chat, translation while dictating and Memory need Dictāta Cloud.
  • The product is in preview. Android was tested on a Google Pixel 9a; minimum requirements are still being finalized.

Summary

Choose Dictāta Local if:

  • You use Windows, Mac and Android and want one tool on all of them.
  • You want a streaming model with a short stop-to-text delay and glossary hints in the decoder.
  • You want audio and dictated text to stay on the device while Local mode is on. Besides sign-in, billing, model downloads and the version check, the app blocks other connections.
  • Get started: Dictāta Local

Choose Superwhisper if:

  • You want to choose between several local and cloud models on Mac, Windows, iOS or Android, with custom modes and an enterprise offering. See superwhisper.com for current details.

Choose Rhino Voice if:

  • You work on an Apple Silicon Mac (macOS 14+) and want a small on-device dictation utility with Whisper and Parakeet models. See rhinovoice.app for current details.

Further Reading