Superwhisper transcribes your speech into text using a local Whisper AI model on your Mac. Charm corrects typed text in real-time as you write. They are not competing products - they handle different inputs. Superwhisper converts voice to text; Charm fixes errors in that text when you press Option-Command-V. Together they form the fastest, most private writing stack available on Mac in 2026.
What does Superwhisper do - and what doesn't it do?
Superwhisper is a local voice transcription tool that runs OpenAI's Whisper AI model directly on Apple Silicon hardware. Unlike cloud-based transcription tools, Superwhisper processes your audio on-device using the Mac's Neural Engine - no audio is ever sent to external servers.
You activate Superwhisper with a configurable hotkey, speak your text, and release the key to trigger transcription. Within a second or two, the transcribed text appears in whatever app is currently focused: Slack, Mail, VS Code, a browser tab, a notes app - anywhere. Superwhisper places text via the system accessibility layer, meaning it works in essentially every Mac app.
Superwhisper achieves approximately 97% transcription accuracy on Apple Silicon hardware for clear English speech. The OpenAI Whisper model has a documented word error rate of approximately 4.2% for English - meaning even this state-of-the-art on-device model produces errors in roughly 1 in 24 words. At 150 words per minute of speech, that is around 6 errors per minute of dictation that reach the text field uncorrected.
Superwhisper does not include autocorrect. It transcribes speech and stops there. The errors in the transcription - homophone substitutions, proper noun misrecognitions, grammar distortions from mishearing - are not fixed by Superwhisper. They land in the text field and remain until you correct them manually.
Where Charm fits alongside Superwhisper
Charm operates at the OS kernel level via the Accessibility API and CGEventTap. It corrects what you type as you type it. When Superwhisper pastes a transcription into a field, select it (or select nothing, to fix the whole field) and press Option-Command-V, and Charm fixes the transcription in one go.
The specific types of errors Charm fixes in Superwhisper output, when you press Option-Command-V, include: words misheard as phonetically similar but differently spelled alternatives, grammar errors from mishearing verb endings or articles, punctuation errors from run-on transcription, and occasional word boundary errors where Whisper runs two words together.
Charm's Spells feature fixes spelling, and Polish fixes grammar - the type of error that standard spell checking misses because the wrong word is still a real word. The combined result: Superwhisper transcribes, you press Option-Command-V, and Charm fixes the transcription in one go.
Privacy comparison: both tools are on-device
One of the most compelling things about the Superwhisper + Charm combination is that both tools process data entirely on-device. No audio, keystrokes, or text content leaves your Mac at any point in the workflow.
This stands in sharp contrast to the most commonly compared alternatives:
- Wispr Flow sends audio to cloud transcription servers
- Grammarly sends all typed text to Grammarly's servers
- Fixkey sends selected text to OpenAI's servers
- Apple Dictation (standard mode) sends audio to Apple's servers
For users in legal, healthcare, finance, journalism, or any context where confidentiality matters, the Superwhisper + Charm stack offers a level of privacy that no cloud-dependent combination can match. You get voice-speed input and a one-keystroke correction with zero data transmission.
Superwhisper requires Apple Silicon (M1 or later) for on-device Whisper processing. Charm also needs Apple Silicon, on macOS 14 Sonoma or later. On an Intel Mac, Apple Dictation (Enhanced mode, on-device) is the private voice option, and neither Superwhisper nor Charm will run.
The combined workflow: voice in, corrected text out
The workflow requires no ongoing thought once both tools are set up.
You press Superwhisper's hotkey and speak naturally. Superwhisper processes the audio on-device via Whisper and pastes the transcribed text into the active app within one to two seconds. Pasted text arrives without keystrokes, so Charm does not fix it on its own. Select it (or select nothing, to fix the whole field) and press Option-Command-V, and Charm runs its Spells and Polish passes over the transcription, leaving your intended message accurately spelled and grammatically correct.
The total cost for this stack: Superwhisper at $249 (lifetime) plus Charm at $19.99 (one-time) equals $268.99 with no subscriptions and no future costs. Compare this to two years of Grammarly Premium ($288) which covers only browser-based writing, has no voice input component, and sends all text to cloud servers.
For developers writing comments and commit messages in VS Code, the Superwhisper + Charm combination is particularly powerful: dictate comments at 150 words per minute, then press Option-Command-V to have Charm clean up the transcribed prose. Charm runs in Manual mode in VS Code and other code editors, so your source is never rewritten while you type; elsewhere it corrects automatically as you type. Charm distinguishes prose from code identifiers and only corrects the natural language content.
Frequently asked questions
Does Superwhisper have autocorrect?
No. Superwhisper transcribes speech to text using the Whisper AI model running on-device. It does not apply a correction pass to the transcribed output. Whisper is accurate, but transcription errors still reach the text field. Charm fixes them when you select the text, or nothing, and press Option-Command-V.
Can Charm fix Superwhisper transcription errors?
Yes, with one shortcut. Superwhisper pastes its transcription all at once rather than as keystrokes, so Charm does not fix it automatically. Select it (or select nothing, to fix the whole field) and press Option-Command-V, and Charm fixes the spelling and grammar in it.
Is Superwhisper private?
Yes. Superwhisper runs the OpenAI Whisper model on-device using Apple Silicon's Neural Engine. Your audio is processed entirely on your Mac - no audio or text leaves your device during transcription. Combined with Charm (also fully on-device), the complete voice-to-corrected-text workflow is private end to end.
Which is better for writing - Superwhisper or Wispr Flow?
Superwhisper offers stronger privacy (fully on-device), a one-time lifetime price, and no ongoing cost. Wispr Flow offers cloud-based accuracy that adapts to your vocabulary over time. Both work equally well alongside Charm. Choose based on privacy preference and hardware - Superwhisper requires Apple Silicon (M1 or later).
What is the total cost of Superwhisper plus Charm?
Superwhisper costs $249 as a lifetime purchase. Charm costs $19.99 as a one-time purchase. The combined total is $268.99 with no subscriptions or renewals. This is less than two years of Grammarly Premium ($288), which has no voice component and sends your text to cloud servers.