tertiusChoose Tertius when the input itself is spoken or recorded and you want to select what the result should become. Keep Grammarly in consideration when your larger need is grammar, spelling, clarity, style, and tone suggestions across text you type.
| Need | Tertius private beta | Grammarly, per official material |
|---|---|---|
| Core purpose | Transcribe voice or imported media, then apply a selected outcome. | Review and improve writing with grammar, spelling, clarity, style, punctuation, and tone suggestions. |
| Speech-to-text on Windows | Windows shortcut capture with optional copy and auto-paste. | Grammarly’s official speech-to-text documentation currently describes the Grammarly Keyboard for iOS. Its Windows app provides writing assistance. |
| Recorded media | Imports common audio and video files up to three hours. | No comparable long-media transcription workflow is described in the official speech-to-text page reviewed for this comparison. |
| After transcription | Choose clean text, notes, summary, email, actions, or another playbook-driven format. | Official iOS material describes light cleanup during dictation and separate generative AI options for shortening, tone, or restructuring. |
| History | Optional local Trail history for transcript, outcome, and metadata; no source media. | Official iOS speech-to-text support says past dictations cannot be recovered and voice recordings are not stored. |
| Commercial status | Controlled Windows beta with a managed tester account. The current free allowance includes 120 transcription minutes per month plus outcome processing, subject to beta limits. | Free and subscription plans are documented; check current official plans. |
Where Tertius can replace voice typing
Tertius can cover a direct voice-to-field workflow on Windows: place the cursor, trigger capture, speak, and let the finished result return through copy or paste. It adds an explicit outcome before capture, which matters when one recording should become meeting notes and another should become a client email.
It can also start from an existing file. That makes it relevant to recorded calls, interviews, lectures, webinars, field notes, and voice memos—not only words spoken into a live text field.
Where it does not replace Grammarly
Tertius is not a continuous grammar checker, browser writing overlay, plagiarism checker, or general editor for everything you type. It does not underline writing issues across applications. Some people may use both products: Tertius to create a usable first draft from speech, then a writing assistant or human edit for the final review.
Questions to test before switching
- Do you need Windows speech capture today, or mobile iOS dictation?
- Does your work begin as live speech, a saved recording, or existing typed text?
- Do you want automatic cleanup only, or a repeatable structure such as decisions, actions, and open questions?
- Do you need recoverable local text history?
- Does the current free tester allowance fit your expected recording volume, and are you comfortable with limits changing during beta?
First-party references: Grammarly’s speech-to-text documentation and product overview. Competitor features can change; this page was reviewed on 27 July 2026.