Overview
This is not a like-for-like comparison. Gemini 4 Argon is a released Google model with official documentation. Gemini Carbon is an unreleased internal codename, and everything known about it comes from press reporting, not from Google.
Gemini 4 Argon (released)
Generally available since October 13, 2026 through the Gemini API, AI Studio and the Gemini app. Model ID gemini-4-argon.Text, image, video, audio and PDF input; a 1,048,576-token unified context window; long decode up to 1,048,576 output tokens; thinking levels low, medium and high.$2 per 1M input tokens and $10 per 1M output tokens until November 30, 2026, then $4 and $20.Gemini Carbon (reported, unreleased)
On October 9, 2026 Business Insider reported that Google employees were testing a Gemini 4 version codenamed Carbon on Jetski, Google's internal coding platform. The report was based on documents and screenshots.One employee said Carbon "feels like Opus 5.5" for coding, with the caveat that it needed more testing.The report says Google has tested Gemini 4 models codenamed Argon, Barium and Carbon, and that internal "Barium-B" was chosen to become the public Argon. It could not determine whether Carbon will ship as an Argon update or as a separate model.Google declined to comment, and there is no guarantee it will be released.What this means
There are no official specs, prices, context limits or benchmarks for Carbon, so this page does not invent any. We will update it if Google announces the model.
No hands-on testing was conducted for this comparison. Every figure above comes from the official pages listed under Research sources, as published on or before October 22, 2026. Where a vendor has not published a number, we say so instead of estimating it.