Google Gemini 4 Carbon Guide

Gemini 4 Carbon is the name of an unreleased Google Gemini 4 model. It was first reported in early October 2026 as an internal test build used by Google staff in an internal coding tool called Jetski.

As of October 30, 2026, Google has not officially announced Carbon, its release date, or its pricing.

Treat everything about Carbon as reported, not confirmed, until Google announces it.

Gemini 4 Argon is Google’s public frontier model, announced on September 30, 2026. Carbon is described as the next Gemini 4 checkpoint after Argon. Reports disagree on whether it will ship as a separate model or as an update under the Argon name.

• Reports in early October said Google staff were testing it internally
• Testers reported a Carbon checkpoint on LMArena from around October 20
• Posts on X said early access for partners had started around October 21
• A leaked screenshot reportedly showed a “gemini-4-carbon-preview” model ID

Coding

One Google employee reportedly compared it to Claude Opus 5.5

3D work

Testers say it beats Argon on 3D scenes and voxel builds

Front-end UI

Testers say it is still weak at interface design

Speed

Reported as slower than Argon, but more thorough

These come from hand-picked prompts and individual testers, not benchmarks.

Confirmed

Gemini 4 Argon is public; Google runs an invite-only Gemini API early access program

Not confirmed

Carbon’s release date, price, benchmarks, context window, and final name

• Build a small test set of your real tasks now
• Run it on Argon and your current model to get a baseline
• Include coding, writing, and any 3D or visual tasks you care about
• Note speed and cost, not just quality

• Run the same test set on the same day
• Score blind if you can
• Check results on your work, not viral demos
• Wait for official benchmarks and pricing

• The Google blog and Google DeepMind site
• Gemini API release notes and Google AI Studio
• The Gemini app’s model picker

• Ignore sites selling “Carbon access” before Google releases it
• Do not paste API keys into unofficial tools
• Use only Google AI Studio, the Gemini API, Vertex AI, or the Gemini app