Gemini 3.1 Pro vs Gemini 4 Carbon
Google · US | Google · US · Updated June 2026
Quick verdict
Both are Google models. Gemini 4 Carbon is the newer, generally stronger default; reach for Gemini 3.1 Pro when a specific cost or latency profile matters more than the latest capabilities.
Gemini 3.1 Pro and Gemini 4 Carbon are both Google models, so the real question is not which lab to trust but which tier fits your workload and budget. Gemini 3.1 Pro is a 1M-token multimodal workhorse — huge breadth across text, image, audio and video, but recall fades deep in the window. Gemini 4 Carbon is google's October 28, 2026 limited release for cyber defenders - top of the Artificial Analysis index at launch, priced at $2/$10 introductory, with no public API date yet. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences at a glance
- ▸Context window: 1M vs 1M tokens — within a few percent of each other, so treat this as a tie and test on your own long inputs, since usable recall varies by model.
- ▸Recency: Gemini 4 Carbon is the newer model by about 8 months (released October 28, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Gemini 3.1 Pro | Gemini 4 Carbon |
|---|---|---|
| Provider | Google (US) | Google (US) |
| Released | February 19, 2026 | October 28, 2026 |
| Context window | 1M (~1,573 pages) | 1M tokens (~1,500 pages) |
| Price (in/out) | $2/$12 per 1M tokens | $2/$10 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, audio, video, code | text, image, audio, video, code |
| SWE-Bench Verified | Not published | Not published |
| MRCR v2 @ 1M | 26.3% | Not published |
Who wins what
Full multimodal input — text, image, audio and video in one 1M-token window
Gemini 3.1 Pro
Gemini 4 Carbon is comparatively weak here — google has not published context or modality specs - the 1M window and modalities shown come from Artificial Analysis and Vals
Long video and document analysis
Gemini 3.1 Pro
Gemini 3.1 Pro lists long video and document analysis among its strengths; Gemini 4 Carbon does not.
Agentic reasoning (high ARC-AGI-2)
Gemini 3.1 Pro
Gemini 3.1 Pro lists agentic reasoning (high ARC-AGI-2) among its strengths; Gemini 4 Carbon does not.
Ranked first on the Artificial Analysis Intelligence Index v5.0 with 59 at launch (Artificial Analysis now shows 60)
Gemini 4 Carbon
Google's October 28, 2026 limited release for cyber defenders - top of the Artificial Analysis index at launch, priced at $2/$10 introductory, with no public API date yet — and it is the newer of the two.
Google-reported 88.2% on SEC-bench Pro and 54.8% on ExploitGym for vulnerability discovery and exploit validation
Gemini 4 Carbon
Gemini 3.1 Pro is comparatively weak here — superseded within Google's own line by the newer 3.5/3.6 Flash releases for cost-sensitive work
Google-reported 71.0% on CWE-bench for patching
Gemini 4 Carbon
Gemini 4 Carbon lists google-reported 71.0% on CWE-bench for patching among its strengths; Gemini 3.1 Pro does not.
Which should you pick?
Someone analysing very long documents or codebases
→ Gemini 3.1 Pro
Larger 1M window fits more in one prompt.
Anyone whose priority is full multimodal input — text, image, audio and video in one 1m-token window
→ Gemini 3.1 Pro
It is specifically built for that.
Anyone whose priority is ranked first on the artificial analysis intelligence index v5.0 with 59 at launch (artificial analysis now shows 60)
→ Gemini 4 Carbon
That is its strongest area.
Gemini 3.1 Pro: where it fits
A 1M-token multimodal workhorse — huge breadth across text, image, audio and video, but recall fades deep in the window. Released February 19, 2026 by Google, it is built for full multimodal input — text, image, audio and video in one 1M-token window, long video and document analysis, agentic reasoning (high ARC-AGI-2), and broad multimodal understanding across formats.
Its trade-offs are real: long-context recall drops sharply past 256K (26.3% on MRCR v2 at 1M), premium price per token at $2/$12, and superseded within Google's own line by the newer 3.5/3.6 Flash releases for cost-sensitive work. At $2 in / $12 out per million tokens, it sits in the mid price band.
Gemini 4 Carbon: where it fits
Google's October 28, 2026 limited release for cyber defenders - top of the Artificial Analysis index at launch, priced at $2/$10 introductory, with no public API date yet. Released October 28, 2026 by Google, it is built for ranked first on the Artificial Analysis Intelligence Index v5.0 with 59 at launch (Artificial Analysis now shows 60), google-reported 88.2% on SEC-bench Pro and 54.8% on ExploitGym for vulnerability discovery and exploit validation, google-reported 71.0% on CWE-bench for patching, and introductory $2/$10 per million tokens, matching Gemini 4 Argon, with cached input 95% off.
Its trade-offs: limited release: rolling out to a subset of cyber defenders, then trusted partners via the Fairwind Program, with no date for developers or consumers, no public API model listing yet, so most users cannot call it today, introductory pricing rises to $4/$20 afterward, and Google has not said when that happens, and google has not published context or modality specs - the 1M window and modalities shown come from Artificial Analysis and Vals. At $2 in / $10 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Because Gemini 3.1 Pro and Gemini 4 Carbon come from the same lab (Google), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Gemini 4 Carbon is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to Gemini 4 Carbon and drop down only with a concrete reason.
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See pricingFrequently asked questions
Is Gemini 3.1 Pro or Gemini 4 Carbon better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Gemini 3.1 Pro leans toward full multimodal input — text, image, audio and video in one 1m-token window while Gemini 4 Carbon leans toward ranked first on the artificial analysis intelligence index v5.0 with 59 at launch (artificial analysis now shows 60), and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Gemini 3.1 Pro or Gemini 4 Carbon?
They are priced almost identically, so cost will not decide between them.
Which has the bigger context window?
Effectively neither — 1M vs 1M tokens is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.
Should I upgrade from Gemini 3.1 Pro to Gemini 4 Carbon?
Since both are Google models, the newer one (Gemini 4 Carbon) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, Gemini 3.1 Pro or Gemini 4 Carbon?
Gemini 4 Carbon — released October 28, 2026, about 8 months after Gemini 3.1 Pro.
Related comparisons
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.