Claude Sonnet 4.5 vs Gemini 4 Carbon
Anthropic · US | Google · US · Updated June 2026
Quick verdict
Pick Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch or computer use and gui automation (61.4% osworld at launch). Pick Gemini 4 Carbon for ranked first on the artificial analysis intelligence index v5.0 with 59 at launch (artificial analysis now shows 60) or google-reported 88.2% on sec-bench pro and 54.8% on exploitgym for vulnerability discovery and exploit validation. On a tight budget at scale, Gemini 4 Carbon is the value pick.
Claude Sonnet 4.5 (Anthropic) and Gemini 4 Carbon (Google) are two of the models people most often weigh against each other in 2026. Claude Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. 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. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: Gemini 4 Carbon is about 1.5× cheaper on input ($2/$10 per 1M tokens vs $3/$15 per 1M tokens) — modest, but it adds up at steady volume.
- ▸Context window: Gemini 4 Carbon holds 5× more — 1M tokens (~1,500 pages) vs 200K (~300 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
- ▸Recency: Gemini 4 Carbon is the newer model by about 13 months (released October 28, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Claude Sonnet 4.5 | Gemini 4 Carbon |
|---|---|---|
| Provider | Anthropic (US) | Google (US) |
| Released | September 29, 2025 | October 28, 2026 |
| Context window | 200K (~300 pages) | 1M tokens (~1,500 pages) |
| Price (in/out) | $3/$15 per 1M tokens | $2/$10 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, code | text, image, audio, video, code |
| SWE-Bench Verified | 77.2% | Not published |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch
Claude Sonnet 4.5
Gemini 4 Carbon is comparatively weak here — no public API model listing yet, so most users cannot call it today
Computer use and GUI automation (61.4% OSWorld at launch)
Claude Sonnet 4.5
Claude Sonnet 4.5 lists computer use and GUI automation (61.4% OSWorld at launch) among its strengths; Gemini 4 Carbon does not.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks
Claude Sonnet 4.5
Claude Sonnet 4.5 lists long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks 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 runs cheaper at $2/$10 per 1M tokens.
Google-reported 88.2% on SEC-bench Pro and 54.8% on ExploitGym for vulnerability discovery and exploit validation
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 carries the larger 1M tokens context.
Google-reported 71.0% on CWE-bench for patching
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.
Lowest cost at scale
Gemini 4 Carbon
At $2/$10 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Gemini 4 Carbon
Its 1M tokens window is about 5× larger than Claude Sonnet 4.5's 200K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Gemini 4 Carbon
At $2/$10 per 1M tokens it undercuts Claude Sonnet 4.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Gemini 4 Carbon
Larger 1M tokens window fits more in one prompt.
Anyone whose priority is agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch
→ Claude Sonnet 4.5
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.
Claude Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs are real: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 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
Claude Sonnet 4.5 and Gemini 4 Carbon overlap enough that the right pick depends on your specific job. Gemini 4 Carbon costs less per token; Gemini 4 Carbon holds the larger context; and each leads in its own area — Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch, Gemini 4 Carbon for ranked first on the artificial analysis intelligence index v5.0 with 59 at launch (artificial analysis now shows 60). Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Sonnet 4.5 and Gemini 4 Carbon without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
See pricingFrequently asked questions
Is Claude Sonnet 4.5 or Gemini 4 Carbon better for coding?
Public SWE-Bench figures are not available for Gemini 4 Carbon, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch 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, Claude Sonnet 4.5 or Gemini 4 Carbon?
Gemini 4 Carbon is cheaper — $3/$15 per 1M tokens vs $2/$10 per 1M tokens, roughly 1.5× apart on input.
Which has the bigger context window?
Gemini 4 Carbon — 1M tokens vs 200K, about 5× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Sonnet 4.5 and Gemini 4 Carbon together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.5, Gemini 4 Carbon and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Sonnet 4.5 or Gemini 4 Carbon?
Gemini 4 Carbon — released October 28, 2026, about 13 months after Claude Sonnet 4.5.
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.