Claude Sonnet 4.6 vs Gemini 3.1 Pro Preview
Claude Sonnet 4.6 (2026) and Gemini 3.1 Pro Preview (2026) are frontier reasoning models from Anthropic and Google DeepMind. Both ship a 1m-token context window. On MMLU PRO, Gemini 3.1 Pro Preview leads by 3.7 pts. On pricing, Claude Sonnet 4.6 costs $3/1M input tokens; Gemini 3.1 Pro Preview ranges from $2 to $4/1M input tokens by tier. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Gemini 3.1 Pro Preview is safer overall; choose Claude Sonnet 4.6 when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | Claude Sonnet 4.6 | Gemini 3.1 Pro Preview |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | multimodal apps, tool-calling agents, and long-context analysis |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1m | 1m |
| Cheapest output | $15/1M tokens | $12/1M tokens |
| Provider routes | 6 tracked | 5 tracked |
| Shared benchmarks | 14 shared | MMLU PRO leader |
Decision tradeoffs
- Claude Sonnet 4.6 holds a shared-benchmark lead on HumanEval, ahead by 4 points.
- Claude Sonnet 4.6 has broader tracked provider coverage for fallback and route flexibility.
- Claude Sonnet 4.6 uniquely exposes Reasoning, Computer use, and Parallel agents in local model data.
- Local decision data tags Claude Sonnet 4.6 for Coding, RAG, and Agents.
- Gemini 3.1 Pro Preview holds a shared-benchmark lead on MMLU PRO, ahead by 3.7 points.
- Gemini 3.1 Pro Preview has the lower cheapest tracked output price at $12/1M tokens.
- Local decision data tags Gemini 3.1 Pro Preview for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Sonnet 4.6
$6,150
Cheapest tracked route/tier: OpenRouter
Gemini 3.1 Pro Preview
$4,600
Cheapest tracked route/tier: Google AI Studio
Estimated monthly gap: $1,550. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on GCP Vertex AI, OpenRouter, and Vercel AI Gateway; start route-level A/B tests there.
- Gemini 3.1 Pro Preview is $3/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning, Computer use, and Parallel agents before moving production traffic.
- Provider overlap exists on OpenRouter, GCP Vertex AI, and Vercel AI Gateway; start route-level A/B tests there.
- Claude Sonnet 4.6 is $3/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Sonnet 4.6 adds Reasoning, Computer use, and Parallel agents in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-17 | 2026-02-19 |
| Context window | 1m | 1m |
| Parameters | — | — |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-08 | 2025-01 |
Pricing and availability
| Pricing attribute | Claude Sonnet 4.6 | Gemini 3.1 Pro Preview |
|---|---|---|
| Input price | $3/1M tokens |
|
| Output price | $15/1M tokens |
|
| Providers |
Capabilities
| Capability | Claude Sonnet 4.6 | Gemini 3.1 Pro Preview |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | Yes | No |
| Parallel agents | Yes | No |
Benchmarks
| Benchmark | Claude Sonnet 4.6 | Gemini 3.1 Pro Preview |
|---|---|---|
| MMLU PRO | 87.3 | 91.0 |
| SWE-bench Verified | 79.6 | 80.6 |
| Google-Proof Q&A | 89.9 | 94.3 |
| AIME 2025 | 94.0 | 95.0 |
| LiveCodeBench | 80.0 | 91.7 |
| Humanity's Last Exam | 33.2 | 51.4 |
| HumanEval | 98.0 | 94.0 |
| Chatbot Arena | 1459.0 | 1493.0 |
| ARC-AGI-2 | 58.3 | 77.1 |
| MultiChallenge | 57.1 | 71.4 |
| MMMU Pro | 75.6 | 88.2 |
| τ-bench | 87.5 | 76.5 |
| Massive Multitask Language Understanding | 89.3 | 98.0 |
| MCP-Atlas | 61.3 | 69.2 |
Continue comparing
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- Claude Sonnet 4.6 vs Kimi K2.6
- Claude Sonnet 4.6 vs Composer 2.5
- Claude Sonnet 4.6 vs GPT-5.5 Pro
- Claude Sonnet 4.6 vs Gemini 3.5 Flash
- Claude Sonnet 4.6 vs GLM-5.1
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.