Claude Sonnet 4.5 vs Gemma 4 31B IT
Claude Sonnet 4.5 (2025) and Gemma 4 31B IT (2026) are frontier reasoning models from Anthropic and Google DeepMind. Claude Sonnet 4.5 ships a 200k-token context window, while Gemma 4 31B IT ships a 256k-token context window. On MMLU PRO, Claude Sonnet 4.5 leads by 0.8 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Gemma 4 31B IT is safer overall; choose Claude Sonnet 4.5 when reasoning depth matters.
Decision scorecard
Local evidence first| Signal | Claude Sonnet 4.5 | Gemma 4 31B IT |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | multimodal apps, tool-calling agents, and provider-routed production |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 200k | 256k |
| Cheapest output | $15/1M tokens | $0.38/1M tokens |
| Provider routes | 8 tracked | 5 tracked |
| Shared benchmarks | MMLU PRO leader | 2 shared |
Decision tradeoffs
- Claude Sonnet 4.5 holds a shared-benchmark lead on MMLU PRO, ahead by 0.8 points.
- Claude Sonnet 4.5 has broader tracked provider coverage for fallback and procurement flexibility.
- Claude Sonnet 4.5 uniquely exposes Reasoning and Tool use in local model data.
- Local decision data tags Claude Sonnet 4.5 for Coding, RAG, and Agents.
- Gemma 4 31B IT holds a shared-benchmark lead on Google-Proof Q&A, ahead by 0.9 points.
- Gemma 4 31B IT has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Gemma 4 31B IT has the lower cheapest tracked output price at $0.38/1M tokens.
- Local decision data tags Gemma 4 31B IT 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 4.5
$6,150
Cheapest tracked route/tier: Microsoft Foundry
Gemma 4 31B IT
$199
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $5,951. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on GCP Vertex AI and OpenRouter; start route-level A/B tests there.
- Gemma 4 31B IT is $14.62/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning and Tool use before moving production traffic.
- Provider overlap exists on GCP Vertex AI and OpenRouter; start route-level A/B tests there.
- Claude Sonnet 4.5 is $14.62/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Sonnet 4.5 adds Reasoning and Tool use in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-29 | 2026-03-31 |
| Context window | 200k | 256k |
| Parameters | — | 31B |
| Architecture | Decoder Only | - |
| License | Proprietary | Apache 2.0OSI-approved |
| Openness | Proprietary | Open source |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | 2025-12 | 2025-01 |
Pricing and availability
| Pricing attribute | Claude Sonnet 4.5 | Gemma 4 31B IT |
|---|---|---|
| Input price |
| $0.13/1M tokens |
| Output price |
| $0.38/1M tokens |
| Providers |
Capabilities
| Capability | Claude Sonnet 4.5 | Gemma 4 31B IT |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Claude Sonnet 4.5 | Gemma 4 31B IT |
|---|---|---|
| MMLU PRO | 86.0 | 85.2 |
| Google-Proof Q&A | 83.4 | 84.3 |
Deep dive
On shared benchmark coverage, MMLU PRO has Claude Sonnet 4.5 at 86 and Gemma 4 31B IT at 85.2, with Claude Sonnet 4.5 ahead by 0.8 points; Google-Proof Q&A has Claude Sonnet 4.5 at 83.4 and Gemma 4 31B IT at 84.3, with Gemma 4 31B IT ahead by 0.9 points. The largest visible gap is 0.9 points on Google-Proof Q&A, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on reasoning mode: Claude Sonnet 4.5 and tool use: Claude Sonnet 4.5. Both models share vision, multimodal input, function calling, and structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Claude Sonnet 4.5 lists tiered pricing: 0-200,001t is $3/1M input and $15/1M output; 200,001t+ is $6/1M input and $22.50/1M output, while Gemma 4 31B IT lists $0.13/1M input and $0.38/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Gemma 4 31B IT lower by about $6.39 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 8 providers versus 5, so concentration risk also matters.
Choose Claude Sonnet 4.5 when reasoning depth and broader provider choice are central to the workload. Choose Gemma 4 31B IT when long-context analysis, larger context windows, and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Claude Sonnet 4.5 or Gemma 4 31B IT?
Gemma 4 31B IT supports 256k tokens, while Claude Sonnet 4.5 supports 200k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Claude Sonnet 4.5 or Gemma 4 31B IT?
Claude Sonnet 4.5 lists tiered pricing: 0-200,001t is $3/1M input and $15/1M output; 200,001t+ is $6/1M input and $22.50/1M output. Gemma 4 31B IT lists $0.13/1M input and $0.38/1M output tokens on the cheapest tracked provider. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is Claude Sonnet 4.5 or Gemma 4 31B IT open source?
Claude Sonnet 4.5 is listed under Proprietary. Gemma 4 31B IT is listed under Apache 2.0. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Claude Sonnet 4.5 or Gemma 4 31B IT?
Both Claude Sonnet 4.5 and Gemma 4 31B IT expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for multimodal input, Claude Sonnet 4.5 or Gemma 4 31B IT?
Both Claude Sonnet 4.5 and Gemma 4 31B IT expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Claude Sonnet 4.5 and Gemma 4 31B IT?
Claude Sonnet 4.5 is available on Microsoft Foundry, Anthropic, Snowflake Cortex, GCP Vertex AI, and AWS Bedrock. Gemma 4 31B IT is available on Google AI Studio, GCP Vertex AI, OpenRouter, Together AI, and Novita AI. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-06-15. Data sourced from public model cards and provider documentation.