Claude 3.5 Sonnet vs Gemini 2.5 Flash
Claude 3.5 Sonnet (2024) and Gemini 2.5 Flash (2025) are frontier reasoning models from Anthropic and Google DeepMind. Claude 3.5 Sonnet ships a 200K-token context window, while Gemini 2.5 Flash ships a 1M-token context window. On MMLU PRO, Gemini 2.5 Flash leads by 3.7 pts. On pricing, Gemini 2.5 Flash costs $0.3/1M input tokens versus $3/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Gemini 2.5 Flash is ~900% cheaper at $0.3/1M; pay for Claude 3.5 Sonnet only for coding workflow support.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-06-20 | 2025-06-17 |
| Context window | 200K | 1M |
| Parameters | 70B | — |
| Architecture | decoder only | decoder only |
| License | Unknown | Proprietary |
| Knowledge cutoff | 2024-04 | 2025-01 |
Pricing and availability
| Pricing attribute | Claude 3.5 Sonnet | Gemini 2.5 Flash |
|---|---|---|
| Input price | $3/1M tokens | $0.3/1M tokens |
| Output price | $15/1M tokens | $2.5/1M tokens |
| Providers |
Capabilities
| Capability | Claude 3.5 Sonnet | Gemini 2.5 Flash |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | No | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
Benchmarks
| Benchmark | Claude 3.5 Sonnet | Gemini 2.5 Flash |
|---|---|---|
| MMLU PRO | 77.2 | 80.9 |
| HumanEval | 92.0 | 90.1 |
| LiveCodeBench | 48.7 | 76.2 |
| Chatbot Arena | 1340.0 | 1320.0 |
| Massive Multi-discipline Multimodal Understanding | 68.3 | 79.7 |
| Aider Polyglot | 51.6 | 55.1 |
Deep dive
On shared benchmark coverage, MMLU PRO has Claude 3.5 Sonnet at 77.2 and Gemini 2.5 Flash at 80.9, with Gemini 2.5 Flash ahead by 3.7 points; HumanEval has Claude 3.5 Sonnet at 92 and Gemini 2.5 Flash at 90.1, with Claude 3.5 Sonnet ahead by 1.9 points; LiveCodeBench has Claude 3.5 Sonnet at 48.7 and Gemini 2.5 Flash at 76.2, with Gemini 2.5 Flash ahead by 27.5 points. The largest visible gap is 27.5 points on LiveCodeBench, 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 3.5 Sonnet and tool use: Gemini 2.5 Flash. 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 3.5 Sonnet lists $3/1M input and $15/1M output tokens, while Gemini 2.5 Flash lists $0.3/1M input and $2.5/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Gemini 2.5 Flash lower by about $5.64 per million blended tokens. Availability is 6 providers versus 4, so concentration risk also matters.
Choose Claude 3.5 Sonnet when coding workflow support and broader provider choice are central to the workload. Choose Gemini 2.5 Flash when coding workflow support, 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 3.5 Sonnet or Gemini 2.5 Flash?
Gemini 2.5 Flash supports 1M tokens, while Claude 3.5 Sonnet 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 3.5 Sonnet or Gemini 2.5 Flash?
Gemini 2.5 Flash is cheaper on tracked token pricing. Claude 3.5 Sonnet costs $3/1M input and $15/1M output tokens. Gemini 2.5 Flash costs $0.3/1M input and $2.5/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude 3.5 Sonnet or Gemini 2.5 Flash open source?
Claude 3.5 Sonnet is listed under Unknown. Gemini 2.5 Flash is listed under Proprietary. 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 3.5 Sonnet or Gemini 2.5 Flash?
Both Claude 3.5 Sonnet and Gemini 2.5 Flash 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 3.5 Sonnet or Gemini 2.5 Flash?
Both Claude 3.5 Sonnet and Gemini 2.5 Flash 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 3.5 Sonnet and Gemini 2.5 Flash?
Claude 3.5 Sonnet is available on GCP Vertex AI, AWS Bedrock, Anthropic, OpenRouter, and Microsoft Foundry. Gemini 2.5 Flash is available on Google AI Studio, GCP Vertex AI, Replicate API, and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.