Gemini 3 Flash vs Gemini 3.1 Pro Preview
Gemini 3 Flash (2025) and Gemini 3.1 Pro Preview (2026) are general-purpose language models from Google DeepMind. Gemini 3 Flash ships a 1m-token context window, while Gemini 3.1 Pro Preview ships a 1m-token context window. On SWE-bench Verified, Gemini 3.1 Pro Preview leads by 2.6 pts. 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 Gemini 3 Flash when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | Gemini 3 Flash | Gemini 3.1 Pro Preview |
|---|---|---|
| Best for | multimodal apps, tool-calling agents, and long-context analysis | 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 | $3/1M tokens | $12/1M tokens |
| Provider routes | 4 tracked | 5 tracked |
| Shared benchmarks | 4 rows | SWE-bench Verified leader |
Decision tradeoffs
- Gemini 3 Flash has the lower cheapest tracked output price at $3/1M tokens.
- Local decision data tags Gemini 3 Flash for Coding, RAG, and Agents.
- Gemini 3.1 Pro Preview leads the largest shared benchmark signal on SWE-bench Verified by 2.6 points.
- Gemini 3.1 Pro Preview has broader tracked provider coverage for fallback and procurement flexibility.
- Gemini 3.1 Pro Preview uniquely exposes Structured outputs in local model data.
- 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.
Gemini 3 Flash
$1,150
Cheapest tracked route/tier: Replicate API
Gemini 3.1 Pro Preview
$4,600
Cheapest tracked route/tier: Google AI Studio
Estimated monthly gap: $3,450. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Google AI Studio, GCP Vertex AI, and Replicate API; start route-level A/B tests there.
- Gemini 3.1 Pro Preview is $9/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Gemini 3.1 Pro Preview adds Structured outputs in local capability data.
- Provider overlap exists on Replicate API, GCP Vertex AI, and Google AI Studio; start route-level A/B tests there.
- Gemini 3 Flash is $9/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Structured outputs before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-12-17 | 2026-02-19 |
| Context window | 1m | 1m |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-01 | 2025-01 |
Pricing and availability
| Pricing attribute | Gemini 3 Flash | Gemini 3.1 Pro Preview |
|---|---|---|
| Input price |
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| Output price |
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| Providers |
Capabilities
| Capability | Gemini 3 Flash | Gemini 3.1 Pro Preview |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | No |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | No | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Gemini 3 Flash | Gemini 3.1 Pro Preview |
|---|---|---|
| SWE-bench Verified | 78.0 | 80.6 |
| Google-Proof Q&A | 90.4 | 94.3 |
| Chatbot Arena | 1467.0 | 1493.0 |
| τ-bench | 71.5 | 76.5 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has Gemini 3 Flash at 78 and Gemini 3.1 Pro Preview at 80.6, with Gemini 3.1 Pro Preview ahead by 2.6 points; Google-Proof Q&A has Gemini 3 Flash at 90.4 and Gemini 3.1 Pro Preview at 94.3, with Gemini 3.1 Pro Preview ahead by 3.9 points; Chatbot Arena has Gemini 3 Flash at 1467 and Gemini 3.1 Pro Preview at 1493, with Gemini 3.1 Pro Preview ahead by 26 points. The largest visible gap is 26 points on Chatbot Arena, 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 structured outputs: Gemini 3.1 Pro Preview. Both models share vision, multimodal input, function calling, and tool use, 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, Gemini 3 Flash lists tiered pricing: 0-200,001t is $0.50/1M input and $3/1M output; 200,001t+ is $0.50/1M input and $3/1M output, while Gemini 3.1 Pro Preview lists tiered pricing: 0-200,001t is $2/1M input and $12/1M output; 200,001t+ is $4/1M input and $18/1M output. A 70/30 input-output blend puts Gemini 3 Flash lower by about $3.75 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 4 providers versus 5, so concentration risk also matters.
Choose Gemini 3 Flash when coding workflow support and lower cheapest-tier input-token cost are central to the workload. Choose Gemini 3.1 Pro Preview when coding workflow support and broader provider choice 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, Gemini 3 Flash or Gemini 3.1 Pro Preview?
Gemini 3 Flash supports 1m tokens, while Gemini 3.1 Pro Preview supports 1m tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Gemini 3 Flash or Gemini 3.1 Pro Preview?
Gemini 3 Flash lists tiered pricing: 0-200,001t is $0.50/1M input and $3/1M output; 200,001t+ is $0.50/1M input and $3/1M output. Gemini 3.1 Pro Preview lists tiered pricing: 0-200,001t is $2/1M input and $12/1M output; 200,001t+ is $4/1M input and $18/1M output. 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 Gemini 3 Flash or Gemini 3.1 Pro Preview open source?
Gemini 3 Flash is listed under Proprietary. Gemini 3.1 Pro Preview 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, Gemini 3 Flash or Gemini 3.1 Pro Preview?
Both Gemini 3 Flash and Gemini 3.1 Pro Preview 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, Gemini 3 Flash or Gemini 3.1 Pro Preview?
Both Gemini 3 Flash and Gemini 3.1 Pro Preview 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 Gemini 3 Flash and Gemini 3.1 Pro Preview?
Gemini 3 Flash is available on Replicate API, GCP Vertex AI, Google AI Studio, and Vercel AI Gateway. Gemini 3.1 Pro Preview is available on Google AI Studio, GCP Vertex AI, OpenRouter, Replicate API, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.