Gemini 2.5 Pro vs Gemini 3.1 Pro Preview
Gemini 2.5 Pro (2025) and Gemini 3.1 Pro Preview (2026) are general-purpose language models from Google DeepMind. Gemini 2.5 Pro 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 17.4 pts. On pricing, Gemini 2.5 Pro costs $1.25/1M input tokens versus $2/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Gemini 2.5 Pro is ~60% cheaper at $1.25/1M; pay for Gemini 3.1 Pro Preview only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Gemini 2.5 Pro | Gemini 3.1 Pro Preview |
|---|---|---|
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1M | 1M |
| Cheapest output | $10/1M tokens | $12/1M tokens |
| Provider routes | 3 tracked | 4 tracked |
| Shared benchmarks | 3 rows | SWE-bench Verified leader |
Decision tradeoffs
- Gemini 2.5 Pro has the lower cheapest tracked output price at $10/1M tokens.
- Local decision data tags Gemini 2.5 Pro for Coding, RAG, and Agents.
- Gemini 3.1 Pro Preview leads the largest shared benchmark signal on SWE-bench Verified by 17.4 points.
- Gemini 3.1 Pro Preview has broader tracked provider coverage for fallback and procurement flexibility.
- 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 prices on this page.
Gemini 2.5 Pro
$3,500
Cheapest tracked route: Google AI Studio
Gemini 3.1 Pro Preview
$4,600
Cheapest tracked route: Google AI Studio
Estimated monthly gap: $1,100. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Google AI Studio, GCP Vertex AI, and OpenRouter; start route-level A/B tests there.
- Gemini 3.1 Pro Preview is $2/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Provider overlap exists on Google AI Studio, GCP Vertex AI, and OpenRouter; start route-level A/B tests there.
- Gemini 2.5 Pro is $2/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-06-17 | 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 2.5 Pro | Gemini 3.1 Pro Preview |
|---|---|---|
| Input price | $1.25/1M tokens | $2/1M tokens |
| Output price | $10/1M tokens | $12/1M tokens |
| Providers |
Capabilities
| Capability | Gemini 2.5 Pro | Gemini 3.1 Pro Preview |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | No |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
Benchmarks
| Benchmark | Gemini 2.5 Pro | Gemini 3.1 Pro Preview |
|---|---|---|
| SWE-bench Verified | 63.2 | 80.6 |
| Google-Proof Q&A | 86.4 | 94.3 |
| Chatbot Arena | 1398.0 | 1493.0 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has Gemini 2.5 Pro at 63.2 and Gemini 3.1 Pro Preview at 80.6, with Gemini 3.1 Pro Preview ahead by 17.4 points; Google-Proof Q&A has Gemini 2.5 Pro at 86.4 and Gemini 3.1 Pro Preview at 94.3, with Gemini 3.1 Pro Preview ahead by 7.9 points; Chatbot Arena has Gemini 2.5 Pro at 1398 and Gemini 3.1 Pro Preview at 1493, with Gemini 3.1 Pro Preview ahead by 95 points. The largest visible gap is 95 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 is close: both models cover vision, multimodal input, function calling, tool use, and structured outputs. That makes context budget, benchmark fit, and provider maturity more important than a simple checklist. If your application depends on one integration detail, verify it against the provider route you plan to use, not just the base model listing.
For cost, Gemini 2.5 Pro lists $1.25/1M input and $10/1M output tokens, while Gemini 3.1 Pro Preview lists $2/1M input and $12/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Gemini 2.5 Pro lower by about $1.13 per million blended tokens. Availability is 3 providers versus 4, so concentration risk also matters.
Choose Gemini 2.5 Pro when coding workflow support and lower 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 2.5 Pro or Gemini 3.1 Pro Preview?
Gemini 2.5 Pro 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 2.5 Pro or Gemini 3.1 Pro Preview?
Gemini 2.5 Pro is cheaper on tracked token pricing. Gemini 2.5 Pro costs $1.25/1M input and $10/1M output tokens. Gemini 3.1 Pro Preview costs $2/1M input and $12/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Gemini 2.5 Pro or Gemini 3.1 Pro Preview open source?
Gemini 2.5 Pro 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 2.5 Pro or Gemini 3.1 Pro Preview?
Both Gemini 2.5 Pro 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 2.5 Pro or Gemini 3.1 Pro Preview?
Both Gemini 2.5 Pro 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 2.5 Pro and Gemini 3.1 Pro Preview?
Gemini 2.5 Pro is available on Google AI Studio, GCP Vertex AI, and OpenRouter. Gemini 3.1 Pro Preview is available on Google AI Studio, GCP Vertex AI, OpenRouter, and Replicate API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.