Gemini 3.1 Pro Preview vs o3-pro
Gemini 3.1 Pro Preview (2026) and o3-pro (2025) are frontier reasoning models from Google DeepMind and OpenAI. Gemini 3.1 Pro Preview ships a 1m-token context window, while o3-pro ships a 200k-token context window. On Google-Proof Q&A, Gemini 3.1 Pro Preview leads by 10.3 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 fits 5x more tokens; pick it for long-context work and o3-pro for tighter calls.
Decision scorecard
Local evidence first| Signal | Gemini 3.1 Pro Preview | o3-pro |
|---|---|---|
| Best for | multimodal apps, tool-calling agents, and long-context analysis | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1m | 200k |
| Cheapest output | $12/1M tokens | $80/1M tokens |
| Provider routes | 5 tracked | 3 tracked |
| Shared benchmarks | Google-Proof Q&A leader | 1 shared |
Decision tradeoffs
- Gemini 3.1 Pro Preview holds a shared-benchmark lead on Google-Proof Q&A, ahead by 10.3 points.
- Gemini 3.1 Pro Preview has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Gemini 3.1 Pro Preview has the lower cheapest tracked output price at $12/1M tokens.
- Gemini 3.1 Pro Preview has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags Gemini 3.1 Pro Preview for Coding, RAG, and Agents.
- o3-pro uniquely exposes Reasoning in local model data.
- Local decision data tags o3-pro 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 3.1 Pro Preview
$4,600
Cheapest tracked route/tier: Google AI Studio
o3-pro
$36,000
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $31,400. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
- o3-pro is $68/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- o3-pro adds Reasoning in local capability data.
- Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
- Gemini 3.1 Pro Preview is $68/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-19 | 2025-06-10 |
| Context window | 1m | 200k |
| 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 | 2025-01 | 2025-08 |
Pricing and availability
| Pricing attribute | Gemini 3.1 Pro Preview | o3-pro |
|---|---|---|
| Input price |
| $20/1M tokens |
| Output price |
| $80/1M tokens |
| Providers |
Capabilities
| Capability | Gemini 3.1 Pro Preview | o3-pro |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Gemini 3.1 Pro Preview | o3-pro |
|---|---|---|
| Google-Proof Q&A | 94.3 | 84.0 |
Continue comparing
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.