GPT-5.5 vs o3 Mini
GPT-5.5 (2026) and o3 Mini (2025) are frontier-tier reasoning models from OpenAI. GPT-5.5 ships a 1.05m-token context window, while o3 Mini ships a 200k-token context window. On MMLU PRO, GPT-5.5 leads by 9 pts. On pricing, GPT-5.5 ranges from $5 to $8/1M input tokens by tier; o3 Mini costs $1.10/1M input tokens. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
GPT-5.5 fits 5x more tokens; pick it for long-context work and o3 Mini for tighter calls.
Decision scorecard
Local evidence first| Signal | GPT-5.5 | o3 Mini |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, tool-calling agents, and provider-routed production |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1.05m | 200k |
| Cheapest output | $30/1M tokens | $4.40/1M tokens |
| Provider routes | 4 tracked | 4 tracked |
| Shared benchmarks | MMLU PRO leader | 5 shared |
Decision tradeoffs
- GPT-5.5 holds a shared-benchmark lead on MMLU PRO, ahead by 9 points.
- GPT-5.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.5 uniquely exposes Vision and Multimodal in local model data.
- Local decision data tags GPT-5.5 for Coding, RAG, and Agents.
- o3 Mini has the lower cheapest tracked output price at $4.40/1M tokens.
- Local decision data tags o3 Mini 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.
GPT-5.5
$11,500
Cheapest tracked route/tier: OpenAI API 0-272K input tokens
o3 Mini
$1,980
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $9,520. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter, OpenAI API, and Vercel AI Gateway; start route-level A/B tests there.
- o3 Mini is $25.60/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision and Multimodal before moving production traffic.
- Provider overlap exists on OpenAI API, OpenRouter, and Vercel AI Gateway; start route-level A/B tests there.
- GPT-5.5 is $25.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.5 adds Vision and Multimodal in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-23 | 2025-01-31 |
| Context window | 1.05m | 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 | 2025-12 | 2025-04 |
Pricing and availability
| Pricing attribute | GPT-5.5 | o3 Mini |
|---|---|---|
| Input price |
| $1.10/1M tokens |
| Output price |
| $4.40/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.5 | o3 Mini |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | 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 | GPT-5.5 | o3 Mini |
|---|---|---|
| MMLU PRO | 88.1 | 79.1 |
| SWE-bench Verified | 82.6 | 49.3 |
| Google-Proof Q&A | 93.6 | 79.7 |
| Chatbot Arena | 1488.0 | 1335.0 |
| Aider Polyglot | 88.0 | 60.4 |
Continue comparing
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.