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 | 3 tracked | 4 tracked |
| Shared benchmarks | MMLU PRO leader | 5 rows |
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.
- o3 Mini has broader tracked provider coverage for fallback and procurement flexibility.
- 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 |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| 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 |
| Function calling | Yes | Yes |
| 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 |
Deep dive
On shared benchmark coverage, MMLU PRO has GPT-5.5 at 88.1 and o3 Mini at 79.1, with GPT-5.5 ahead by 9 points; SWE-bench Verified has GPT-5.5 at 82.6 and o3 Mini at 49.3, with GPT-5.5 ahead by 33.3 points; Google-Proof Q&A has GPT-5.5 at 93.6 and o3 Mini at 79.7, with GPT-5.5 ahead by 13.9 points. The largest visible gap is 33.3 points on SWE-bench Verified, 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 vision: GPT-5.5 and multimodal input: GPT-5.5. Both models share reasoning mode, function calling, tool use, 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, GPT-5.5 lists tiered pricing: 0-272K input tokens is $5/1M input and $30/1M output; 272K+ input tokens is $8/1M input and $36/1M output, while o3 Mini lists $1.10/1M input and $4.40/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts o3 Mini lower by about $10.41 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 3 providers versus 4, so concentration risk also matters.
Choose GPT-5.5 when coding workflow support and larger context windows are central to the workload. Choose o3 Mini when coding workflow support, lower input-token cost, 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, GPT-5.5 or o3 Mini?
GPT-5.5 supports 1.05m tokens, while o3 Mini supports 200k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is cheaper, GPT-5.5 or o3 Mini?
GPT-5.5 lists tiered pricing: 0-272K input tokens is $5/1M input and $30/1M output; 272K+ input tokens is $8/1M input and $36/1M output. o3 Mini lists $1.10/1M input and $4.40/1M output tokens on the cheapest tracked provider. 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 GPT-5.5 or o3 Mini open source?
GPT-5.5 is listed under Proprietary. o3 Mini 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, GPT-5.5 or o3 Mini?
GPT-5.5 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, GPT-5.5 or o3 Mini?
GPT-5.5 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run GPT-5.5 and o3 Mini?
GPT-5.5 is available on OpenAI API, OpenRouter, and Vercel AI Gateway. o3 Mini is available on OpenRouter, Azure OpenAI, OpenAI API, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-08. Data sourced from public model cards and provider documentation.