GPT-5.5 Pro vs Grok 4
GPT-5.5 Pro (2026) and Grok 4 (2026) are frontier-tier reasoning models from OpenAI and xAI. GPT-5.5 Pro ships a 1M-token context window, while Grok 4 ships a 256k-token context window. On SWE-bench Verified, GPT-5.5 Pro leads by 12 pts. On pricing, Grok 4 costs $3/1M input tokens versus $30/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Grok 4 is ~900% cheaper at $3/1M; pay for GPT-5.5 Pro only for coding workflow support.
Specs
| Released | 2026-04-23 | 2026-03-01 |
| Context window | 1M | 256k |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | - | - |
Pricing and availability
| GPT-5.5 Pro | Grok 4 | |
|---|---|---|
| Input price | $30/1M tokens | $3/1M tokens |
| Output price | $180/1M tokens | $15/1M tokens |
| Providers |
Capabilities
| GPT-5.5 Pro | Grok 4 | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
| Benchmark | GPT-5.5 Pro | Grok 4 |
|---|---|---|
| SWE-bench Verified | 88.7 | 76.7 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has GPT-5.5 Pro at 88.7 and Grok 4 at 76.7, with GPT-5.5 Pro ahead by 12 points. The largest visible gap is 12 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 Pro, function calling: GPT-5.5 Pro, and tool use: GPT-5.5 Pro. Both models share multimodal input, reasoning mode, structured outputs, and code execution, 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 Pro lists $30/1M input and $180/1M output tokens, while Grok 4 lists $3/1M input and $15/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok 4 lower by about $68.40 per million blended tokens. Availability is 1 providers versus 3, so concentration risk also matters.
Choose GPT-5.5 Pro when coding workflow support and larger context windows are central to the workload. Choose Grok 4 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 Pro or Grok 4?
GPT-5.5 Pro supports 1M tokens, while Grok 4 supports 256k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, GPT-5.5 Pro or Grok 4?
Grok 4 is cheaper on tracked token pricing. GPT-5.5 Pro costs $30/1M input and $180/1M output tokens. Grok 4 costs $3/1M input and $15/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GPT-5.5 Pro or Grok 4 open source?
GPT-5.5 Pro is listed under Proprietary. Grok 4 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 Pro or Grok 4?
GPT-5.5 Pro 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 Pro or Grok 4?
Both GPT-5.5 Pro and Grok 4 expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Where can I run GPT-5.5 Pro and Grok 4?
GPT-5.5 Pro is available on OpenAI API. Grok 4 is available on Microsoft Foundry, OpenRouter, and Replicate API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-04-24. Data sourced from public model cards and provider documentation.