LLM Comparison
GPT-5.5 Pro vs Grok 4.1 Fast
Side-by-side specs, pricing & capabilities · Updated April 2026
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2/6 modelsSame tier:
| Organization | ||
| OpenTools Score | 97 0.9 | |
| Family | GPT | Grok |
| Status | Current | Current |
| Release Date | Apr 2026 | Nov 2025 |
| Context Window | 1.1M tokens | 2.0M tokens |
| Input Price | $30.00/M tokens | $0.20/M tokens |
| Output Price | $180.00/M tokens | $0.50/M tokens |
| Pricing Notes | No cached input discount. Long context (>272K tokens): 2x input, 1.5x output. Batch API: 50% discount. Regional processing: 10% uplift. | Cache read: $0.0500/M tokens |
| Capabilities | textvisioncodetool-useextended-thinkingweb-search | textvisioncode |
| Training Cutoff | December 2025 | — |
| Max Output | 128K tokens | 30K tokens |
| API Identifier | openai/gpt-5.5-pro | x-ai/grok-4.1-fast |
| Benchmarks | ||
| FrontierMath Tier 4 | 39.6openai | — |
| FrontierMath Tier 1-3 | 52.4openai | — |
| HLE (with tools) | 57.2openai | — |
| HLE (no tools) | 43.1openai | — |
| BrowseComp | 90.1openai | — |
| GeneBench | 33.2openai | — |
| GDPval | 82.3openai | — |
| Investment Banking Modeling | 88.6openai | — |
| View GPT-5.5 Pro | View Grok 4.1 Fast | |
Cost Calculator
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| Model | Input | Output | Total / mo | vs Best |
|---|---|---|---|---|
| Grok 4.1 FastCheapest | $0.20 | $0.25 | $0.45 | — |
| GPT-5.5 Pro | $30.00 | $90.00 | $120.00 | +26567% |
OpenAI
GPT-5.5 Pro
GPT-5.5 Pro uses more compute to think harder and provide consistently better answers than GPT-5.5. Designed for the toughest problems, some requests may take several minutes. It excels at FrontierMath Tier 4 (39.6%) and BrowseComp (90.1%), offering the highest intelligence available from OpenAI at a premium price point.
xAI
Grok 4.1 Fast
Grok 4.1 Fast is a multimodal llm from xAI. Supports up to 2,000,000 token context window. Available from $0.20/M input tokens.
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