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GPT-5.5 Instant vs Grok 4.5
GPT-5.5 Instant (OpenAI) and Grok 4.5 (xAI) compared on benchmarks, pricing, context window, and use-case rankings.
- Grok 4.5 ranks higher for coding (89th vs 77th percentile).
| Attribute | GPT-5.5 Instant | Grok 4.5 |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | — | 154 |
| Coding | 77 | 89 |
| Math | — | 84 |
| Reasoning & Knowledge | 42 | 68 |
| Agentic & Tools | 19 | 74 |
| Specifications | ||
| Developer | OpenAI | xAI |
| Family | GPT | Grok |
| Released | May 5, 2026 | Jul 8, 2026 |
| Parameters | — | — |
| Availability | API access | API access |
| Context window | — | 500K |
| Price — $/M input | — | $2.00 |
| Price — $/M output | — | $6.00 |
| Inputs | — | text, image, file |
| Outputs | — | text |
| Benchmarks | ||
| GPQA Diamond | 85% | 93% |
| Humanity's Last Exam | 20% | 40% |
| SciCode | 50% | 54% |
| τ²-bench | 49% | — |
| AIME 2024/2025 | — | 98% |
| APEX | — | 34% |
| ARC-AGI | — | 87% |
| ARC-AGI-2 | — | 53% |
| SimpleBench | — | 70% |
| SimpleQA Verified | — | 54% |
| WebDev Arena | — | 1551 |
| WeirdML | — | 46% |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Which is better for coding, GPT-5.5 Instant or Grok 4.5?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Grok 4.5 ranks higher — 89th vs 77th percentile among the models tracked on Model Beat.
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Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.