Automated page. Written and translated automatically by AI and checked against the sources by software; no human editor. SI-IQ is an index built from public benchmark results, not an IQ test. How it works
How smart is GPT-5.5 Pro?
GPT-5.5 Pro is a model from OpenAI, released on Apr 23, 2026. Its SI-IQ is 139 (90% interval 135–142), estimated from 5 benchmark results by 1 independent evaluators.
This model has fewer than 5 independent benchmark results or fewer than 2 different evaluators, so it is shown but not ranked.
Facts
- Developer
- OpenAI
- Released
- Apr 23, 2026
- Access
- API access
- Benchmarks used
- 5 results from 1 evaluators
Ability by area (SI-IQ, 90% interval)
Every benchmark result we used
Each score is one value exactly as the source published it: for Epoch AI the best of its run settings, for OpenRouter the median hosting provider (the developer's own hosting when it ran the test). “Implied SI-IQ” is the ability that this single result points to; the overall SI-IQ is their precision-weighted average.
| Benchmark | Score | Evaluated by | Source |
|---|---|---|---|
| Chess Puzzles | 62.0% | Epoch AI | Epoch AI Benchmarking Hub · data file |
| FrontierMath Tier 4 | 78.0% | Epoch AI | Epoch AI Benchmarking Hub · data file |
| FrontierMath Tiers 1–3 | 87.7% | Epoch AI | Epoch AI Benchmarking Hub · data file |
| OTIS Mock AIME 2024–2025 | 100.0% | Epoch AI | Epoch AI Benchmarking Hub · data file |
| GPQA Diamond | 93.9% | Epoch AI | Epoch AI Benchmarking Hub · data file |
Computed with SI-IQ method version 1.0.0. Read the full methodology
Data sources: Epoch AI, ‘Capabilities & benchmarking’ (CC BY 4.0).