Claude Fable 5 vs GPT-5.5 Instant
Claude Fable 5 (Anthropic) and GPT-5.5 Instant (OpenAI) compared on benchmarks, pricing, context window, and use-case rankings.
- Claude Fable 5 leads on overall intelligence (ECI 163 vs 143).
- Claude Fable 5 ranks higher for coding (96th vs 78th percentile).
| Attribute | Claude Fable 5 | GPT-5.5 Instant |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 163 | 143 |
| Coding | 96 | 78 |
| Math | 96 | 7 |
| Reasoning & Knowledge | 89 | 33 |
| Agentic & Tools | 96 | 16 |
| Specifications | ||
| Developer | Anthropic | OpenAI |
| Family | Claude | GPT |
| Released | Jun 9, 2026 | May 5, 2026 |
| Parameters | — | — |
| Availability | API access | API access |
| Context window | 1M | — |
| Price — $/M input | $10.00 | — |
| Price — $/M output | $50.00 | — |
| Inputs | text, image, file | — |
| Outputs | text | — |
| Benchmarks | ||
| AIME 2024/2025 | 100% | 68% |
| APEX | 45% | — |
| ARC-AGI | 99% | — |
| ARC-AGI-2 | 89% | — |
| GPQA Diamond | 86% | 83% |
| Humanity's Last Exam | 56% | 20% |
| SciCode | 61% | 53% |
| SimpleBench | 82% | — |
| SimpleQA Verified | 71% | 38% |
| WebDev Arena | 1626 | — |
| WeirdML | 92% | — |
| τ²-bench | 99% | 49% |
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
Is Claude Fable 5 better than GPT-5.5 Instant?
On Epoch AI's Capabilities Index, Claude Fable 5 scores higher (163) than GPT-5.5 Instant (143). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is better for coding, Claude Fable 5 or GPT-5.5 Instant?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Claude Fable 5 ranks higher — 96th vs 78th 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.