GPT-5.5 (xHigh): benchmark results

GPT-5.5 evaluated at the xhigh reasoning-effort setting. Provider: OpenAI. Released 2026-04-23. Access: API.

Unified ELO 1753 ± 1, rank #25 of 1761 rated models, from 201 benchmark results.

Strongest benchmark results

BenchmarkScoreMetricPercentile
ALE-Bench1942.97Performance (Self-Refine x1) (self-reported)100
AlmanBench - Acceptance95.43Acceptance Rate (%)100
ClawProBench67.9Final Score (self-reported)100
GRIPS96.4Accuracy (%)100
GRIPS-hard87.3Accuracy (%)100
LLM2014 Logic 2026-0483.96Median Score100
LLM2014 Logic 2026-0580.47Median Score100
LLM2014 Logic 2026-0680.47Median Score100
LLM2014 Logic 2026-0777.46Median Score100
LLM2014 Logic 2026-0873.89Median Score100
LiveBench81.28LiveBench average (self-reported)100
MathArena - APEX Shortlist 202598.4Accuracy (%)100

Interactive version: theaggregate.ai/model?slug=gpt-5-5-xhigh · How It Works · Data refreshed daily, snapshot 2026-09-05.