GPT-5.5 vs Grok 4.20
The comparison
On LM Arena, GPT-5.5 scores higher (1482 Elo vs 1472 Elo), from a smaller review base (47,572 vs 61,762 Arena votes).
As of Jul 30, 2026, GPT-5.5 is rated 1482 Elo on LM Arena (47,572 Arena votes); Grok 4.20 is rated 1472 Elo on LM Arena (61,762 Arena votes). No source is blended; each stands on its own.