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GPT-5.5 vs Grok 4.5

GPT-5.5 leads in 2 of 8 categories

Arena ELO

Tie

Cheaper

GPT-5.5

Faster

Tie

Detailed Comparison

CategoryGPT-5.5Grok 4.5
ProviderOpenAI xAI
Context Window128K 128K
Input Price ($/1M)$5 WINN/A
Output Price ($/1M)$30 WINN/A
Arena ELON/A N/A
CodingN/A N/A
ReasoningN/A N/A
Speed (tokens/sec)N/A N/A
Open SourceNo No

Frequently Asked Questions

Which has a larger context window?

GPT-5.5 supports 128K context, while Grok 4.5 supports 128K.

Is GPT-5.5 or Grok 4.5 open source?

GPT-5.5 is proprietary. Grok 4.5 is proprietary.