Head-to-head

GPT-5.5 vs Grok 4.3

How GPT-5.5 (OpenAI) and Grok 4.3 (xAI) compare on price, context window and best-fit use case.

In short: GPT-5.5 is best for highest-stakes reasoning, complex agents, and frontier coding tasks where capability outweighs cost, while Grok 4.3 suits reasoning and agentic tasks needing current/real-time info and low output costs. On price it's $5.00 vs $1.25 ($0.20 cached) per 1M input tokens; on context, ~1.05M tokens (128K max output) vs 1M tokens.

Verdict

GPT-5.5 is the more capable pick (Bq score 95 vs 88). Choose Grok 4.3 if budget leads: its input price is $1.25 ($0.20 cached) per 1M vs $5.00.

SpecGPT-5.5Grok 4.3
DeveloperOpenAIxAI
Context window~1.05M tokens (128K max output)1M tokens
Input price /1M$5.00$1.25 ($0.20 cached)
Output price /1M$30.00$2.50
Modalitiestext, imagetext, image
Best forHighest-stakes reasoning, complex agents, and frontier coding tasks where capability outweighs cost.Reasoning and agentic tasks needing current/real-time info and low output costs.

GPT-5.5

  • State-of-the-art reasoning and agentic workflows
  • 1M+ context window
  • Strong coding and tool use
  • Multimodal (text + image input)
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Grok 4.3

  • Very competitive output pricing
  • Configurable reasoning effort
  • Real-time X and web search integration
  • 1M context
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