GPT-5 thinking vs Claude 4.5 Sonnet (thinking)

Detailed comparison of capabilities, features, and performance.

Feature
GPT-5 thinking
Claude 4.5 Sonnet (thinking)
Model Image
GPT-5 thinking
Claude 4.5 Sonnet (thinking)
AI Lab
OpenAI
Anthropic
Context Size
272,000 tokens
1,000,000 tokens
Max Output Size
128,000 tokens
200,000 tokens
Frontier Model
Yes
Yes
Vision Support
Yes
Yes
Description
OpenAI's flagship model configured for longer thinking.
The latest Claude 4.5 Sonnet model from Anthropic with maximum reasoning enabled, 200k reasoning tokens in 1M context.

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