Claude Sonnet 4.5 vs gpt-5-nano

Anthropic Claude Claude Sonnet 4.5OpenAI gpt-5-nano
VendorAnthropic ClaudeOpenAI
Context window1,000,000400,000
Max output64,000128,000
ReasoningYesYes
Tool callingYesYes
File inputYesYes
Inputtext, imagetext, image
Outputtexttext
Released2025-09-292025-08-07