Start with the right comparison
A fair test should use the same task, context, tools and success criteria. Comparing a single benchmark number can hide important differences in reliability and workflow.
Where Claude Opus 5.5 stands
Anthropic launched Claude Opus 5.5 on September 22, 2026 and says it targets agentic coding, computer use and knowledge work. Anthropic reports lower typical operating cost than Opus 5 and API pricing of $4 per million input tokens and $20 per million output tokens.
Where ChatGPT fits
ChatGPT combines models with tools and workflows. The useful question is whether the particular ChatGPT configuration you have is better suited to your task than Claude's current model and tools.
For coding
Test the same repository task. Measure code understanding, safe edits, test execution, tool use and recovery from mistakes rather than relying only on benchmark claims.
For students and writing
Compare instruction following, document handling, editing quality and citation workflows. Verify important claims and follow your institution's AI rules.
For API developers
Token price matters, but latency, rate limits, context, tool calling and reliability also affect the real cost of a production workflow.
How to compare them yourself
Create five representative tasks from your real work, run both systems under comparable conditions, record failures and time, then choose based on evidence relevant to your workflow.