OpenAI announces o3 retirement from ChatGPT and shares benchmark scores

OpenAI announced on May 28, 2026, that the o3 model will be retired from ChatGPT on August 26, 2026, following a 90-day sunset period. While the API remains available indefinitely, users are advised to migrate to successors like o4 or the GPT-5 family for complex reasoning and coding tasks.

The article details o3's benchmark performance prior to its retirement:

• AIME: 96.7% on 2024 and 88.9% on 2025.
• FrontierMath: 25.2%, approximately 12x better than previous bests at launch.
• GPQA Diamond: 87.7%, surpassing average human expert performance of ~70%.
• SWE-bench Verified: 71.7%, a 22.8 percentage point improvement over o1.

This guide provides context for interpreting these scores relative to newer models like GPT-5 and o4, noting that while o3 remains strong, it is no longer the frontier for all benchmarks.