Claude Opus 4.1
Claude Opus 4.1 is an API-only (closed weights) language model from Anthropic, released August 5, 2025. On the Epoch Capabilities Index it scores 144.8, rank 97 of 256 rated models.
Today we're releasing Claude Opus 4.1, an upgrade to Claude Opus 4 on agentic tasks, real-world coding, and reasoning. We plan to release substantially larger improvements to our models in the coming weeks. Opus 4.1 is now available to paid Claude users and in Claude Code.
Check it against your own PC →
Strengths by category
ModelTape's 0–100 fit on Epoch AI benchmark results.
| Category | Score | Based on |
|---|---|---|
| Reasoning | 16.1 | SimpleBench, Mystery Game Puzzles, Humanity's Last Exam |
| Math | 25.5 | OTIS Mock AIME 2024-2025, FrontierMath-Tiers-1-3-v2-Private, FrontierMath-Tier-4-v2-Private |
| Coding | 44.0 | Terminal Bench, SWE-bench Verified |
Benchmark results
| Benchmark (Epoch AI) | Score |
|---|---|
| SWE-bench Verified | 73.3% |
| GPQA Diamond | 72.6% |
| OTIS Mock AIME | 68.9% |
| SimpleBench | 52.0% |
| Terminal-Bench | 38.0% |
| FrontierMath (Tiers 1–3) | 13.3% |
| Mystery Game Puzzles | 13.0% |
| Humanity's Last Exam | 11.5% |
| EBR-bench | 7.9% |
| FrontierMath-Tier-4-v2-Private | 2.4% |
Links
Announcement · Epoch AI benchmarks
Models with a similar score
Kimi K2.5 · Inkling · Qwen3.5 397B-A17B · Qwen3.7-Plus · MiniMax-M3 · Claude Sonnet 4.5 · o3-pro · Qwen 3.5 Plus (hosted 397B-A17B)
More from Anthropic
Claude Fable 5.2 · Claude Haiku 5.5 · Claude Sonnet 5.5 · Claude Opus 5.5 · Claude Fable 5.1 · Claude Opus 5 · Claude Sonnet 5 · Claude Fable 5