Claude Opus 5.5 vs Claude Sonnet 5.5
Claude Opus 5.5 scores higher on the Models at Work leaderboard (91 vs 84 out of 100). Claude Sonnet 5.5 is about 2.0× cheaper per blended million tokens ($4 vs $8). On Artificial Analysis' independent Intelligence Index, Claude Opus 5.5 leads 58 to 56.
| Claude Opus 5.5 · Anthropic | Claude Sonnet 5.5 · Anthropic | |
|---|---|---|
| Leaderboard rank | #1 | #4 |
| Score (0–100) | 91 | 84 |
| Tier | Frontier | Workhorse |
| Price per 1M tokens | $4 in · $20 out | $2 in · $10 out |
| Context window | 1M | 1M |
| Open weights | No | No |
| Artificial Analysis Intelligence Index | 58 | 56 |
| Arena text score | 1507 | — |
| Humanity's Last Exam, Diamond (Scale) | 55.0 | — |
| Epoch Capabilities Index | 167 | — |
| Best for | Agentic coding, Long-running agents, Enterprise knowledge work | Production coding assistants, High-volume agents, Default model for most teams |
Choose Claude Opus 5.5 if…
- you need agentic coding
- you need long-running agents
- you need enterprise knowledge work
The model people actually ship agents on: top of the independent index, a price that does not need a budget meeting, and a community that complains mainly about how much it has to be used.
Caveats: Arena puts Gemini 4 Argon ahead on chat preference; the gap is inside two scores' error bars.
Choose Claude Sonnet 5.5 if…
- you need production coding assistants
- you need high-volume agents
- you need default model for most teams
The value pick of the table: second on the index at a fifth of the Opus price, and the fastest of the top five.
What practitioners say
Claude Opus 5.5: The launch thread was the biggest Claude thread of the year on Hacker News, a port of the TypeScript compiler to Rust credited the model with a working build in ten hours, and a Vals AI materials-discovery run used it for agentic simulation. A 'has it been nerfed yet' tracker is the most-upvoted scepticism.
Claude Sonnet 5.5: Less discussed than its siblings because it just works; the October cache-read price cut to $0.10 per million was the news.
Questions people ask
Which is better, Claude Opus 5.5 or Claude Sonnet 5.5?
Claude Opus 5.5 scores higher on the Models at Work leaderboard (91 vs 84 out of 100). Claude Sonnet 5.5 is about 2.0× cheaper per blended million tokens ($4 vs $8). On Artificial Analysis' independent Intelligence Index, Claude Opus 5.5 leads 58 to 56.
When should I choose Claude Opus 5.5 over Claude Sonnet 5.5?
Choose Claude Opus 5.5 for agentic coding, long-running agents, enterprise knowledge work. The model people actually ship agents on: top of the independent index, a price that does not need a budget meeting, and a community that complains mainly about how much it has to be used.
When should I choose Claude Sonnet 5.5 over Claude Opus 5.5?
Choose Claude Sonnet 5.5 for production coding assistants, high-volume agents, default model for most teams. The value pick of the table: second on the index at a fifth of the Opus price, and the fastest of the top five.
Which is cheaper, Claude Opus 5.5 or Claude Sonnet 5.5?
Claude Opus 5.5 costs $4 per million input tokens and $20 per million output tokens on Anthropic's list price (Claude pricing, read Oct 10, 2026). Claude Sonnet 5.5 costs $2 per million input tokens and $10 per million output tokens on Anthropic's list price (Claude pricing, read Oct 10, 2026).
Scores come from the Models at Work leaderboard: Score is 0 to 100: 50% independent evals normalised within this table, 20% price-performance, 15% practitioner sentiment from Signals and community threads, 15% operational fit (context, speed, availability, open weights). Models within three points are a tie in practice. Vendor-published figures are labelled as such and never counted as independent. Prices are vendor list prices where published; blended figures assume three input tokens per output token.