Claude Sonnet 5.5 vs Claude Opus 5.5
Claude Sonnet 5.5 and Claude Opus 5.5 are within three points on the Models at Work leaderboard, which we treat as a tie (86 vs 85). 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 Sonnet 5.5 · Anthropic | Claude Opus 5.5 · Anthropic | |
|---|---|---|
| Leaderboard rank | #1 | #2 |
| Score (0–100) | 86 | 85 |
| Tier | Workhorse | Frontier |
| Price per 1M tokens | $2 in · $10 out | $4 in · $20 out |
| Context window | 1M | 1M |
| Open weights | No | No |
| Artificial Analysis Intelligence Index | 56 | 58 |
| Arena text score | — | 1507 |
| Humanity's Last Exam, Diamond (Scale) | — | 55.0 |
| Epoch Capabilities Index | — | 167 |
| Best for | Production coding assistants, High-volume agents, Default model for most teams | Agentic coding, Long-running agents, Enterprise knowledge work |
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.
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.
What practitioners say
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.
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.
Questions people ask
Which is better, Claude Sonnet 5.5 or Claude Opus 5.5?
Claude Sonnet 5.5 and Claude Opus 5.5 are within three points on the Models at Work leaderboard, which we treat as a tie (86 vs 85). 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 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.
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.
Which is cheaper, Claude Sonnet 5.5 or Claude Opus 5.5?
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 11, 2026). 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 11, 2026).
Scores come from the Models at Work leaderboard: Score is 0 to 100 and computed, not typed: 55% independent evals (Artificial Analysis, Arena, Scale SEAL, Epoch, each scaled against its natural floor and the best score in this table, then averaged), 15% blended price on a fixed log scale ($0.05 per million is 100, $60 is 0), 15% practitioner sentiment from Signals and community threads, 15% operational fit (context window, open weights). A missing component drops out and the rest are reweighted. A model with no independent eval yet is provisional and ranks below every measured one. Within three points is a tie. Vendor-published figures are labelled and never counted. Prices are vendor list prices where published; blended figures assume three input tokens per output token.