Claude Opus 5.5 vs Kimi K3
Claude Opus 5.5 scores higher on the Models at Work leaderboard (91 vs 60 out of 100). Kimi K3 is about 3.5× cheaper per blended million tokens ($2.31 vs $8, one figure an Artificial Analysis estimate). On Artificial Analysis' independent Intelligence Index, Claude Opus 5.5 leads 58 to 44.
| Claude Opus 5.5 · Anthropic | Kimi K3 · Moonshot | |
|---|---|---|
| Leaderboard rank | #1 | #11 |
| Score (0–100) | 91 | 60 |
| Tier | Frontier | Open weights |
| Price per 1M tokens | $4 in · $20 out | $2.31 blended (estimate) |
| Context window | 1M | Not verified |
| Open weights | No | Yes |
| Artificial Analysis Intelligence Index | 58 | 44 |
| Arena text score | 1507 | 1488 |
| Humanity's Last Exam, Diamond (Scale) | 55.0 | — |
| Epoch Capabilities Index | 167 | — |
| Best for | Agentic coding, Long-running agents, Enterprise knowledge work | Self-hosting, Open-licence requirements, Arena-style chat quality |
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 Kimi K3 if…
- you need self-hosting
- you need open-licence requirements
- you need arena-style chat quality
The highest-placed open-licence model on Arena, and the one most teams have not tried yet.
Caveats: Price is Artificial Analysis' blended figure, not a vendor list price; context not verified from a primary source.
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.
Questions people ask
Which is better, Claude Opus 5.5 or Kimi K3?
Claude Opus 5.5 scores higher on the Models at Work leaderboard (91 vs 60 out of 100). Kimi K3 is about 3.5× cheaper per blended million tokens ($2.31 vs $8, one figure an Artificial Analysis estimate). On Artificial Analysis' independent Intelligence Index, Claude Opus 5.5 leads 58 to 44.
When should I choose Claude Opus 5.5 over Kimi K3?
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 Kimi K3 over Claude Opus 5.5?
Choose Kimi K3 for self-hosting, open-licence requirements, arena-style chat quality. The highest-placed open-licence model on Arena, and the one most teams have not tried yet.
Which is cheaper, Claude Opus 5.5 or Kimi K3?
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). Moonshot does not publish a simple list price for Kimi K3; Artificial Analysis estimates a blended $2.31 per million tokens (three input to one output).
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.