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Kimi K3.1 Pro vs Claude Opus 5.5
Claude Opus 5.5 scores higher than Kimi K3.1 Pro on all 3 public leaderboards that rate both. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Kimi K3.1 Pro is at 86 and Claude Opus 5.5 at 100 (out of 100).
Scores as published by each board; table composed October 25, 2026.
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Leaderboard by leaderboard
| Board | Kimi K3.1 Pro | Claude Opus 5.5 | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,691.6 | 1,806.9 | Claude Opus 5.5 |
| Vals AI Vals Index accuracy % · weighted finance + coding tasks | 62.5 | 70.2 | Claude Opus 5.5 |
| Artificial Analysis intelligence index · measured runs only | 55.1 | 57.6 | Claude Opus 5.5 |
Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.
Kimi K3.1 Pro at a glance
- Developer
- Moonshot
- Status
- Live since October 23, 2026
- API price
- $2 input / $10 output per 1M tokens · Moonshot AI, kimi-k3.1-pro
- Context window
- 1.05M tokens
Live — Oct 23 (Kimi app ~16:00 UTC, API 17:15 UTC per Moonshot) · kimi-k3.1-pro $2/$10 per 1M, cached input $0.20; kimi-k3.1-pro-highspeed (2-3× faster) $4/$20; K3 was $3/$15 · 1M ctx · 2.8T total / 104B active MoE, multimodal, a post-trained K3 · open weights promised by Nov 4 · first model in Moonshot's K3.1 series · Moonshot's own table: Terminal-Bench 4.0 65.7% vs Opus 5.5 66.4% and GPT-6 Astra 58.2% · hunted since Jul 30 (researcher-confirmed for August; internal name k3d1-agent).
Kimi K3.1 Pro is live: $2 / $10 on the Kimi API, a 1M-token context, open weights by Nov 4
2026-10-23 · Moonshot launched Kimi K3.1 Pro today. It is on the Kimi API now at $2 per million input tokens and $10 per million output, a faster Highspeed version costs $4 and $20, and Moonshot says the full weights will be released by Nov 4.
Moonshot teases Kimi K3.1: its own video shows Kimi Code running the model
2026-10-23 · Moonshot AI posted a 24-second teaser video on X on October 23 whose first shot is its coding agent, Kimi Code, with the model line reading "Kimi K3.1". The video ends on the Kimi wordmark and gives no date, price or benchmark.
Claude Opus 5.5 at a glance
- Developer
- Anthropic
- Status
- Live since September 22, 2026
- API price
- $4 input / $20 output per 1M tokens · Anthropic, claude-opus-5-5
- Context window
- 1M tokens
Live — Sep 22 · $4/$20 per MTok, down from Opus 5 at $5/$25 · 1M ctx / 128K out · adaptive thinking always on, default effort medium · cache reads 5% of base input · Anthropic now says start here for most workloads, and Opus 5 is legacy · fast mode (speed: 'fast', up to 2.5x the output tokens per second by Anthropic's figure) at $8 / $40 per MTok, double standard, left research preview Oct 15 with no waitlist, access request or beta header; on the Claude API and on Claude in Microsoft Foundry (Azure-hosted), not on Bedrock, Google Cloud, Claude Platform on AWS, the Batch API or Priority Tier; @ClaudeDevs says Google Cloud is coming soon (Anthropic's fast mode docs, read Oct 16).
Anthropic opens a research preview of Claude Duet, a proactive agent app built around Opus 5.5
2026-10-22 · Anthropic opened a research preview of Claude Duet on October 21, a new app in which Claude works as a proactive agent: it brings you what needs your attention, completes tasks you hand it, keeps working when you step away, and checks with you before it acts on your behalf.
Claude Opus 5.5 fast mode leaves research preview: no waitlist, $8 / $40, now on Microsoft Foundry too
2026-10-16 · Anthropic took fast mode for Claude Opus 5.5 out of research preview on October 15 and removed the waitlist. Any Claude API user can now set speed: "fast" on an Opus 5.5 request with no access request and no beta header; requests that still send the old header keep working.
Kimi K3.1 Pro vs Claude Opus 5.5: quick answers
Which is better, Kimi K3.1 Pro or Claude Opus 5.5?
It depends on what you measure. Claude Opus 5.5 scores higher than Kimi K3.1 Pro on all 3 public leaderboards that rate both. Claude Opus 5.5's widest lead is on Vals AI. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Kimi K3.1 Pro is at 86 and Claude Opus 5.5 at 100 (out of 100).
Which is newer, Kimi K3.1 Pro or Claude Opus 5.5?
Kimi K3.1 Pro. It went live on October 23, 2026, 31 days after Claude Opus 5.5 (September 22, 2026).
Which is cheaper, Kimi K3.1 Pro or Claude Opus 5.5?
Kimi K3.1 Pro is cheaper on both input and output. On each vendor's own API, Kimi K3.1 Pro is $2 input / $10 output per million tokens and Claude Opus 5.5 is $4 input / $20 output per million tokens. Prices as published in the models.dev catalog, as of 2026-10-24.
Which has the bigger context window, Kimi K3.1 Pro or Claude Opus 5.5?
Kimi K3.1 Pro, at 1.05M tokens against Claude Opus 5.5's 1M, as each vendor lists it.
Who makes Kimi K3.1 Pro and Claude Opus 5.5?
Kimi K3.1 Pro is from Moonshot; Claude Opus 5.5 is from Anthropic.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed October 25, 2026). Boards measure different things, so raw scores are only comparable within a row.
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