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Kimi K3 vs Claude Opus 4.8
Of the 5 public leaderboards that rate both, Kimi K3 scores higher on 3 and Claude Opus 4.8 on 2. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Kimi K3 is at 60.4 and Claude Opus 4.8 at 47.8 (out of 100).
Scores as published by each board; table composed September 24, 2026.
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Leaderboard by leaderboard
| Board | Kimi K3 | Claude Opus 4.8 | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,659.6 | 1,555.2 | Kimi K3 |
| LiveBench global average (0-100) | 79.2 | 76.2 | Kimi K3 |
| SimpleBench AVG@5 % (private set) | 60.7 | 64.8 | Claude Opus 4.8 |
| Vals AI Vals Index accuracy % · weighted finance + coding tasks | 57.8 | 60.9 | Claude Opus 4.8 |
| Artificial Analysis intelligence index · measured runs only | 43.6 | 41.8 | Kimi K3 |
Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.
Kimi K3 at a glance
- Developer
- Moonshot
- Status
- Live since July 15, 2026
- API price
- $3 input / $15 output per 1M tokens · Moonshot AI, kimi-k3
- Context window
- 1.05M tokens
Live — dropped Jul 15 · 2.8T · open weights landed Jul 28 (1.56 TB, MXFP4).
Kimi K3, day one: impressive, expensive, and a little slow
2026-07-16 · Kimi K3 has been live for a day, and the picture forming is more interesting than the launch-night hype. Here's everything we're seeing so far.
Claude Opus 4.8 at a glance
- Developer
- Anthropic
- Status
- Live since May 27, 2026
- API price
- $5 input / $25 output per 1M tokens · Anthropic, claude-opus-4-8
- Context window
- 1M tokens
Live.
Kimi K3 vs Claude Opus 4.8: quick answers
Which is better, Kimi K3 or Claude Opus 4.8?
It depends on what you measure. Of the 5 public leaderboards that rate both, Kimi K3 scores higher on 3 and Claude Opus 4.8 on 2. Kimi K3's widest lead is on LMArena; Claude Opus 4.8'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 is at 60.4 and Claude Opus 4.8 at 47.8 (out of 100).
Which is newer, Kimi K3 or Claude Opus 4.8?
Kimi K3. It went live on July 15, 2026, 49 days after Claude Opus 4.8 (May 27, 2026).
Which is cheaper, Kimi K3 or Claude Opus 4.8?
Kimi K3 is cheaper on both input and output. On each vendor's own API, Kimi K3 is $3 input / $15 output per million tokens and Claude Opus 4.8 is $5 input / $25 output per million tokens. Prices as published in the models.dev catalog, as of 2026-09-24.
Which has the bigger context window, Kimi K3 or Claude Opus 4.8?
Kimi K3, at 1.05M tokens against Claude Opus 4.8's 1M, as each vendor lists it.
Who makes Kimi K3 and Claude Opus 4.8?
Kimi K3 is from Moonshot; Claude Opus 4.8 is from Anthropic.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed September 24, 2026). Boards measure different things, so raw scores are only comparable within a row.
More comparisons
Watch free: Chrome push the moment a new model answers on a public API, an email about 15 minutes later. Also: the bench index · API pricing · the wire