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Grok 4.6 vs GPT-5.6
Of the 5 public leaderboards that rate both, Grok 4.6 scores higher on 2 and GPT-5.6 on 3. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, Grok 4.6 is at 60 and GPT-5.6 at 70.2 (out of 100).
Scores as published by each board; table composed September 25, 2026.
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Leaderboard by leaderboard
| Board | Grok 4.6 | GPT-5.6 | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,624.2 | 1,617.1 | Grok 4.6 |
| LiveBench global average (0-100) | 78 | 81.1 | GPT-5.6 |
| SimpleBench AVG@5 % (private set) | 75.9 | 71.7 | Grok 4.6 |
| Vals AI Vals Index accuracy % · weighted finance + coding tasks | 59.2 | 63.7 | GPT-5.6 |
| Artificial Analysis intelligence index · measured runs only | 44.3 | 47 | GPT-5.6 |
Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.
Grok 4.6 at a glance
- Developer
- xAI
- Status
- Live since August 12, 2026
- API price
- $2 input / $6 output per 1M tokens · xAI, grok-4.6
- Context window
- 500K tokens
Live — Aug 12 at $2/$6 per 1M, unchanged from Grok 4.5.
GPT-5.6 at a glance
- Developer
- OpenAI
- Status
- Live since July 9, 2026
- API price
- $4 input / $20 output per 1M tokens · OpenAI, gpt-5.6
- Context window
- 1.05M tokens
Live — Sol · Terra · Luna since Jul 9 · repriced Jul 30: Luna −80%, Terra −20%.
Three ChatGPT leaks in five hours were one release note — and the line none of them quoted is the real change
2026-08-06 · Three separate leaks landed in five hours claiming three separate ChatGPT changes: an upgraded GPT-5.6 Sol for Plus and Pro, a new reasoning slider rolling out, and unlimited chats coming for free users. All three are real.
OpenAI cut Luna 80% — Azure kept the old price, so Luna costs 5× more on Azure than direct
2026-08-04 · OpenAI cut GPT-5.6 Luna by 80% on July 30. We covered it. What we did not check — and should have, because it is the number that actually lands on a bill — is whether the clouds passed it on.
Grok 4.6 vs GPT-5.6: quick answers
Which is better, Grok 4.6 or GPT-5.6?
It depends on what you measure. Of the 5 public leaderboards that rate both, Grok 4.6 scores higher on 2 and GPT-5.6 on 3. Grok 4.6's widest lead is on LMArena; GPT-5.6'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, Grok 4.6 is at 60 and GPT-5.6 at 70.2 (out of 100).
Which is newer, Grok 4.6 or GPT-5.6?
Grok 4.6. It went live on August 12, 2026, 34 days after GPT-5.6 (July 9, 2026).
Which is cheaper, Grok 4.6 or GPT-5.6?
Grok 4.6 is cheaper on both input and output. On each vendor's own API, Grok 4.6 is $2 input / $6 output per million tokens and GPT-5.6 is $4 input / $20 output per million tokens. Grok 4.6's rate rises for prompts over 200K tokens; GPT-5.6's rate rises for prompts over 272K tokens. Prices as published in the models.dev catalog, as of 2026-09-25.
Which has the bigger context window, Grok 4.6 or GPT-5.6?
GPT-5.6, at 1.05M tokens against Grok 4.6's 500K, as each vendor lists it.
Who makes Grok 4.6 and GPT-5.6?
Grok 4.6 is from xAI; GPT-5.6 is from OpenAI.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed September 25, 2026). Boards measure different things, so raw scores are only comparable within a row.
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Also: the bench index · API pricing · the wire