Grok 4.6 versus Kimi K2.6

What are we comparing?

Grok 4.6 and Kimi K2.6 are the flagship models of two major developers, one from xAI, the other from Moonshot AI. Grok 4.6 was released on August 12, 2026, Kimi K2.6 on April 20, 2026.

All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.

Performance

On our capability index, Grok 4.6 scores 86.1 out of 100 and Kimi K2.6 84.4. Grok 4.6 leads by 1.7 points.

On the 3 benchmarks reported for both, Grok 4.6 wins 3 times and Kimi K2.6 0:

• GPQA Diamond (PhD-level science questions): Grok 4.6 94%, Kimi K2.6 90.8%
• OTIS Mock AIME (competition mathematics problems): Grok 4.6 99.2%, Kimi K2.6 96.1%
• FrontierMath (very hard research-level mathematics): Grok 4.6 66%, Kimi K2.6 57.2%

Pricing

Grok 4.6 costs $2 per million input tokens and $6 per million output tokens; Kimi K2.6 costs $0.95 and $4.

For a typical agent task (read 20,000 tokens, write 2,000), expect $0.052 with Grok 4.6 versus $0.027 with Kimi K2.6. Kimi K2.6 is 1.9 times cheaper, a gap that adds up quickly over 1,000 tasks: $25 difference.

Run the numbers with your own volumes in the agent cost calculator.

Features and limits

Grok 4.6 reads more in one go: 500,000 tokens of context (roughly 750 pages), versus 262,144 for Kimi K2.6.

Reasoning mode: Grok 4.6 yes, Kimi K2.6 yes. Tool calling: Grok 4.6 yes, Kimi K2.6 yes. Image input: Grok 4.6 yes, Kimi K2.6 yes.

Kimi K2.6 publishes its weights and can run on your servers; Grok 4.6 is a closed model, available only through an API.

Knowledge cutoff: February 1, 2026 for Grok 4.6, January 2025 for Kimi K2.6.

In short

Our reading of the data:

• Choose Grok 4.6 for a higher capability index, a larger context window and a more recent release.
• Choose Kimi K2.6 for a lower cost and open weights (you can host it yourself).

This verdict relies on public figures; it does not replace a trial on your own tasks.