Claude Sonnet 5.5 versus Grok 4.6
Claude Sonnet 5.5 (Anthropic) and Grok 4.6 (xAI) compared point by point: measured performance, pricing, context and capabilities.
Data as of October 22, 2026
Side-by-side comparison
| Criterion | Claude Sonnet 5.5 | Grok 4.6 |
|---|---|---|
| Developer | Anthropic | xAI |
| Released | September 28, 2026 | August 12, 2026 |
| Capability index | 95.9 / 100 | 86.1 / 100 |
| Input price | $2 | $2 |
| Output price | $10 | $6 |
| Cost of a typical task | $0.06 | $0.052 |
| Context window | 1,000,000 tokens | 500,000 tokens |
| Maximum output | 128,000 tokens | 500,000 tokens |
| Reasoning mode | Yes | Yes |
| Tool calling | Yes | Yes |
| Accepted inputs | text, image, PDF | text, image, PDF |
| Open weights | No | No |
| Knowledge cutoff | June 2026 | February 1, 2026 |
The match-up at a glance
This comparison pits the flagship models of two major developers against each other: Claude Sonnet 5.5 and Grok 4.6, one from Anthropic, the other from xAI. The first dates from September 28, 2026, the second from August 12, 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, Claude Sonnet 5.5 scores 95.9 out of 100 and Grok 4.6 86.1. Claude Sonnet 5.5 leads by 9.8 points.
On the 5 benchmarks reported for both, Claude Sonnet 5.5 wins 5 times and Grok 4.6 0:
- GPQA Diamond (PhD-level science questions): Claude Sonnet 5.5 95.6%, Grok 4.6 94%
- OTIS Mock AIME (competition mathematics problems): Claude Sonnet 5.5 100%, Grok 4.6 99.2%
- FrontierMath (very hard research-level mathematics): Claude Sonnet 5.5 88.8%, Grok 4.6 66%
- FrontierCode (advanced programming tasks): Claude Sonnet 5.5 52.1%, Grok 4.6 48%
- APEX-Agents (professional tasks carried out by an agent): Claude Sonnet 5.5 75.5%, Grok 4.6 65.3%
Pricing
Claude Sonnet 5.5 costs $2 per million input tokens and $10 per million output tokens; Grok 4.6 costs $2 and $6.
For a typical agent task (read 20,000 tokens, write 2,000), expect $0.06 with Claude Sonnet 5.5 versus $0.052 with Grok 4.6. Grok 4.6 is 1.2 times cheaper, a gap that adds up quickly over 1,000 tasks: $8 difference.
Run the numbers with your own volumes in the agent cost calculator.
Features and limits
Claude Sonnet 5.5 reads more in one go: 1,000,000 tokens of context (roughly 1,500 pages), versus 500,000 for Grok 4.6.
Reasoning mode: Claude Sonnet 5.5 yes, Grok 4.6 yes. Tool calling: Claude Sonnet 5.5 yes, Grok 4.6 yes. Image input: Claude Sonnet 5.5 yes, Grok 4.6 yes.
Neither publishes its weights: both are used through an API.
Knowledge cutoff: June 2026 for Claude Sonnet 5.5, February 1, 2026 for Grok 4.6.
In short
Our reading of the data:
- Choose Claude Sonnet 5.5 for a higher capability index and a larger context window.
- Choose Grok 4.6 for a lower cost.
This verdict relies on public figures; it does not replace a trial on your own tasks.
Other comparisons
Frequently asked questions
Claude Sonnet 5.5 or Grok 4.6: which is better?
On our index (Epoch AI data), Claude Sonnet 5.5 scores 95.9 and Grok 4.6 86.1 out of 100. The best choice also depends on price and on your use case.
Which one is cheaper?
Grok 4.6. To read 20,000 tokens and write 2,000, expect $0.06 with Claude Sonnet 5.5 and $0.052 with Grok 4.6 (prices as of October 22, 2026).
Which one has the larger context window?
Claude Sonnet 5.5, with 1,000,000 tokens versus 500,000.
Can I run Claude Sonnet 5.5 or Grok 4.6 on my own servers?
No: both are closed models, available through an API.
Data sources
- Models.dev — Model data: models.dev (open-source project)
- OpenRouter — Market prices cross-checked with OpenRouter
- Epoch AI — AI Benchmarking Hub — Epoch AI, “AI Benchmarking Hub”, epoch.ai, CC BY 4.0
Data as of October 22, 2026
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