Claude Sonnet 4vsGrok 4 Fast
Claude Sonnet 4 | Grok 4 Fast | |
|---|---|---|
| API pricingUSD per 1M tokens · lower wins | ||
Cheapest inputLowest input rate across third-party providers, excluding the lab itself. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page. | $3.00Amazon Bedrock | — |
Cheapest outputLowest output rate across third-party providers, excluding the lab itself. May come from a different provider than the cheapest input. | $15.00Amazon Bedrock | — |
| BenchmarksPublished by one model only | ||
BullshitBench v2Nonsense detection — Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 30% | — |
SWE-Bench VerifiedCoding — Real coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 72.7% | — |
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 75.4% | — |
| Overview | ||
| Company | Anthropic | SpaceXAI |
| Release date | May 22 2025 | Sep 19 2025 |
| Access | Proprietary | Proprietary |
Other comparisons
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Frequently asked questions
Claude Sonnet 4 and Grok 4 Fast don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude Sonnet 4 shipped 120 days before Grok 4 Fast, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
Direct benchmark comparisons are unavailable — Claude Sonnet 4 and Grok 4 Fast don't publish scores on any of the same benchmarks.