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Claude Sonnet 4.5 vs Grok 2.5

3 vs 0 benchmarks won

Anthropic
Claude Sonnet 4.5
xAI
Grok 2.5
Overview
CompanyAnthropicxAI
Release dateSep 29 2025Aug 2025
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
83.4%
Software engineering
SWE-Bench Verified
77.2%
Multimodal understanding
MMMU
68%
Timeline
Release gapGrok 2.5 shipped 59 days before Claude Sonnet 4.5

Which is better: Claude Sonnet 4.5 or Grok 2.5?

Claude Sonnet 4.5 leads Grok 2.5 on 3 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Grok 2.5 shipped 59 days before Claude Sonnet 4.5, 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 — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

Frequently asked questions

When was Claude Sonnet 4.5 released?
Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.
When was Grok 2.5 released?
Grok 2.5 was released by xAI on Aug 2025.

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