Claude Sonnet 4.5

Published

Sep 29, 2025

Claude Sonnet 4.5 is an AI model developed by Anthropic (United States), first published in September 2025. It works in the language, vision and multimodal domain, on tasks such as language modeling/generation, code generation, system control and 4 more.

Epoch AI has no training-compute estimate for this model.

Access: API access. Its weights are not openly released.

Full record

Organization: Anthropic
Country of organization: United States
Domain: Language, Vision, Multimodal
Task: Language modeling/generation, Code generation, System control, Question answering, Quantitative reasoning, Mathematical reasoning, Visual question answering
Model accessibility: API access
Open weights: No

Benchmark results

01

Epoch Capabilities Index

ECI Score

146.8