What the evidence says
- Developer
- Anthropic
- Released
- September 29, 2025
- Domains
- Language · Vision · Multimodal
- Tasks
- Language modeling/generation · Code generation · System control · Question answering · Quantitative reasoning · Mathematical reasoning · Visual question answering
- Access
- API access
- Weights
- Closed weights
Platform facts
OpenRouter's platform listing, retrieved July 22, 2026. Routed platform prices, not first-party provider prices.
- Input price
- $3.00 per 1M tokens
- Output price
- $15.00 per 1M tokens
- Context length
- 1,000,000 tokens
- Listed on OpenRouter
- September 29, 2025
Common questions
What is Claude Sonnet 4.5?
Claude Sonnet 4.5 is a Anthropic model released September 29, 2025, according to Epoch AI's reviewed catalog record. The record classifies it under language, vision, multimodal.
How does Claude Sonnet 4.5 rank on LMArena?
No board Model Gauntlet mirrors currently lists this exact model revision under a reviewed identity, so no rating is reported here.
What does Claude Sonnet 4.5 cost?
OpenRouter lists it at $3.00 per million input tokens and $15.00 per million output tokens, retrieved July 22, 2026. Those are the platform's routed prices, not first-party provider prices.