Anthropic: Claude Sonnet 4.5
Analysis Summary
Claude Sonnet 4.5 is Anthropic's Sonnet model, with vision, tool use, function calling, and a one-million-token context window. Its measured coding and agentic results are both strong, supported by useful math, knowledge, and long-context performance. Instruction following is also measured, giving teams evidence to assess its fit for controlled business workflows.
It is a strong candidate for software engineering, tool-using agents, and analysis of long documents or codebases. Vision extends its use to image-based work, while the agentic profile supports multi-step tasks more convincingly than the weaker models in this batch. Human review remains appropriate for consequential outputs, particularly when agents can invoke tools or produce client-facing content.
The listed output price is premium, so routine high-volume requests may be better routed to a cheaper model. Adopt Sonnet 4.5 for demanding work where coding quality, context, and tool execution justify the cost.
Assessed September 23, 2026
Editorial notes
Claude Sonnet 4.5 pairs strong coding and agentic results with vision, tool and function calling, and a one-million-token context; its premium output price suits high-value work.
The DFO score ranks models on the Artificial Analysis Intelligence Index and is refreshed as new models launch. The write-up and verdict are our own. Feedback?
DFO Verdict
Claude Sonnet 4.5 pairs strong coding and agentic results with vision, tool and function calling, and a one-million-token context; its premium output price suits high-value work.
Benchmarks
Artificial Analysis data refreshed Oct 18, 2026. Arena ratings from the Oct 13, 2026 text leaderboard, with style control. Bars: magenta = reasoning, ink = coding and agents, cyan = instructions and long context.
Artificial Analysis no longer lists this model, so its indexes are converted from their older scale to stay comparable.
How Anthropic: Claude Sonnet 4.5 compares
Anthropic: Claude Sonnet 4.5 ranks #56 of 439 AI models we track for overall intelligence, #79 of 198 for coding, #17 of 181 for agentic tasks. Its 1M-token context window is larger than 85% of the models we list. At $3.00 per million input tokens it is cheaper than 9% of comparable models.
Dark bar = input · light bar = output, scaled to the priciest peer.
1M tokens ≈ 8 full-length novels or ~2,500 pages of business documents in a single request.
Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $3.00 | $0.003000 |
| Output | $15.00 | $0.015000 |
What would Anthropic: Claude Sonnet 4.5 cost your business?
Pick the job that looks most like yours, then fine-tune with the sliders. Estimates update live.
A website chatbot handling around 100 customer conversations a day, a few short messages each.
Full calculator with 713 models → Price Calculator
These numbers get smaller with the right architecture.
We route routine calls to cheap models and save Anthropic: Claude Sonnet 4.5 for the hard ones. Most clients cut their estimate by 60-80%.
Talk to our teamAbout Anthropic: Claude Sonnet 4.5
Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with..
Frequently asked questions about Anthropic: Claude Sonnet 4.5
How much does Anthropic: Claude Sonnet 4.5 cost?
Anthropic: Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens.
What is the context window of Anthropic: Claude Sonnet 4.5?
Anthropic: Claude Sonnet 4.5 has a context window of 1,000,000 tokens (1M).
Is Anthropic: Claude Sonnet 4.5 good for coding?
On our coding benchmark index, Anthropic: Claude Sonnet 4.5 ranks #79 of 198 models, placing it in the broader range of the field for code generation and debugging.
What can Anthropic: Claude Sonnet 4.5 do?
Anthropic: Claude Sonnet 4.5 supports image/vision input, tool use, and function calling.
Who created Anthropic: Claude Sonnet 4.5?
Anthropic: Claude Sonnet 4.5 is developed by Anthropic and was released on September 29, 2025.