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Claude Sonnet 4.5API
Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows.
Prices update automatically — checked hourly against provider list prices.
- $6 per 1M tokens, assuming 3 input for 1 output the convention used by Artificial Analysis
- cheaper than 19% of the 173 commercial models tracked here
- 14 of 30 Anthropic models tracked here, from cheapest
Benchmarks & performance
Independent benchmark scores for Claude Sonnet 4.5, measured by Artificial Analysis. Higher is better. Measurement mode: Reasoning.
Models at this level cost $1.56 per 1M tokens (median of 22) — this one costs $6.
Cheaper and better on this index: Claude Opus 4.8 (batch) · GPT-5.6 Terra · GPT-5.5 (batch) and 54 more
About this model
Claude Sonnet 4.5 is a commercial AI model by Anthropic. The specifications below are tracked automatically: pricing is refreshed hourly from public list prices, so the numbers on this page reflect the current cost of using the model through its API.
Frequently asked questions
What is Claude Sonnet 4.5?
Claude Sonnet 4.5 is an AI language model from Anthropic. It is a proprietary model, available through an API. It scores 36.4 on the Artificial Analysis intelligence index.
Is Claude Sonnet 4.5 free?
Claude Sonnet 4.5 is not free: it costs $3 per million input tokens and $15 per million output tokens. Open-weight alternatives can be self-hosted at no per-token cost.
What is Claude Sonnet 4.5 good at?
Independent benchmarks from Artificial Analysis give it GPQA 83.4%, MMLU-Pro 87.5%, Humanity's Last Exam 17.3%, Long Context Reasoning 65.7%, LiveCodeBench 71.4%, SciCode 44.7%, AIME 2025 88%, IFBench 57.3%, τ²-Bench 78.1%, τ-Bench Banking 19%, Terminal-Bench 55.8%, Terminal-Bench Hard 35.6%. It is particularly used for code generation.