Claude Sonnet 5

Claude Sonnet 5 is the mid-tier model in Anthropic's Claude family of AI models. It costs far less than Anthropic's top-tier model, Fable 5, yet is widely seen as good enough for most real-world work with little practical difference.

Think of it in car terms: Fable 5 is the luxury sedan, while Sonnet 5 is the reliable compact car that handles almost any road just fine. This distinction matters most in use cases involving heavy back-and-forth text exchange, like multi-step automated workflows, where the cost of processing text (measured in tokens) translates directly into operating expenses—making price as important as raw performance.

In August 2026, when Anthropic first launched Sonnet 5, it introduced a discounted rate of $2 per million input tokens and $10 per million output tokens. The company later announced it would keep that launch pricing in place indefinitely, rather than raising it as originally planned.

The article notes that "on August 10, Anthropic announced it would keep the launch pricing for its mid-tier model, Claude Sonnet 5, in place indefinitely." A common misconception here is assuming Sonnet 5 is Anthropic's top-performing model—in reality, it sits one tier below the flagship Fable 5. It's precisely this low price that has made Sonnet 5 the preferred choice for token-heavy workloads.