Claude Sonnet 4.5 — pricing, context window and what it's actually good for

Claude Sonnet 4.5 is an Active Claude model on the Claude API. 200k-token context, 64k max output. Training data cutoff July 2025. Uses the tokenizer used by Claude Sonnet 4.6 and earlier, so per-token costs are directly comparable with models of that generation. Tentative retirement date: not sooner than 29 September 2026 (Anthropic model deprecations, checked 2026-08-07 11:51 UTC).

Context window: 200,000 tokens
Max output: 64,000 tokens
Released: 29 Sep 2025
Knowledge cutoff: Jan 2025
API identifier: claude-sonnet-4-5-20250929

Pricing · per 1M tokens

Input$3.00

Output$15.00

Cached input$0.30

Cached input is 10× cheaper on this model — it pays off when you send the same context again and again.

Checked against Anthropic pricing docs on 7 Aug 2026, 11:51 UTC

Best for

Content Writing Code Generation Customer Support Agents

Sources: Anthropic pricing docs · Anthropic models overview · Anthropic model deprecations

Not sure Claude Sonnet 4.5 fits your workload?

We'll size the right model for your use case and give you a real cost estimate. One free call, no slides.

Talk to us