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Anthropic releases Claude Sonnet 5.5, which it says is faster than Sonnet 5

2026-09-30 · that day's edition

Anthropic says Sonnet 5.5 generates outputs 30 percent or more faster than Sonnet 5, at $2 per million input tokens and $10 per million output tokens.

The API name is claude-sonnet-5-5. Anthropic says Sonnet 5.5 generates outputs 30 percent or more faster than Sonnet 5 and, in its own testing, costs up to 30 percent less per task. It reports 70.6 percent on Terminal-Bench 4.0, against 10.3 percent for Sonnet 5. These are figures from Anthropic itself.

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  1. Claude Sonnet 5.5 costs $2 per million input tokens and $10 per million output tokens. Quote: "$2 per million input tokens, $10 per million output tokens"

    Claude Sonnet 5.5 · Anthropic · 2026-09-28
    Sonnet 5.5 is priced the same as Sonnet 5 at $2 per million input tokens, $10 per million output tokens, and $0.20 per million tokens for cache reads

  2. The API model name is claude-sonnet-5-5. Quote: "claude-sonnet-5-5"

    Claude Sonnet 5.5 · Anthropic · 2026-09-28
    Developers can get started on the Claude Platform with claude-sonnet-5-5.

  3. Anthropic says Sonnet 5.5 is available on all platforms, including Amazon Web Services, Google Cloud and Microsoft Azure. Quote: "Claude Sonnet 5.5 is now available on all platforms, including Amazon Web Services, Google Cloud, and Microsoft Azure."

    Claude Sonnet 5.5 · Anthropic · 2026-09-28
    Claude Sonnet 5.5 is now available on all platforms, including Amazon Web Services, Google Cloud, and Microsoft Azure.

  4. Anthropic says that in its own testing Sonnet 5.5 costs up to 30 percent less per task than its predecessor.

    narrowed to what the source supports
    Claude Sonnet 5.5 · Anthropic · 2026-09-28
    In our testing, it costs up to 30% less per task than its predecessor.

  5. Anthropic reports Sonnet 5.5 scores 70.6 percent on Terminal-Bench 4.0, against 10.3 percent for Sonnet 5. Quote: "Sonnet 5.5 scores 70.6% on Terminal-Bench 4.0, an agentic coding evaluation, compared to Sonnet 5"

    Claude Sonnet 5.5 · Anthropic · 2026-09-28
    Sonnet 5.5 scores 70.6% on Terminal-Bench 4.0, an agentic coding evaluation, compared to Sonnet 5’s 10.3%.

  6. Anthropic says Sonnet 5.5 generates outputs 30%+ faster than Sonnet 5. Quote: "Sonnet 5.5 generates outputs 30%+ faster than Sonnet 5, making it our fastest Sonnet model to date."

    Claude Sonnet 5.5 · Anthropic · 2026-09-28
    Sonnet 5.5 generates outputs 30%+ faster than Sonnet 5, making it our fastest Sonnet model to date.

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