Anthropic releases Claude Sonnet 5.5, faster everyday work at the same token price

Why this matters

If you use Sonnet for ordinary coding and document work, the sticker price did not change: $2 per million input tokens, $10 per million output tokens, and $0.20 per million cache reads. Anthropic's claim is that the same job now costs up to 30% less because the model uses fewer tokens, and that it writes output more than 30% faster than Sonnet 5.

Cyber safeguards that used to sit on the larger models now apply here. Biology safeguards are unchanged from Sonnet 5. Haiku 5.5, the cheap high-volume model, is still not out.

What we know

• ✓ Anthropic released Claude Sonnet 5.5 on 28 September 2026 as the second model in the Claude 5.5 family, and said it runs more than 30% faster than Sonnet 5 and costs up to 30% less for most work. ^[1]
• ✓ List price matches Sonnet 5: $2 per million input tokens, $10 per million output tokens, and $0.20 per million cache reads. Anthropic says the saving comes from using fewer tokens on the same task. ^[1][2]
• ✓ Anthropic reports 70.6% on Terminal-Bench 4.0, against 10.3% for Sonnet 5, and says Sonnet 5.5 is available on Claude.ai and, for developers, on the Claude Platform, Amazon Web Services, Google Cloud, and Microsoft Foundry. ^[1]
• ✓ It is the first Sonnet model to launch with cyber safeguards and fallbacks like those on Anthropic's most capable models. Biology safeguards are unchanged from Sonnet 5. Claude Haiku 5.5 is described as coming in the weeks ahead. ^[1][2]

What is unclear

• ? How the "up to 30%" cost cut shows up on a real invoice, which depends on how many tokens your own tasks used before.
• ? When Haiku 5.5 will actually ship, and at what price.