Claude Sonnet 5.5

Anthropic · released 28 Sept 2026

Input$2per 1M tokens

Output$10per 1M tokens

Context1,000Ktokens

WeightsClosed

context on a 1K–2M scale

About

Claude Sonnet 5.5 is Anthropic’s Sonnet-class model for everyday work with well-scoped tasks. It accepts text, images and files, and generates text. The listed summary highlights feature building and bug fixing as areas of strength, and describes it as a direct upgrade to Claude Sonnet 5. It has a 1,000,000-token context window, supports reasoning and tools, and allows up to 128,000 output tokens. The model ID is anthropic/claude-sonnet-5.5. Input pricing is USD 2 per 1M tokens, while output pricing is USD 10 per 1M tokens. Its listed release date is 2026-09-28. For teams assessing the model, the main points are its broad context capacity, image and file inputs, tool support, and the difference between input and output rates.

Who it is for

Claude Sonnet 5.5 suits product and engineering teams working on bounded tasks such as building features or fixing bugs. It is also relevant when workflows need image or file inputs, tool support, or a large context window.

What is good

1,000,000-token context window
Accepts text, image and file inputs
Supports reasoning and tools
Maximum output is 128,000 tokens

What to know first

Generates text only
Output costs USD 10 per 1M tokens

Verdict

Claude Sonnet 5.5 brings a large context window and support for text, image and file inputs to everyday, well-scoped work. Its output rate is higher than its input rate, so account for both when assessing usage.

Details

Lab: Anthropicopenrouter.ai · 3 Oct 2026
Context: 1,000Kopenrouter.ai · 3 Oct 2026
Input price: $2 / 1Mopenrouter.ai · 3 Oct 2026
Output price: $10 / 1Mopenrouter.ai · 3 Oct 2026
Max output: 128,000 tokensopenrouter.ai · 3 Oct 2026
Inputs: text, image, fileopenrouter.ai · 3 Oct 2026
Open weights: Noopenrouter.ai · 3 Oct 2026

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Sources

openrouter.ai/anthropic/claude-sonnet-5.5· checked 3 Oct 2026