Anthropic: Sonnet 5.5 is faster, and still at Claude
On 28 September 2026, Anthropic announces Claude Sonnet 5.5. At least 30 percent faster than Sonnet 5, up to 30 percent cheaper for most work, at the same listed price: 2 dollars per million input tokens, 10 output. The model is not at your place.
Getting started
Original AI-generated illustration · SecuFocus
At a glance
Key points
Sonnet 5.5 is presented as the everyday complement to Opus 5.5, not as the model for hard judgment. The scores, including 70.6 percent on Terminal-Bench 4.0 against 10.3 percent for Sonnet 5, are Anthropic’s. A question sent to Claude leaves for Anthropic.
What changes
The page is dated 28 September 2026. Sonnet 5.5 is the second model in the 5.5 family. Anthropic aims it at bounded tasks, bugs, documents, slides and spreadsheets. Haiku 5.5, for high volume, is announced for the following weeks, not for that day.
The listed price stays Sonnet 5’s: 2 dollars per million input tokens, 10 output, 0.20 for a cache read. The cost cut, according to the page, comes from fewer tokens for the same work, and from speed. It is not a cut in the unit price.
What leaves
Nothing in the announcement describes a weight to download. Sonnet 5.5 is reached like the other hosted Claude models. The document, the code or the screenshot you give it leaves the machine.
“First Sonnet to beat Pokémon Red from screenshots” is a capability sentence, not an invitation to give it your screen. If a tool already sends it pictures of your desktop, that channel existed before the 5.5 name.
What we did not verify
We did not call the model, measure the 30 percent, or rerun Terminal-Bench. The price is the one written on the page.
The decision
If you pay for Sonnet by the token, reread the bill after a few days: the unit price did not drop, the volume may have. If you wanted a local model, this announcement does not give you one.
Check and explore
Sources for this article
Numbers connect each reference to the passages that use it. Dates show when the documentation was consulted.
- Claude Sonnet 5.5, Anthropic ↗anthropic.com ·
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