What is Claude Sonnet 5.5?

Claude Sonnet 5.5 is a large language model from Anthropic, released on September 28, 2026. It accepts text and image input.

When was Claude Sonnet 5.5 released?

Anthropic released Claude Sonnet 5.5 on September 28, 2026.

How much does Claude Sonnet 5.5 cost?

Claude Sonnet 5.5 costs $2 per 1M input tokens and $10 per 1M output tokens through the Anthropic API. Cached input costs $0.20 per 1M tokens. Prices are from Anthropic's official pricing as of September 28, 2026.

What is Claude Sonnet 5.5's context window?

Claude Sonnet 5.5 has a 1M-token context window and can generate up to 128K output tokens.

How does Claude Sonnet 5.5 score on benchmarks?

Claude Sonnet 5.5 has 6 cited benchmark scores, including Chartography (no tools) 61.6%, CursorBench 4.0 55.5% and FrontierCode v1.1 (Main) 46.2%. Each score links to its source.

Claude Sonnet 5.5

Anthropic·Operational·Released 2026-09-28textvision

Context1,000k

Max output128k

Input / 1M$2 ↗

Output / 1M$10 ↗

Cached in$0.2

Benchmarks6

Benchmarks

Cited public sources · rank is exact-benchmark, apples-to-apples

Chartography (no tools)

61.6% ↗

CursorBench 4.0

#2/355.5% ↗

FrontierCode v1.1 (Main)

#2/246.2% ↗

Humanity's Last Exam (with tools)

#2/1564.5% ↗

OSWorld 2.1 (partial)

80.1% ↗

Terminal-Bench 4.0

#1/570.6% ↗

Compare

vs Gemini 4 Argon vs GPT-6.1 Sol vs Muse Spark 1.3 vs GPT-6 Sol vs GPT-6 Luna vs Claude Opus 5.5 vs GPT-6 Astra vs GPT-5.6 Sol

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Claude Sonnet 5.5 FAQ

What is Claude Sonnet 5.5?: Claude Sonnet 5.5 is a large language model from Anthropic, released on September 28, 2026. It accepts text and image input.
When was Claude Sonnet 5.5 released?: Anthropic released Claude Sonnet 5.5 on September 28, 2026.
How much does Claude Sonnet 5.5 cost?: Claude Sonnet 5.5 costs $2 per 1M input tokens and $10 per 1M output tokens through the Anthropic API. Cached input costs $0.20 per 1M tokens. Prices are from Anthropic's official pricing as of September 28, 2026.
What is Claude Sonnet 5.5's context window?: Claude Sonnet 5.5 has a 1M-token context window and can generate up to 128K output tokens.
How does Claude Sonnet 5.5 score on benchmarks?: Claude Sonnet 5.5 has 6 cited benchmark scores, including Chartography (no tools) 61.6%, CursorBench 4.0 55.5% and FrontierCode v1.1 (Main) 46.2%. Each score links to its source.

Access Claude Sonnet 5.5 and every other model through one endpoint with automatic failover: Respan gateway.