Anthropic launches Claude Sonnet 5.5: same $2/$10 price, 30% faster and cheaper per task
Anthropic shipped Claude Sonnet 5.5 on September 28, 2026 — the second model in its Claude 5.5 family — priced the same as Sonnet 5 but 30% faster at generating outputs and up to 30% cheaper per completed task, one day before OpenAI answered with GPT-6.1 Sol at the identical $2/$10 price.
What happened
Anthropic on Monday released Claude Sonnet 5.5, the second model in its Claude 5.5 family, as the AI lab expands its product lineup ahead of a planned IPO, according to Reuters. It follows last week's Claude Opus 5.5 launch and lands just one day before OpenAI's DevDay 2026, where OpenAI released GPT-6.1 Sol at the exact same $2/$10 per-million-token price.
Pricing and availability
Claude Sonnet 5.5 is priced the same as Sonnet 5: $2 per million input tokens, $10 per million output tokens, $0.20 per million tokens for cache reads, and $2.5 per million tokens for cache writes, per Gadgets360. It is available via the Claude Platform and all major cloud platforms — Amazon Web Services, Google Cloud, and Microsoft Azure. Anthropic says the model needs fewer tokens to complete the same work, making it up to 30% cheaper per task, and calls it the company's fastest model yet with outputs generated 30% faster than Sonnet 5.
Benchmarks
On Terminal-Bench 4.0's Agentic Coding test, Sonnet 5.5 scored 70.6%, outperforming both Sonnet 5 (10.3%) and Opus 5.5 (66.4%). On FrontierCode 1.1 it scored 46.2%, bringing it closer to Opus 5.5 (54.4%) and OpenAI's GPT-6 Sol (49.3%), per Gadgets360. Anthropic also says Sonnet 5.5 improved on or matched Sonnet 5 on most measures of alignment, resistance to misuse, and honesty in its automated behavioral audit, and it is being deployed with the same safeguards as Opus 5.5.
Why it matters
Two labs, one week, the identical $2/$10 pitch: near-flagship performance without flagship prices. Anthropic positions Sonnet 5.5 as a faster, lower-cost complement to Opus 5.5 for everyday enterprise work — coding, document creation, spreadsheet work — with enterprise customers accounting for about 80% of Anthropic's business (clients include Salesforce, Databricks, Goldman Sachs, and Novo Nordisk). Reuters also reports a third model, Haiku 5.5, designed for fast, high-volume work, is due soon.
Sources:
- https://www.reuters.com/technology/anthropic-rolls-out-second-claude-55-model-it-builds-toward-ipo-2026-09-28/
- https://www.gadgets360.com/ai/news/anthropic-claude-sonnet-5-5-ai-model-launch-performance-cost-availability-12113998
Verified September 30, 2026