Claude Sonnet 5.5 is official with over 30% faster performance, Anthropic says it's cheaper too
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As expected, Anthropic has officially launched Claude Sonnet 5.5, and this one is a serious upgrade. The new model is designed for everyday work, coding, agents and document creation while delivering more than 30% faster output than Sonnet 5. Anthropic also says it can cost up to 30% less per task.
Claude Sonnet 5.5 makes a massive jump in coding
The biggest headline is its coding performance. Anthropic says Sonnet 5.5 scores 70.6% on Terminal-Bench 4.0, compared with just 10.3% for Sonnet 5 and 66.4% for Opus 5.5 on the same evaluation.
The model also improves on FrontierCode and CursorBench, while Anthropic says it performs close to Opus 5.5 on several knowledge-work and computer-use evaluations. One especially wild test saw Sonnet 5.5 become the first Sonnet model to beat Pokémon Red while working only from screenshots.
| Sonnet 5.5 | Sonnet 5 | Opus 5.5 | GPT-6 Sol | |
|---|---|---|---|---|
| Agentic codingTerminal-Bench 4.0 | 70.6% | 10.3% | 66.4%¹ | — |
| Agentic codingFrontierCode 1.1 (Main) | 46.2%Max² | 42.4% | 54.4% | 49.3% |
| 52.1%Xhigh | ||||
| Agentic codingCursorBench 4.0 | 55.5% | 34.1% | 57.8% | — |
| Knowledge workGDPval-AA v2.1³ | 1844 | 1449 | 1846 | 1487⁴ |
| Knowledge workAA-Briefcase v1.1³ | 1811 | 1359 | 1822 | 1483⁴ |
| Multidisciplinary reasoningHumanity’s Last Exam | 64.5%with tools | 54.9%with tools | 67.7%with tools | — |
| Computer useOSWorld 2.1 | 80.1%partial | 57.0%partial | 81.8%partial | — |
| Visual chart recognitionChartography | 61.6%no tools | 15.6%no tools | 64.4%no tools | 53.6%⁴no tools |
Sonnet 5.5 keeps the same pricing but gets cheaper to run
Anthropic has kept Sonnet 5.5 at $2 per million input tokens and $10 per million output tokens, with cache reads costing $0.20 per million tokens. However, the company says the model typically needs fewer tokens to complete the same work, resulting in costs up to 30% lower per task in its testing.
It also generates output more than 30% faster than Sonnet 5, making it Anthropic’s fastest Sonnet model yet. That efficiency could be especially useful for developers running coding agents, where fewer tool calls and shorter execution times can quickly add up. Here’s a quick look at the pricing:
| Price per 1M tokens | Claude Sonnet 5.5 | Claude Opus 5.5 |
|---|---|---|
| Cache reads | $0.20 | $0.20 |
| Cache writes | $2.50 | $5 |
| Input tokens | $2 | $4 |
| Output tokens | $10 | $20 |
Anthropic is giving Sonnet stronger safety protections
Sonnet 5.5 is also the first Sonnet model to launch with cybersecurity safeguards and fallbacks similar to those used with Anthropic’s more capable models. The company says its cyber capabilities have improved substantially over Sonnet 5.
Anthropic says Sonnet 5.5 is now available across its platforms, as well as Amazon Web Services, Google Cloud and Microsoft Azure. Developers can access it through the Claude Platform using claude-sonnet-5-5.
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