On Wednesday, Anthropic released Claude Haiku 4.5, the newest version of its smallest model. The company bills it as offering similar performance to its Sonnet 4 model at one-third the cost and more than twice the speed. Anthropic cites a range of new benchmark results to back up these performance claims.
In the company’s testing, Haiku scored 73 percent on SWE-Bench verified and 41 percent on the command-line-focused Terminal-Bench. These scores are below those of Sonnet 4.5 but are on par with Sonnet 4, GPT-5, and Gemini 2.5 in each case. Tests also show similar results on benchmarks for tool use, computer use, and visual reasoning.
The new version of Haiku will be immediately available under all free Anthropic plans. The company believes it will be particularly appealing for free versions of AI products, where it can provide significant capabilities while minimizing server loads. The lightweight nature of the model also means it is easier to deploy multiple Haiku agents in parallel or in combination with a more sophisticated model.
In a statement to the press, Anthropic Chief Product Officer Mike Krieger said that Haiku would make new styles of deployment possible in production for the first time. He stated that it is opening up entirely new categories of what is possible with AI in production environments, with Sonnet handling complex planning while Haiku-powered sub-agents execute at speed. Krieger explained that they are giving people a complete agent toolbox where each model has the right combination of intelligence, speed, and cost for different parts of the job.
The most immediate applications are likely to come in software development tools, where Claude Code is already commonly used and latency is often a critical factor. In statements provided by Anthropic, Zencoder CEO Andrew Filev described the new version of Haiku as unlocking an entirely new set of use cases.
Haiku 4.5 comes after a string of high-profile launches for Anthropic. It arrives just two weeks after the launch of Sonnet 4.5 and two months after the launch of Opus 4.1, both of which were hailed as state-of-the-art upon release. The previous version of Haiku was released in October 2024.