Frontier models

Claude Haiku 4.5

Claude Haiku 4.5 is Anthropic’s fastest near-frontier model for cost-sensitive work and sub-agents. The API id is claude-haiku-4-5-20251001 (alias claude-haiku-4-5). Pricing is $1 input and $5 output per million tokens.

Status: Archived
Price: $1 in, $5 outUS dollars per million tokens (word pieces) in and out, unless noted

Training

Anthropic lists a reliable knowledge cutoff of February 2025 and a training data cutoff of July 2025 (older than the Claude 5.x line). Parameter count, training FLOPs, and the full post-training recipe for this SKU are not published on the models overview or choosing guide.

Inference

Extended thinking is supported (not adaptive thinking). The effort parameter is not supported. Claude Haiku 5.5, released 7 October 2026, is now the fastest model in the Claude lineup.

Context

The documented context window is 200K tokens. Max output is 64K tokens. Inputs are text and images; output is text. The model supports multilingual use, vision, and tool use.

Methods

Extended thinking plus tools are what Anthropic names for this SKU.

Benchmarking

Anthropic has not published a Haiku 4.5 score table on the models overview or choosing guide pages cited here.

Hardware

Anthropic trains and runs Claude on AWS Trainium, Google TPUs, and NVIDIA GPUs. Amazon is the primary cloud and training partner. Anthropic reported more than 1 million Trainium2 chips in use as of April 2026. Per-SKU serving silicon is not published. Buyers purchase API tokens, not a named Claude GPU SKU.

Access and pricing

Pricing is $1 input and $5 output per million tokens.