Claude Haiku 4.5

Claude Haiku 4.5

Proprietary Anthropic · 2025-10-15 · Proprietary

Small-tier 4.5 model released October 15 2025 at $1 / $5 per million tokens, one-third the Sonnet 4 price. Anthropic positioned it as matching Sonnet 4 on coding and computer use while running 4-5x faster than Sonnet 4.5. First Haiku to include extended thinking, computer use, and explicit context awareness.

Cost

$1.00 / Mtok input

$5.00 / Mtok output

Anthropic API · as of 2026-05-21

source ↗

Architecture

Schema-generated from data/models.yaml. Every label is auditable against the model's sources.

Specs

Architecture: unknown
Total params: not disclosed
Active params: not disclosed
Context window: 200K tokens
Attention: unknown
Position encoding: unknown
Post-training: rlhf, constitutional
OSI-approved: no
Data released: no
Training code: not released

Benchmarks

Each score carries the date it was published; we never infer or interpolate missing scores.

Code

SWE-Bench Verified

73.3

as of 2025-10-15

source ↗

Available quantizations

None. The weights are not distributed, so there are no public quantizations.

Notable innovations

· First Haiku with extended thinking
· First Haiku with computer use
· Explicit context-window awareness

Lineage

First Haiku-tier model in the 4.5 generation.

Derived from

Claude 3.5 Haiku 2024-11-04