Claude Sonnet 5.5
claude-sonnet-5-5
Anthropic · reasoning · api
Intelligence
Context
1M
Max output
128K
Input $/1M
$2.00
Output $/1M
$10.00
Modalities
text · image · document
Released
28 Sept 2026
Intelligence Index via Artificial Analysis · 0–100, higher is better
AI summary
● machine-written
Claude Sonnet 5.5: Fast reasoning model with 1M context window
Claude Sonnet 5.5 is Anthropic's mid-tier reasoning model designed for speed and intelligence balance. It supports text, image, and document inputs with a 1M token context window and 128K token maximum output. The model is available via API with adaptive thinking capabilities.
What's new
- Pricing: $2 per million input tokens, $10 per million output tokens
- 1M token context window with 128K max output tokens
- Supports text, image, and document modalities
- Adaptive thinking mode (default effort, medium level)
- Retirement guaranteed not sooner than September 28, 2027
Best for
General-purpose tasks requiring balance of speed and reasoningApplications processing images and documents alongside textLong-context document analysis and reasoning
Common questions about Claude Sonnet →
Source: https://docs.claude.com/en/docs/about-claude/models/overview