SI Model · Anthropic
Claude Sonnet 5.5
| Developer | Anthropic |
|---|---|
| Released | September 28, 2026 |
| Status | Current |
| Inputs | Text, Images |
| Context window | 1M tokens |
| API price (input) | $2 / 1M tokens |
| API price (output) | $10 / 1M tokens |
| Open weights | No |
| Access | Claude apps, Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry |
Specs and list prices last verified October 7, 2026. Prices change often; check the provider before you buy.
Strengths
- Fast responses with strong reasoning
- 1M-token context and 128K output
- Same list price as GPT-6.1 Sol
Best for
- Customer-facing assistants that need speed
- High-volume coding and data tasks
- Agents where latency matters
Claude Sonnet 5.5 is Anthropic’s workhorse model. Released on September 28, 2026, it is described by Anthropic as “the best combination of speed and intelligence”, fast enough for real-time products and capable enough for serious coding and analysis.
Key specs
- Context window: 1 million tokens; up to 128,000 output tokens
- Thinking: adaptive, with “high” default effort
- Price: $2 input / $10 output per million tokens; prompt-cache reads at 10% of input price; 50% off for batch
- Knowledge cutoff: June 2026
Competitors
| Model | Price (in / out per 1M) | Context |
|---|---|---|
| Claude Sonnet 5.5 | $2 / $10 | 1M |
| GPT-6.1 Sol | $2 / $10 | ~1.05M |
| Gemini 3.8 Flash | $0.75 / $3.75 (intro) | ~1M |
| Grok 4.7 | $2 / $6 (under 200K) | 500K |
See GPT-6.1 Sol vs Claude Sonnet 5.5 and Claude Sonnet 5.5 vs Gemini 3.8 Flash.
Sources
- Claude models overview — Anthropic
Written by
Luka Kušec · Editor
Editor of SI.info. Writes about Super Intelligence, technology policy and the people building frontier models.