Model comparison
Claude Opus 5.5 vs Claude Sonnet 5 (Free)
Compare published model capabilities and API prices.
Anthropic
Claude Opus 5.5
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step chan
Anthropic
Claude Sonnet 5 (Free)
Everyday Claude agent model for coding, planning, browsing, and general work
| Metric | Claude Opus 5.5 | Claude Sonnet 5 (Free) |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Context window | 1,000,000 | 1,000,000 |
| Input $/Mtok | $4.00 | $0 |
| Output $/Mtok | $20.00 | $0 |
| Modalities | text, vision | text, vision |
| License | unknown | closed |
Quick take
On input price, Claude Sonnet 5 (Free) is cheaper at $0/Mtok. For context window, Claude Opus 5.5 leads with 1,000,000 tokens.
Pick based on your workload: high-volume cheap inference vs long-document / agent loops. Enterprise DNA can wire either model into Omni with evals, secrets, and job orchestration.