Head-to-head · Anthropic vs Anthropic
Claude Opus 5.5 vs Claude Sonnet 5
Quick answer: Claude Opus 5.5 stands out for matches Claude Fable 5.1 on most work at a much lower price. Claude Sonnet 5 stands out for lower price than Sonnet 4.6 with newer capabilities. Reviewed September 2026.
Overview
Claude Opus 5.5: Claude Opus 5.5, released on 22 September 2026, is Anthropic's newest Opus model. Anthropic reports it performs at the level of Claude Fable 5.1 on most work while costing about 40% less to run than Opus 5, with a focus on agentic coding, computer use and knowledge work.
Claude Sonnet 5: Claude Sonnet 5 is the mid-tier model in the Claude 5 family and the default choice for most professional work. Anthropic made its launch pricing of $2 and $10 per million tokens permanent, which makes it one of the best price-to-quality options in the lineup.
At a glance
| Dimension | Claude Opus 5.5 | Claude Sonnet 5 |
|---|---|---|
| Vendor | Anthropic | Anthropic |
| Starting price | API: $4 in / $20 out per M tokens | API: $2 in / $10 out per M tokens |
| Pricing model | Paid | Paid |
| Free tier | No | No |
| Category | Generative AI | Generative AI |
Strengths and limits
Claude Opus 5.5
- Matches Claude Fable 5.1 on most work at a much lower price
- Faster output than Opus 5
- Strong on coding and knowledge work such as financial analysis
Watch out for
- Newest release, so fewer independent long-term evaluations
- Output still costs $20 per million tokens
- Sonnet or Haiku are cheaper for routine tasks
Claude Sonnet 5
- Lower price than Sonnet 4.6 with newer capabilities
- Fast enough for interactive use
- Handles most tasks that do not need Opus-level depth
Watch out for
- Below Opus on the hardest reasoning tasks
- Sonnet 5.5 is announced as coming soon
- Image generation is not built in
Key features
Claude Opus 5.5
- 1M-token context window at standard pricing
- Agentic coding, code review and bug detection
- Computer use and complex multi-step tasks
- Clearer, more direct communication style
- Available in Claude apps, the API, Claude Code, AWS, Google Cloud and Microsoft Azure
Claude Sonnet 5
- Balanced speed and quality for everyday work
- Strong on drafting, analysis and code review
- Computer use and tool use
- Batch pricing at half the standard rate
- Available through Claude apps, the API and major clouds
Pricing compared
Claude Opus 5.5 is priced by usage rather than by seat: API: $4 in / $20 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing.
Claude Sonnet 5 is priced by usage rather than by seat: API: $2 in / $10 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing.
Profession-fit verdict
8 roles where both tools are recommended. A higher relevance score means a better fit for that job.
| Profession | Claude Opus 5.5 score | Claude Sonnet 5 score |
|---|---|---|
| Nurse | 9/10 | 8/10 |
| Doctor | 9/10 | 8/10 |
| Dentist | 9/10 | 8/10 |
| Pharmacist | 9/10 | 8/10 |
| Physical Therapist | 9/10 | 8/10 |
| Mental Health Counselor | 9/10 | 8/10 |
| Veterinarian | 9/10 | 8/10 |
| Medical Coder | 9/10 | 8/10 |
Frequently asked questions
Which is better, Claude Opus 5.5 or Claude Sonnet 5?
It depends on the work. Claude Opus 5.5 stands out for matches Claude Fable 5.1 on most work at a much lower price. Claude Sonnet 5 stands out for lower price than Sonnet 4.6 with newer capabilities. Across 8 professions where both are rated, Claude Opus 5.5 ranks higher more often (8 roles).
How do Claude Opus 5.5 and Claude Sonnet 5 compare on price?
Claude Opus 5.5 is priced by usage rather than by seat: API: $4 in / $20 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing. Claude Sonnet 5 is priced by usage rather than by seat: API: $2 in / $10 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing.
Is there a free option between Claude Opus 5.5 and Claude Sonnet 5?
Neither lists a permanent free tier. Look for trials or usage-based pricing to test on real work first.