High-volume, cost-sensitive work
Either one
Both cost $4.00 per million tokens on a typical mix of three input tokens for every output token.
Claude Sonnet 5 vs Claude Sonnet 5.5: price, context and capabilities
Choose Claude Sonnet 5.5 for reused prompts and documents (RAG, agents), the hardest reasoning tasks and the latest release; on the other points the two are level or the data is missing.
In short
- Both cost the same at the headline price ($4.00 / 1M tokens).
- Both accept 1M tokens per request.
- Claude Sonnet 5.5 is the newer model (September 2026, against June 2026).
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Reused prompts and documents (RAG, agents)
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 charges $0.10 per million cached input tokens, against $0.20 for Claude Sonnet 5.
Hardest reasoning tasks
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 scores 56 on the Artificial Analysis Intelligence Index, against 38.2 for Claude Sonnet 5.
Reasoning over long documents
Either one
They are practically level on Long-context reasoning (AA-LCR) (82% and 82.7%).
Latest release
Choose Claude Sonnet 5.5
Claude Sonnet 5.5 is the newer release (September 2026, against June 2026 for Claude Sonnet 5).
Monthly cost at three volumes
| Volume | Claude Sonnet 5 | Claude Sonnet 5.5 | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $4.50 | $4.50 | = |
| Production: 20M input, 5M output tokens | $90.00 | $90.00 | = |
| Scale: 500M input, 100M output tokens | $2,000 | $2,000 | = |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| Claude Sonnet 5 | Claude Sonnet 5.5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Category | Language models | Language models |
| Status | Legacy | Generally available |
| Headline price | $4.00 / 1M tokens | $4.00 / 1M tokens |
| Input | $2.00 / 1M tokens | $2.00 / 1M tokens |
| Output | $10.00 / 1M tokens | $10.00 / 1M tokens |
| Cached input | $0.20 / 1M tokens | $0.10 / 1M tokens |
| Context window | 1M | 1M |
| Max output | 128k | 128k |
| Released | June 2026 | September 2026 |
| Knowledge cutoff | No data | June 2026 |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | claude-sonnet-5 | claude-sonnet-5-5 |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Sonnet 5 | Claude Sonnet 5.5 |
|---|---|---|
| Intelligence Index | 38.2 | 56 |
| SciCode | 54.3% | 61% |
| Humanity's Last Exam | 41.3% | 55% |
| Long-context reasoning (AA-LCR) | 82% | 82.7% |
| GPQA Diamond | 91.1% | No data |
| MMMU-Pro (visual reasoning) | 77.3% | No data |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose Claude Sonnet 5 or Claude Sonnet 5.5?
Choose Claude Sonnet 5.5 for reused prompts and documents (RAG, agents), the hardest reasoning tasks and the latest release; on the other points the two are level or the data is missing.
Which is cheaper, Claude Sonnet 5 or Claude Sonnet 5.5?
Both cost the same at the headline price ($4.00 / 1M tokens).
Which has the larger context window, Claude Sonnet 5 or Claude Sonnet 5.5?
Both accept 1M tokens per request.
What is the difference between Claude Sonnet 5 and Claude Sonnet 5.5?
Claude Sonnet 5 is made by Anthropic and Claude Sonnet 5.5 by Anthropic. Both cost the same at the headline price ($4.00 / 1M tokens). Both accept 1M tokens per request. Claude Sonnet 5.5 is the newer model (September 2026, against June 2026).
How much do Claude Sonnet 5 and Claude Sonnet 5.5 cost per month?
At 20 million input and 5 million output tokens a month, Claude Sonnet 5 costs $90.00 and Claude Sonnet 5.5 costs $90.00, at standard rates.
Which is newer, Claude Sonnet 5 or Claude Sonnet 5.5?
Claude Sonnet 5.5 was released on September 2026 and Claude Sonnet 5 on June 2026.