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 5.5 vs GPT-6 Sol Pro: price, context and capabilities
Choose Claude Sonnet 5.5 for reused prompts and documents (RAG, agents); 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).
- GPT-6 Sol Pro reads more per request: 1.05M tokens against 1M.
- Only Claude Sonnet 5.5 offers batch api.
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 GPT-6 Sol Pro.
Monthly cost at three volumes
| Volume | Claude Sonnet 5.5 | GPT-6 Sol Pro | 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 5.5 | GPT-6 Sol Pro | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Category | Language models | Language models |
| Status | Generally available | 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 | $0.10 / 1M tokens | $0.20 / 1M tokens |
| Context window | 1M | 1.05M |
| Max output | 128k | 128k |
| Released | September 2026 | Sep 22, 2026 |
| Knowledge cutoff | June 2026 | No data |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching |
| API model id | claude-sonnet-5-5 | gpt-6-sol-pro |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol Pro |
|---|---|---|
| Intelligence Index | 56 | No data |
| SciCode | 61% | No data |
| Humanity's Last Exam | 55% | No data |
| Long-context reasoning (AA-LCR) | 82.7% | 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 5.5 or GPT-6 Sol Pro?
Choose Claude Sonnet 5.5 for reused prompts and documents (RAG, agents); on the other points the two are level or the data is missing.
Which is cheaper, Claude Sonnet 5.5 or GPT-6 Sol Pro?
Both cost the same at the headline price ($4.00 / 1M tokens).
Which has the larger context window, Claude Sonnet 5.5 or GPT-6 Sol Pro?
GPT-6 Sol Pro reads more per request: 1.05M tokens against 1M.
What is the difference between Claude Sonnet 5.5 and GPT-6 Sol Pro?
Claude Sonnet 5.5 is made by Anthropic and GPT-6 Sol Pro by OpenAI. Both cost the same at the headline price ($4.00 / 1M tokens). GPT-6 Sol Pro reads more per request: 1.05M tokens against 1M. Only Claude Sonnet 5.5 offers batch api.
How much do Claude Sonnet 5.5 and GPT-6 Sol Pro cost per month?
At 20 million input and 5 million output tokens a month, Claude Sonnet 5.5 costs $90.00 and GPT-6 Sol Pro costs $90.00, at standard rates.