Documentation-based comparison
Claude Sonnet 5.5 versus GPT-6.1 Sol
Compare documented scope and conditions. Unknowns remain unknown; different billing units do not establish a cost winner.
What the evidence answers
A reading of reviewed official documentation for Claude Sonnet 5.5 and GPT-6.1 Sol. It is not a hands-on test, a ranking or a recommendation of one product.
Price
- Claude Sonnet 5.5 Usage-based API pricing
- GPT-6.1 Sol Usage-based API pricing
These prices use differently defined usage units. Read each with its own unit and conditions; they do not add up to one total or a cheaper product.
Documented for both
- Provider
- Claude Sonnet 5.5 Anthropic
- GPT-6.1 Sol OpenAI
- API model identifier
- Claude Sonnet 5.5 claude-sonnet-5-5
- GPT-6.1 Sol gpt-6.1-sol
- Modalities
- Claude Sonnet 5.5 Text and image input; text output
- GPT-6.1 Sol Text and image input; text output
- Context window
- Claude Sonnet 5.5 1M tokens in the context window
- GPT-6.1 Sol 1,050,000 tokens in the context window
- Maximum output
- Claude Sonnet 5.5 128K output tokens (standard API)
- GPT-6.1 Sol 128,000 output tokens
- Input token rate
- Claude Sonnet 5.5 2 USD per million base input tokens
- GPT-6.1 Sol 2 USD per million input tokens
- Output token rate
- Claude Sonnet 5.5 10 USD per million output tokens
- GPT-6.1 Sol 10 USD per million output tokens
- Availability
- Claude Sonnet 5.5 Active model; released 28 September 2026.
- GPT-6.1 Sol Listed for paid API usage tiers; Free tier is not supported.
Limits to check
- Claude Sonnet 5.5 The standard output ceiling is 128K tokens; the documented 300K batch option requires a separate beta header. Thinking and tool behavior are model-specific.
- GPT-6.1 Sol The 1,050,000-token context window and 128,000-token output ceiling are different limits. Long prompts and premium service tiers change token rates.
Not verified yet
Every compared requirement has evidence for at least one.
Not verified means our reviewed sources do not establish it. It does not mean a product lacks the capability or that it costs nothing.
Next steps
| Requirement | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| Pricing | Usage-based API pricing | Usage-based API pricing |
| Who it is for | An Anthropic Claude model with text and image inputs and text output. Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | An OpenAI model accepting text and images and producing text. Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Coverage limits | The standard output ceiling is 128K tokens; the documented 300K batch option requires a separate beta header. Thinking and tool behavior are model-specific. Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | The 1,050,000-token context window and 128,000-token output ceiling are different limits. Long prompts and premium service tiers change token rates. Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Provider | Anthropic Provider identity is linked to the separate Anthropic Claude API entry. Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | OpenAI Provider identity is linked to the separate OpenAI API catalogue entry. Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| API model identifier | claude-sonnet-5-5 Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | gpt-6.1-sol Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Modalities | Text and image input; text output Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | Text and image input; text output Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Context window | 1M tokens in the context window Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | 1,050,000 tokens in the context window Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Maximum output | 128K output tokens (standard API) Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | 128,000 output tokens Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Input token rate | 2 USD per million base input tokens Standard base input rate for Claude Sonnet 5.5. Prompt cache writes/reads and batch processing have separate rates; tools, service tier and taxes can change the total. Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | 2 USD per million input tokens Standard uncached text input for prompts up to 272K input tokens. Longer prompts: 2x input/cache and 1.5x output for the full request. Fast 2x, Ultrafast 6x; regional processing adds 10% where available. Cache writes, tools and tax are additional scopes. Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Output token rate | 10 USD per million output tokens Standard output rate for Claude Sonnet 5.5. Compare the exact consumption option; the batch discount is separate. Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | 10 USD per million output tokens Standard text output for prompts up to 272K input tokens. Above 272K input tokens: 1.5x output rate. Fast, Ultrafast, regional processing, tools and tax can change the total. Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Availability | Active model; released 28 September 2026. Vendor lifecycle status checked on 18 October 2026; account and platform eligibility require confirmation. Verified Oct 18, 2026 · Claude Sonnet 5.5: official API documentation | Listed for paid API usage tiers; Free tier is not supported. Published rate-limit table, not a verification of regional eligibility or access for a particular account. Verified Oct 18, 2026 · GPT-6.1 Sol: official API documentation |
| Coverage note | Official documentation checked on 18 October 2026; no hands-on test. | Official documentation checked on 18 October 2026; no hands-on test. |