Claude Sonnet 5.5 vs GPT-6.1 Sol
A side-by-side look at Claude Sonnet 5.5 from Anthropic and GPT-6.1 Sol from OpenAI: list prices, context windows, licensing and capabilities, with monthly costs worked out for three common workloads.
The short version
- Price: effectively tied on blended list price.
- Larger context window: GPT-6.1 Sol (1.05M vs 1M tokens).
- Inputs: Claude Sonnet 5.5 accepts text, images, pdf; GPT-6.1 Sol accepts text, images.
- Newer release: GPT-6.1 Sol (September 29, 2026).
Specs side by side
| Claude Sonnet 5.5 | GPT-6.1 Sol | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Released | Sep 28, 2026 | Sep 29, 2026 |
| Status | Current | Current |
| Weights and license | Closed Proprietary | Closed Proprietary |
| Tier | Advanced | Advanced |
| Context window | 1M | 1.05M |
| Max output | 125K | 125K |
| Input per 1M tokens | $2 | $2 |
| Output per 1M tokens | $10 | $10 |
| Cached input per 1M | $0.10 | $0.10 |
| Input types | Text, Images, PDF | Text, Images |
| Reasoning mode | Yes | Yes |
| Tool calling | Yes | Yes |
| Parameters | Undisclosed | Undisclosed |
Highlighted cells are better on that line: lower price or larger limit. List prices, standard tier, checked October 10, 2026.
What they cost for real workloads
| Workload (monthly) | Claude Sonnet 5.5 | GPT-6.1 Sol | Difference |
|---|---|---|---|
| Support chatbot30,000 conversations a month, 2,000 input and 400 output tokens each | $240 | $240 | |
| Document summaries2,000 documents a month, 12,000 input and 800 output tokens each | $64 | $64 | |
| Coding agent1,000 tasks a month, 60,000 input and 6,000 output tokens each | $180 | $180 |
Standard rates without caching or batch discounts. Try your own volumes.
Choose Claude Sonnet 5.5 if
- you mainly need it for chat, writing, which Anthropic emphasizes for this model
- your inputs include pdf
- half the per-token price of Claude Opus 5.5
- 1M-token context window and 128K-token output limit
Choose GPT-6.1 Sol if
- you mainly need it for reasoning, enterprise, which OpenAI emphasizes for this model
- you need more than 1M tokens of context in one request
- $2 input and $10 output per million tokens, with cached input at $0.10
- 1.05M-token context window
Our take
Both are positioned for agents, coding. On list price the gap is about 1.0×, which matters most for high-volume, input-heavy workloads. Quality differences shift with every release, so treat this page as a shortlist tool: run 20-50 of your real tasks through both, score the outputs, and divide the bill by the number of tasks each one got right.
Read the full profiles: Claude Sonnet 5.5 and GPT-6.1 Sol. For help designing that test, see how to read LLM benchmarks.
Frequently asked questions
Which is cheaper, Claude Sonnet 5.5 or GPT-6.1 Sol?
GPT-6.1 Sol has the lower list price: $2 input and $10 output per million tokens, versus $2 and $10. Discounts for caching and batch processing can change the real bill, so price your own token mix.
Which has the bigger context window?
GPT-6.1 Sol accepts 1.05M tokens, compared with 1M for Claude Sonnet 5.5.
Can I run Claude Sonnet 5.5 or GPT-6.1 Sol on my own hardware?
Claude Sonnet 5.5 is closed, so only through hosted APIs. GPT-6.1 Sol is closed, so only through hosted APIs.
Is Claude Sonnet 5.5 better than GPT-6.1 Sol?
It depends on the task. Public benchmarks and arena rankings move with every release and rarely match a specific workload. Use the specs here to shortlist, then test both on your own prompts and compare accuracy, latency and cost per correct answer.
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