GPT-6.1 Sol vs Claude Sonnet 5.5: API price, context and cost per task
The two mid-tier workhorses released a day apart at the end of September 2026: Anthropic's Claude Sonnet 5.5 (28 September) and OpenAI's GPT-6.1 Sol (29 September).
Today both list at $2 per million input tokens and $10 per million output tokens. GPT-6.1 Sol reads more per request: 1,050,000 tokens against 1,000,000.
Data updated 2026-11-11 - source: public OpenRouter model list, refreshed daily. Prices in USD, excluding VAT.
Specs and prices side by side
| GPT-6.1 Sol | Claude Sonnet 5.5 | |
|---|---|---|
| Vendor | OpenAI | Anthropic |
| Input, per 1M tokens | $2 | $2 |
| Output, per 1M tokens | $10 | $10 |
| Cached input, per 1M | $0.1 | $0.1 |
| Batch (input / output) | $1 / $5 | $1 / $5 |
| Context window | 1,050,000 | 1,000,000 |
| Max output | 128,000 | 128,000 |
| Input types | text, images, files | text, images, files |
| Reasoning | Yes | Yes |
| Tool calling | Yes | Yes |
| On OpenRouter since | 29 Sep 2026 | 28 Sep 2026 |
Highlighted: the cheaper price or the larger limit. "Not published" means the figure is not in the public model listing yet.
What a month of work costs
Four typical workloads at today's list prices. Reasoning models also bill their thinking as output tokens, so treat output-heavy numbers as a floor.
| Workload | GPT-6.1 Sol | Claude Sonnet 5.5 | Difference |
|---|---|---|---|
| Support chatbot10,000 conversations a month, about 1,500 input and 400 output tokens each | $70 | $70 | same |
| Coding agent300 tasks a month, about 80,000 input tokens (code context re-read across steps) and 8,000 output tokens each | $72 | $72 | same |
| Coding agent with caching70% of input served from the prompt cache | $40.08 | $40.08 | |
| Long-document analysis1,000 documents a month, about 50,000 tokens in and a 1,500-token summary out | $115 | $115 | same |
| Content drafting600 articles a month, about 3,000 tokens of brief in and 2,500 tokens of draft out | $18.60 | $18.60 | same |
Price stability over the last 30 days
- GPT-6.1 Sol: no change in the last 30 days.
- Claude Sonnet 5.5: no change in the last 30 days.
What the vendors and benchmarks say
GPT-6.1 Sol
"GPT-6.1 Sol is an upgrade to GPT-6 Sol from OpenAI, positioned below the flagship GPT-6 Astra in the GPT-6 series."model card on OpenRouter
- Listed on OpenRouter on 29 September 2026, one week after GPT-6 Sol, which it upgrades. Source: OpenRouter
Claude Sonnet 5.5
"Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade."model card on OpenRouter
- Listed on OpenRouter on 28 September 2026 as the direct successor to Claude Sonnet 5. Source: OpenRouter
Which one to pick
Both launched in the same price band, so the bill differs mainly through cached-input pricing (see the table), token efficiency and how much each model reasons before answering. GPT-6.1 Sol has a slightly larger window; Sonnet 5.5 is Anthropic's model for well-scoped everyday work such as building features and fixing bugs. Pick by quality on your own prompts - price will not decide this one.
Cheaper models with a similar context window
Models from our comparison set that cost less than both on a blended basis and support tool calling. They are not equivalent in quality - test before switching.
- Qwen3.8 Max (Alibaba (Qwen)): $2 / $6 per million tokens, 1M context
- Gemini 3.8 Flash (Google): $0.825 / $4.13 per million tokens, 1.05M context
- DeepSeek V4 Pro (DeepSeek): $0.955 / $1.91 per million tokens, 1.05M context
Related reading
- GPT-6.1 Terra vs Claude Sonnet 5.5: Polish Test Results
- Gemini 4 Carbon test: 50+ tasks vs Argon, Claude Fable 5.2 and GPT-6.1 Sol
- Claude Fable 5.2 vs GPT-6.1 Sol vs Gemini 4 Argon: Price, Benchmarks
- Claude Sonnet 5.5: Pricing, Benchmarks, and Tested Performance
- Claude Sonnet 5.5 Context Window: 1 Million Token Capacity
How we calculate
Prices are the public per-token list rates from OpenRouter's model list, which match the vendors' own API prices for first-party models and show the current routed price for open-weight models served by several hosts. Monthly costs multiply those rates by the token volumes in each workload; caching assumes the stated share of input is billed at the cached-input rate. Benchmarks and claims are quoted from the named sources, mostly the vendors themselves - treat them as a guide and test on your own tasks. See also the AI cost calculator and all tracked model prices.
Frequently asked questions
Which is cheaper, GPT-6.1 Sol or Claude Sonnet 5.5?
As of 11 Nov 2026, GPT-6.1 Sol costs $2 per million input tokens and $10 per million output tokens; Claude Sonnet 5.5 costs $2 and $10. GPT-6.1 Sol is cheaper in 0 of the 4 monthly workloads we price on this page. The real bill also depends on how many reasoning tokens each model writes.
Which has the larger context window?
GPT-6.1 Sol reads up to 1,050,000 tokens and can write up to 128,000; Claude Sonnet 5.5 reads up to 1,000,000 and writes up to 128,000.
How much does a support chatbot cost on each model?
For 10,000 conversations a month (about 15 million input and 4 million output tokens) you would pay about $70 on GPT-6.1 Sol and $70 on Claude Sonnet 5.5 at list prices, before any caching or batch discounts.
Do they offer prompt caching or batch discounts?
GPT-6.1 Sol lists cached input at $0.1 per million and a batch rate of $1 / $5. Claude Sonnet 5.5 lists cached input at $0.1 per million and a batch rate of $1 / $5. Caching matters most for agents and chatbots that resend the same context on every turn.
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