GPT-6.1 Sol vs GPT-6 Astra: API price, context and cost per task
Two tiers of OpenAI's GPT-6 family. Astra is the flagship; GPT-6.1 Sol is the upgraded high-end model positioned just below it.
On output, GPT-6.1 Sol is 5x cheaper ($10 vs $50 per million tokens). On input, GPT-6.1 Sol is 5x cheaper ($2 vs $10 per million tokens).
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 | GPT-6 Astra | |
|---|---|---|
| Vendor | OpenAI | OpenAI |
| Input, per 1M tokens | $2 | $10 |
| Output, per 1M tokens | $10 | $50 |
| Cached input, per 1M | $0.1 | $1 |
| Batch (input / output) | $1 / $5 | $5 / $25 |
| Context window | 1,050,000 | 1,050,000 |
| 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 | 4 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 | GPT-6 Astra | Difference |
|---|---|---|---|
| Support chatbot10,000 conversations a month, about 1,500 input and 400 output tokens each | $70 | $350 | GPT-6.1 Sol 5x cheaper |
| Coding agent300 tasks a month, about 80,000 input tokens (code context re-read across steps) and 8,000 output tokens each | $72 | $360 | GPT-6.1 Sol 5x cheaper |
| Coding agent with caching70% of input served from the prompt cache | $40.08 | $209 | |
| Long-document analysis1,000 documents a month, about 50,000 tokens in and a 1,500-token summary out | $115 | $575 | GPT-6.1 Sol 5x cheaper |
| Content drafting600 articles a month, about 3,000 tokens of brief in and 2,500 tokens of draft out | $18.60 | $93 | GPT-6.1 Sol 5x cheaper |
Price stability over the last 30 days
- GPT-6.1 Sol: no change in the last 30 days.
- GPT-6 Astra: 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
GPT-6 Astra
"GPT-6 Astra is OpenAI's flagship model for demanding end-to-end work."model card on OpenRouter
- OpenAI's flagship, presented on 3 September 2026 and rolled out in stages. Source: OpenAI
- Terminal-Bench 4.0: 57.9% (figure reported by OpenAI); GDPval-AA v2.1: 1542 Elo. Source: Anthropic's Claude Opus 5.5 launch comparison
Which one to pick
Astra costs several times more per token than Sol. OpenRouter's model card positions GPT-6.1 Sol for agentic coding, computer use and document-heavy professional work, which covers most production workloads. Keep Astra for the tasks where Sol measurably falls short in your own evals, and route everything else to Sol.
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 Astra Halted: OpenAI Won’t Release Model Over Safety
- 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
- GPT-6.1 Terra vs Claude Sonnet 5.5: Polish Test Results
- Claude Fable 5.2 vs GPT-6 Astra and Gemini 4 Carbon
- Claude Opus 5.5 vs GPT-6 Astra: Plan or API?
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 GPT-6 Astra?
As of 11 Nov 2026, GPT-6.1 Sol costs $2 per million input tokens and $10 per million output tokens; GPT-6 Astra costs $10 and $50. GPT-6.1 Sol is cheaper in 4 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; GPT-6 Astra reads up to 1,050,000 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 $350 on GPT-6 Astra 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. GPT-6 Astra lists cached input at $1 per million and a batch rate of $5 / $25. Caching matters most for agents and chatbots that resend the same context on every turn.
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