GPT-6.1 Sol vs GPT-6 Astra: Is Astra Worth 5x the Price?
Last verified: October 14, 2026. All figures come from OpenAI's official pages linked below and are vendor-reported; we have not run independent benchmarks.
OpenAI now sells two serious models for hard work. GPT-6 Astra is the flagship, launched in early September; its HN thread reached 2,279 points (Hacker News). GPT-6.1 Sol arrived on September 29 with the pitch "Near-Astra intelligence for a fifth of the price" (1,067 points on Hacker News). The question is simple: when is Astra worth five times the price?
| Criterion | GPT-6.1 Sol | GPT-6 Astra |
|---|---|---|
| Input / output (per 1M tokens) | $2 / $10 | $10 / $50 |
| Cached input | $0.10 | $1.00 |
| Cache writes | $2.50 | $12.50 |
| Context window | 1,050,000 (922K max input) | 1,050,000 (922K max input) |
| Max output | 128,000 | 128,000 |
| Knowledge cutoff | Apr 30, 2026 | Apr 30, 2026 |
| Reasoning effort | low → max | low → max |
| Speed options | Fast (2x price), Ultrafast (6x price) | Fast (2x price) |
| API model ID | gpt-6.1-sol | gpt-6-astra |
Sources: GPT-6.1 Sol docs, GPT-6 Astra docs.
Practical rule: the specs are nearly identical. You are paying 5x for capability, so measure capability on your own tasks.
Why "which is smarter" is the wrong question
Astra is smarter. OpenAI says so itself: Astra is "our most capable model for the most demanding work," and Sol is "near-Astra." The real question is how big the gap is on your tasks, and whether closing it is worth $40 extra per million output tokens.
Both models share the same context window, output limit, knowledge cutoff, input modalities (text and image) and Responses API tools: web search, file search, code interpreter, computer use, MCP and more. Both also bill prompts over 272K input tokens at 2x input and 1.5x output, and both offer Batch and Flex at 50% off (Sol docs, Astra docs).
How close Sol gets: OpenAI's own numbers
The GPT-6.1 Sol announcement frames every result against Astra (all vendor-reported):
| Area | What OpenAI reports for Sol vs Astra |
|---|---|
| Coding (DeepSWE v1.1) | Sol "matches GPT-6 Astra at roughly one-fifth of the cost" |
| Professional documents (GDP.pdf) | Sol "approaches GPT-6 Astra's state-of-the-art performance at roughly one-fifth the cost per task" |
| Computer use (OSWorld 2.0 offline) | Sol is "within 2.1 percentage points of Astra's score at maximum reasoning effort at roughly one-seventh the cost per task" |
| Science (Terminal-Bench Science 0.1) | Astra scores highest at 68.1%; Sol costs $5.47 per task vs $23.80 for Astra |
| Factuality | Sol's error rate "remains within 1.9 percentage points of GPT-6 Astra's, at less than one-fifth the cost per task" |
OpenAI's own advice: Astra "should be used for the most difficult scientific research tasks."
Where Astra is clearly ahead
The Astra launch post reports frontier results that the Sol post doesn't claim to match, for example:
- 97.6% on FrontierMath Tier 4 (v2)
- 99.9% on ARC-AGI-3
- 100% on ExploitBench
- 57.9% on Terminal-Bench 4.0
OpenAI also says Astra "meets the Critical threshold in cybersecurity under our Preparedness Framework," and that it ships with stricter cyber safeguards.
Vendor tables are run by the vendor. Small gaps should be re-tested on your own work before you pay 5x.
What early users say
Reactions on X are mixed:
- Paul Bohm called GPT-6.1 Sol "the first model that offers almost-frontier capability at ~1/10th the cost" (post).
- Chad Moran gave "the same (relatively easy) task to GPT 6.1 Sol and GPT 6.0 Astra" and wrote "GPT 6.1 Sol failed spectacularly" (post).
Watch on YouTube: "I Tested GPT-6.1 Sol vs Astra. Here's What I'd Use" by Mark Kashef
Third-party video by Mark Kashef, an independent creator. AI Takeaway did not make this video and is not affiliated with its creator.
No time to watch the whole review? AI Takeaway is a tool that works on any YouTube video, including third-party reviews like this one. Paste the link to get the key points in minutes, jump to the original timestamps, and ask follow-up questions; every answer cites the video. You can also browse the AI Takeaway video summary hub for more AI and tech interviews.
Which one to choose
Everyday coding agents and high-volume professional work
Choose Sol. OpenAI reports parity on DeepSWE and near-parity on documents and computer use, at a fraction of the cost.
Latency-critical work
Choose Sol with Ultrafast mode. OpenAI says it offers up to 8x faster token generation in Codex. It costs 6x the Standard price (docs).
The hardest research, math and science problems
Choose Astra. OpenAI itself recommends it for the most difficult scientific research tasks.
Security research
Both models ship with cyber safeguards. Astra has the stronger capabilities, but OpenAI says it "will refuse to comply with more advanced cybersecurity tasks such as creating proof-of-concept exploits," with broader access planned through OpenAI Daybreak.
ChatGPT users
OpenAI says Sol is available to Plus, Pro, Business, Enterprise and Edu users in ChatGPT Work and Codex, but "not yet available in Chat" (OpenAI).
Practical checklist
- Default to Sol, and route only proven-hard tasks to Astra.
- Run 50–100 real tasks on both, at matched reasoning effort.
- Compare cost per finished task, not per token.
- Use cached input heavily: $0.10 on Sol vs $1.00 on Astra.
- Re-check both pricing pages before committing.
Practical rule: Sol by default, Astra by exception.
Keep up without the watch time
OpenAI ships new models and modes almost weekly. If you would rather read than watch, the AI Takeaway video summary hub has free curated summaries of AI and tech interviews, for example:
- Sam Altman on Astra, AGI, and the future of OpenAI
- OpenAI Codex lead on the new shape of product work (Andrew Ambrosino)
- Sam Altman on AGI, Compute, and Human Agency
To keep up with ongoing AI news, check the Hub regularly. You can also install the AI Takeaway Chrome extension to get key points right on YouTube, or submit any YouTube video yourself on aitakeaway.net.
For more model guides and comparisons, browse all AI Takeaway articles, including our guide to Google's rival flagship, Gemini 4 Argon.
FAQ
How much cheaper is GPT-6.1 Sol than GPT-6 Astra?
Sol lists $2 input and $10 output per million tokens; Astra lists $10 and $50. That makes standard input and output 5x cheaper on Sol, and cached input 10x cheaper ($0.10 vs $1.00).
Is GPT-6.1 Sol as good as GPT-6 Astra?
Close, but not equal. OpenAI reports Sol matching Astra on DeepSWE v1.1 and coming within 2.1 points on OSWorld 2.0. OpenAI still recommends Astra for the hardest scientific work.
Do they have the same context window?
Yes. Both list a 1,050,000-token context window, 922,000 max input tokens and 128,000 max output tokens.
Can I use GPT-6.1 Sol in ChatGPT?
Yes, in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise and Edu users. At launch, OpenAI said it was not yet available in Chat.
Sources
- OpenAI, Introducing GPT-6.1 Sol (Sep 29, 2026)
- OpenAI, GPT-6 Astra: A new generation of intelligence
- OpenAI developer docs: GPT-6.1 Sol, GPT-6 Astra
- Hacker News: GPT-6 Astra, GPT-6.1 Sol
- Posts on X: Paul Bohm, Chad Moran