GPT-6 Astra vs GPT-6.1 Sol: is OpenAI's top model worth five times the price?

The short answer: Sol as the default, Astra as the escalation

Choose GPT-6.1 Sol for most hard work: it lists $2 input and $10 output per million tokens, and OpenAI's Plus estimates allow roughly three times as many local messages as Astra. Choose GPT-6 Astra when Sol still fails your checks; OpenAI calls Astra its most capable model and says Astra at Low effort can outperform Sol at High. Astra also appears in Chat as GPT-6 Pro on higher plans.

Scope and evidence

Task: choosing between OpenAI's two top models for coding, research and analysis in the API or ChatGPT. Prices are in US dollars from OpenAI's model pages, the GPT-6 models help article and the Work and Codex usage guide; index results and cost per task come from Artificial Analysis's v5 article, which we consulted on October 28, 2026.

AppFor.ai has not run these models side by side; every number here is either OpenAI's or Artificial Analysis's.

Compare the same criteria

Each line compares OpenAI's flagship with its mid-tier model and then spells out the consequence.

• API price per million tokens. Astra: $10 input, $1 cached, $50 output. Sol: $2 input, $0.10 cached, $10 output. What this means: Astra is five times the price.
• Intelligence Index v5 at max effort. Astra: 57. Sol: 55. What this means: a 2-point gap.
• Cost per index task at max effort. Astra: $6.24. Sol: $1.27. What this means: nearly five times more per finished task.
• Where each leads. Astra: Terminal-Bench-Science 63% at max effort and CritPt v2 hard subset 72% at high effort. Sol: 58% and 69% on the same tests, both at max effort. What this means: Astra's edge shows most on science tasks.
• Reasoning effort. Astra: low, medium, high, xhigh and max; OpenAI's pages checked do not state a default. Sol: low to max, default medium. What this means: same range.
• Knowledge and context. Both: April 30, 2026 cutoff, 1.05M context, 128K output. What this means: no difference.
• ChatGPT access. Astra: Work and Codex from Plus, 5 to 45 local messages per five hours estimated; GPT-6 Pro in Chat on Pro $100, Pro $200, Business and Enterprise. Sol: Work and Codex, 15 to 160. What this means: Sol stretches the allowance further.

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Which fits your real work?

A Plus subscriber coding in Codex all afternoon. Sol fits, because the same allowance covers roughly three times as many local messages.

A lab running research-level physics problems with code. Astra fits on its CritPt v2 and Terminal-Bench-Science results.

A Pro subscriber who wants the top OpenAI model in a chat window. Astra fits as GPT-6 Pro in Chat.

Cost of getting the work done

API: 2 million input and 200,000 output tokens cost $30 on Astra and $6 on Sol before caching; Batch and Flex halve both. Artificial Analysis measured $6.24 against $1.27 per index task at max effort.

ChatGPT: Plus at $20 a month includes both in Work and Codex from one shared allowance, where Astra uses more of it per task. GPT-6 Pro in Chat starts with Pro at $100 a month.

Try both on the same small task

Suggested check: follow OpenAI's own hint and compare Astra at Low effort with Sol at High on one difficult task.

• The explanation identifies a real race or ordering problem you can confirm.
• The new test fails reliably before the fix and passes after it.
• Only scheduler code and its tests change.
• Compare usage in Settings, Usage or the API token counts for both runs.

Decision checklist

Apply the lines that match. Specs are in our GPT-6 Astra profile and our GPT-6.1 Sol profile.

• If you want the most work per dollar or per allowance, start with Sol.
• If Sol at high effort fails, try Astra at Low or Medium.
• If your work is research-level science with code, test Astra.
• If you need the model in Chat, Astra is GPT-6 Pro on higher plans.
• If you pay per token, budget five times more for Astra.

Go a little further

Related reading

• GPT-6 Astra profile →
• GPT-6.1 Sol profile →
• How to use GPT-6 Astra in ChatGPT →