GPT-6 Astra is OpenAI's top flagship and GPT-6.1 Sol the tier below it in the GPT-6 family. Both have 1M-token context and a long-context step at 272K, but Astra costs five times more on fresh tokens and ten times more on cache hits.
GPT-6.1 Sol is 5× cheaper on input and output and 10× cheaper on cache hits ($0.10 vs $1.00). For cache-heavy agents the real gap is wider than the headline 5×. Use Astra only where it measurably beats Sol on your hardest tasks.
| GPT-6 Astra | GPT-6.1 Sol | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Tier | Flagship | Mid-tier |
| Input / 1M tokens | $10.00 | $2.00 |
| Output / 1M tokens | $50.00 | $10.00 |
| Cache hit / 1M | $1.00 | $0.10 |
| Cache write / 1M | $12.50 | $2.50 |
| Context window | 1M | 1M |
| Notes | New top flagship (Sep 3, 2026); rolling out to Plus/Pro/Business/Enterprise; >272K tokens: $20/$75, cache $2 | New (Sep 29, 2026 DevDay), below Astra in the GPT-6 family; replaces GPT-6 Sol at the same input/output price with a 50% cheaper cache-read rate; >272K tokens: $4/$15, cache $0.20. ChatGPT Work/Codex on Plus/Pro/Business/Enterprise/Edu, plus API |
GPT-6.1 Sol is 5.0× cheaper on input tokens ($2.00 vs $10.00 per 1M). GPT-6.1 Sol is 5.0× cheaper on output tokens ($10.00 vs $50.00 per 1M).
| Workload | GPT-6 Astra | GPT-6.1 Sol | Difference |
|---|---|---|---|
| Support chatbot 10,000 conversations × (2,000 input + 400 output tokens) | $400 | $80.00 | GPT-6.1 Sol saves $320 |
| Document Q&A 1,000 questions × (30,000 input + 800 output tokens) | $340 | $68.00 | GPT-6.1 Sol saves $272 |
| Coding agent session 4M input tokens (90% cache hits) + 150,000 output tokens | $15.10 | $2.66 | GPT-6.1 Sol saves $12.44 |
Standard rates per 1M tokens from data on this site. The coding-agent row assumes 90% of input is read from the prompt cache (full input price where a model has no cache rate). Cache-write fees, batch discounts and long-context surcharges listed in the notes are not included. Updated November 2, 2026.
a task fails on Sol and succeeds on Astra in your evals, and the value of that success exceeds a 5× token bill — for example rare, high-stakes analyses rather than bulk traffic.
you want the GPT-6 family at a sustainable price for production — chat, coding agents and RAG — especially with large cached contexts.
Astra's cache hit is $1.00 per 1M versus Sol's $0.10, a 10× difference, because Sol's cache rate was halved when 6.1 replaced GPT-6 Sol. For a coding agent that resends a large repository context every turn, Astra costs far more than 5× Sol, as the coding-agent row shows. Cache writes are $12.50 vs $2.50.
Both step up above 272K input tokens: Astra to $20/$75 with $2 cache hits, Sol to $4/$15 with $0.20 cache hits. The ratio stays around 5× on input and output, so long prompts don't favour either — they just make Astra's absolute bill grow faster.
Run Sol by default and escalate to Astra on failure. Every 10% of output tokens shifted to Astra adds about 40% to the blended output rate, so keep escalation narrow. OpenAI's Batch API halves both models' rates, including long-context tiers; Astra is also rolling out to ChatGPT Plus, Pro, Business and Enterprise for interactive use.
5× on input and output ($10.00/$50.00 vs $2.00/$10.00 per 1M) and 10× on cache hits.
Yes. Astra rises to $20/$75 per 1M and Sol to $4/$15 for prompts over 272K tokens.
Yes. OpenAI's Batch API lists both models at half their standard rates.
How we choose: prices come from each vendor's official pricing page and are re-checked every week. We take no affiliate fees, so rankings aren't for sale.