GPT-5.6 Sol — Specs, Pricing & Limits
Promotional pricing: OpenAI lowered GPT-5.6 Sol's prices on 2026-08-21 and says the promotional pricing is available at least through 2026-11-21. In ChatGPT plans it applies to usage paid with purchased credits; included plan usage and the 5-hour and weekly limits did not change.
Specs
| Status | Priced |
|---|---|
| Released (API changelog) | 2026-07-09 |
| Context window | 1,050,000 tokens |
| Max output | 128,000 tokens |
| Knowledge cutoff | Feb 16, 2026 |
| Reasoning effort levels | none, low, medium (default), high, xhigh, max |
| Long-context rule | >272,000 input tokens: 2x input, 1.5x output (full request) |
| Cache writes | Billed at the cache-write rate instead of the input rate |
| ChatGPT credit rate (per 1M) | 100 in · 10 cached · 500 out |
Pricing per 1M tokens, every published service tier
| Standard — short context | in $4.00 · cached $0.40 · writes $5.00 · out $20.00 |
|---|---|
| Standard — long context | in $8.00 · cached $0.80 · writes $10.00 · out $30.00 |
| Batch — short context | in $2.00 · cached $0.20 · writes $2.50 · out $10.00 |
| Batch — long context | in $4.00 · cached $0.40 · writes $5.00 · out $15.00 |
| Flex — short context | in $2.00 · cached $0.20 · writes $2.50 · out $10.00 |
| Flex — long context | in $4.00 · cached $0.40 · writes $5.00 · out $15.00 |
| Fast — short context | in $8.00 · cached $0.80 · writes $10.00 · out $40.00 |
| Fast — long context | in $16.00 · cached $1.60 · writes $20.00 · out $60.00 |
| Cache writes, 12-hour lifetime | $10.00 Standard short · $20.00 long — 2.5× the tier's input rate, instead of 1.25× for the default 30-minute lifetime (Responses API) |
Rate limits by usage tier
| Free | Not supported |
|---|---|
| Build | 5,000 RPM · 1,000,000 TPM · 3,000,000 batch queue |
| Launch | 10,000 RPM · 4,000,000 TPM · 200,000,000 batch queue |
| Grow | 15,000 RPM · 40,000,000 TPM · 15,000,000,000 batch queue |
GPT-5.6 Sol was the Codex CLI's default model until GPT-6.1 Sol replaced it, and it remains the model the unsuffixed gpt-5.6 alias routes to — so anything in your config or scripts that still says gpt-5.6 is running Sol, at Sol's prices, whether or not anyone meant it to.
Those prices are the second thing to know. OpenAI cut Sol's rates in August and labels them promotional, available at least through November 21, 2026, with nothing published about what happens after that. The table above shows today's rates; a budget built on them should carry an expiry date of its own. Inside ChatGPT plans the same promotion applies only to usage paid for with purchased credits — included plan usage and the 5-hour and weekly limits did not change.
Against the GPT-6 models, Sol now sits in an awkward middle. GPT-6.1 Sol, its successor as the CLI default, undercuts it on every Standard price cell and carries a newer knowledge cutoff, while sharing its context window and its request and token limits at every usage tier. The case for staying on GPT-5.6 Sol is behavioral continuity on a workload you've already tuned — reasoning effort here accepts both none and max, which GPT-6.1 Sol does not fully match.
Modality-wise, Sol takes text and image input and produces text; audio and video are not supported. Its long-context rule reprices the whole request once input crosses the threshold, not just the excess.
The table above is computed directly from this site's facts module: every published service tier with its short- and long-context band, the effort levels, and the rate-limit table.
Verified 2026-10-28 against https://developers.openai.com/api/docs/models/gpt-5.6-sol.
Could not confirm: What GPT-5.6 Sol will cost after the promotional window. OpenAI states only that the promotion lasts at least through 2026-11-21.
Checked: https://developers.openai.com/api/docs/models/gpt-5.6-sol · https://developers.openai.com/api/docs/pricing · https://developers.openai.com/api/docs/changelog · https://help.openai.com/en/articles/11481834-chatgpt-rate-card-business-enterpriseedu-credit-based-pricing