Decision summary
- New Sol route -> GPT-6 Sol
- Pinned gpt-5.6-sol with passing evals -> stay until the replay
- Lower published short-context list price -> GPT-6 Sol
- Need Astra -> do not stop at Sol
- High-volume -> GPT-6 Luna, not GPT-5.6 Sol
OpenAI Sol successor comparison
Frontier comparisonGPT-6 Sol vs GPT-5.6 Sol
GPT-6 Sol is the September 22, 2026 successor in the Sol tier.
Featured · Updated today · Last verified: September 2026
Choose GPT-6 Sol when
New Sol-tier coding and agent routes.
Choose GPT-5.6 Sol when
Pinned gpt-5.6-sol deployments and the prior Sol default.
- New Sol route: GPT-6 Sol
- Pinned gpt-5.6-sol with passing evals: stay until the replay
- Lower published short-context list price: GPT-6 Sol
Decision axes: Best for · Access and platforms · Context window · Input and output
Reasoning
GPT-6 Sol documents none through max. Re-check GPT-5.6 Sol's card rather than copying that ladder.
Coding
GPT-6 Sol is the new Sol-tier ID. Quality versus GPT-5.6 Sol is not scored here.
Multimodal
Text and image in, text out.
Speed
Confirm Fast mode on each card. Do not copy GPT-6 multipliers onto GPT-5.6.
Enterprise
Product entitlements such as Daybreak do not move just because the Sol name did.
Curated matrix for GPT-6 Sol vs GPT-5.6 Sol — confirm live limits and pricing on each vendor’s official pages.
How they compare
Criterion-by-criterion notes from the catalog—not a ranking. Validate on your own gold set.
| Criterion | GPT-6 Sol | GPT-5.6 Sol |
|---|---|---|
| Best for | New Sol-tier coding and agent routes. | Pinned gpt-5.6-sol deployments and the prior Sol default. |
| Access and platforms | gpt-6-sol in the API and in ChatGPT Work and Codex for paid plans. | gpt-5.6-sol remains in the catalog and is marked superseded by GPT-6 Sol. |
| Context window | 1,050,000 / 128K. Knowledge cutoff April 20, 2026. Long-context multipliers above 272K. | Use the live GPT-5.6 Sol card for context. Do not copy GPT-6 Sol's 1.05M figure onto it. |
| Input and output | Text and image in; text out. | Text and image in; text out. |
| Reasoning control | none through max, default medium. | GPT-5.6 effort controls. Re-check the card rather than assuming the GPT-6 ladder. |
| Coding and agents | OpenAI describes it as built for complex coding and agentic workflows, carrying forward Astra-era product surfaces at a lower price. | The previous Sol flagship lane, including Daybreak-era defensive workflows documented on that model. |
| Cost posture | $2 / $0.20 cached / $2.50 cache write / $10 output per 1M at standard rates. | Pricing page: short context $4 input / $0.40 cached / $5 cache write / $20 output; long context $8 / $0.80 / $10 / $30 per 1M. |
| Operational risk | New ID. Replay pinned GPT-5.6 Sol evals before you cut over. | Staying pinned avoids a migration and forgoes the lower GPT-6 list price. |
Key insights
Concrete technical or product signals.
- Short-context list price on the pricing page is half for GPT-6 Sol ($2/$10 versus $4/$20). That matches OpenAI's '50% below GPT-5.6 promotional pricing' line for the sticker, not for every long-context or fast-mode bill.
- GPT-6 Sol's 272K multiplier is documented on its model card. Do not assume GPT-5.6 Sol uses that same breakpoint without checking its card.
- No quality delta is published here, so none is stated.
Use cases
Where this shines in production.
- Migrating gpt-5.6-sol
- Repricing a Sol-tier agent
- Deciding whether a pin can stay
Limitations & trade-offs
What to watch for.
- Not Sol vs Luna and not Sol vs Astra.
- Promotional prices can differ from the pricing-page list.
- Daybreak or other product entitlements on GPT-5.6 Sol are not automatically on GPT-6 Sol.
Watch-outs
Who should pass, and what to validate before rollout.
- Do not migrate every pinned call on announcement day.
- Do not treat the 50% slogan as the long-context bill.
- Do not stop at Sol if the task still needs Astra.
Final recommendation
What to do after reading the table.
Use GPT-6 Sol for new Sol-tier work and keep GPT-5.6 Sol only for pins that have not been replayed.
FAQ
Is GPT-6 Sol better than GPT-5.6 Sol?
Use GPT-6 Sol for new Sol-tier work and keep GPT-5.6 Sol only for pins that have not been replayed.
Which is better for coding: GPT-6 Sol or GPT-5.6 Sol?
GPT-6 Sol: OpenAI describes it as built for complex coding and agentic workflows, carrying forward Astra-era product surfaces at a lower price. GPT-5.6 Sol: The previous Sol flagship lane, including Daybreak-era defensive workflows documented on that model. The catalog does not declare a winner on coding and agents.
Which is cheaper: GPT-6 Sol or GPT-5.6 Sol?
Listed unit prices: GPT-6 Sol $2 / $0.20 cached / $2.50 cache write / $10 output per 1M at standard rates; GPT-5.6 Sol Pricing page: short context $4 input / $0.40 cached / $5 cache write / $20 output; long context $8 / $0.80 / $10 / $30 per 1M. A lower listed unit price is not the same as a lower total workload cost—tokens, session minutes, caching, introductory rates, and add-on modes can reverse the ranking. Confirm live rates on each vendor’s official page.
Can I use both GPT-6 Sol and GPT-5.6 Sol?
Yes. Many teams keep both and route by constraint. Use GPT-6 Sol for New Sol-tier coding and agent routes, and GPT-5.6 Sol for Pinned gpt-5.6-sol deployments and the prior Sol default. Confirm vendor terms before mixing them in one production workflow.