OpenAI launches GPT-6 Sol and Luna, saying Sol makes about half as many mistakes as GPT-5.6 Sol and Luna matches GPT-5.6 Sol's performance at ~1% of the cost

GPT-6 Sol and Luna arrive less than three months after GPT-5.6, with OpenAI claiming major accuracy gains, dramatic cost reductions …

ZDNET 2026-09-22 David Gewirtz

Context & Ripple Effects

OpenAI had already made serving efficiency a commercial lever: in July it cut GPT-5.6 Luna pricing by about 80% after improving the systems that served it. GPT-5.6 Sol had also been positioned for demanding workflows, including an Ultra mode with subagents.

Sol and Luna extend that cadence from price reductions within an existing generation to a new two-tier offering. The accompanying published API pricing makes the comparison operational for developers choosing between capability and volume.

First-order effects

OpenAI API customers can use Luna for workloads where its claimed GPT-5.6 Sol-level performance is sufficient, with OpenAI claiming roughly a 99% lower cost for that comparison.
Teams using Sol gain a higher-accuracy option, as OpenAI claims GPT-6 Sol makes about half as many mistakes as GPT-5.6 Sol.

Second-order effects

GPT-5.6 users must re-evaluate model routing: Luna creates a lower-cost default tier while Sol becomes the option for tasks where error reduction justifies greater spend.
OpenAI’s own API pricing becomes more explicitly tied to outcome and workload tiering, rather than treating token price alone as the product comparison.

Third-order effects

If OpenAI’s performance and cost claims hold in production, model vendors will face pressure to compete on cost per useful task—combining accuracy, retries, and inference price—rather than headline token rates.
Rapid efficiency-driven repricing favors applications that can route work across model tiers, making inference economics a more central product-design constraint.

The trend: Foundation-model competition is shifting toward tiered offerings that pair stronger task performance with sharply lower inference costs.

Discussion

@sama Sam Altman on x
We want the OpenAI API to feature the best model at every price point and to be the best at every modality (text, code, image, video, etc). And then we want you all to come up with great ideas and build them and to get to be happy users. The best ideas will come from you all.
@sama Sam Altman on x
Especially compared by per-task pricing, which is the metric that should matter, I don't think there is anything competitive anywhere in the market. We want people to be able to use tons of AI; it is important to being able to explore this new renaissance in front of us.
@sama Sam Altman on x
GPT-6 Sol and Luna are great models but also these characters are so cute
@thsottiaux Tibo on x
GPT-6 Sol and Luna are out. Not only are they a very significant improvement across the board, but also in writing and general “you know when you try it
@ricmac Richard MacManus on x
Isn't competition great!! Who was that VC who said monopolies are best? (Thiel). Certainly not for us users.
@openaidevs @openaidevs on x
GPT-6 Sol and Luna just landed in Astra's orbit. Both launch today with API prices 50% lower than GPT-5.6. Build with Sol. Scale with Luna. To production and beyond.
@openai @openai on x
Please welcome GPT-6 Sol and GPT-6 Luna to the GPT-6 universe. GPT-6 Sol and Luna build on the advances behind GPT-6 Astra, bringing much of its strengths into faster and more affordable models to support work at scale. We've also made caching and inference more efficient, and we…
@cheatyyyy @cheatyyyy on x
GPT-6 Sol and Luna benchmarks from the official blogpost!
@dandr1s Dan on x
🚨 GPT-6 Sol is HALF the price of GPT-5.6 Sol. Standard API pricing per 1M tokens (input / output): Sol: $4 / $20 → $2 / $10 Luna: $0.20 / $1.20 → $0.10 / $0.50 That's 50% cheaper input and nearly 60% cheaper output for Luna.
@cheatyyyy @cheatyyyy on x
GPT-6 Luna and Sol live on the API! GPT-6 Luna: Input: $0.10 / MTok Output: $0.50 / MTok Cache Write: $0.125 / MTok Cache Read: $0.01 / MTok GPT-6 Sol: Input: $2.00 / MTok Output: $10.00 / MTok Cache Write: $2.50 / MTok Cache Read: $0.20 / MTok
@angaisb_ Angel on x
GPT-6 Sol and Luna API pricing is out They're so cheap! - Sol: $2 input / $10 output, down from $4 / $20 for 5.6 Sol - Luna: $0.10 input / $0.50 output, down from $0.20 / $1.20 for 5.6 Luna Per 1M tokens, short context, excluding 5.6 Sol's promotional pricing
@scaling01 @scaling01 on x
GPT-6 Sol and Luna are dirt cheap GPT-6 Sol is half the price of Opus 5.5
@andrewcurran_ Andrew Curran on x
It's a double release day just like old times! GPT-6 Sol and GPT-6 Luna are rolling out, for some of my mutuals they are already live. OpenAI announcement incoming.
@kimmonismus @kimmonismus on x
Here we go: next big launch incoming! Sol and Luna rolling out. I'll post the benchmarks as soon as I get access to them! Check your codex friends!
@imsh4yy Shayan on x
Fable, Opus, Sonnet, Haiku. Astra, Sol, Terra (RIP), Luna. This is the most straightforward it's ever been.
r/OpenaiCodex r on reddit
Introducing GPT-6 Sol and Luna
@levie Aaron Levie on x
What an insane day in AI. The frontier models just became substantially cheaper, with the Opus 5.5 price cuts, and now with GPT-6 Sol and Luna dropping token prices by 50%. The rate at which the cost per task (on a like-for-like basis) drops in AI is unlike any other type of tech…
@synthwavedd Leo on x
It seems OpenAI are making up for 6 Sol likely not being as good as Opus 5.5 through its pricing. Still waiting for benchmarks to drop, but... GPT-6 Sol is 50% of the price of 5.6 Sol. $2 in per million tokens, $10 out. 🤑
@polynoamial Noam Brown on x
GPT-6 Sol and Luna are out, and they are better AND 50% cheaper than 5.6. Luna is now $0.10 input / $0.50 output per 1M tokens. This is on top of the 80% price cut to Luna we made at the end of July. Output went from $6 -> $0.50 within two months.
@reach_vb @reach_vb on x
We are loading a BANKED RESET into all accounts of our Plus, Pro and Business users!!
@scaling01 @scaling01 on x
lmao what is this? now we know why they are so cheap
@artificialanlys @artificialanlys on x
GPT-6 Sol and Luna push the cost efficiency frontier by halving cost relative to GPT-5.6 Sol and Luna. Intelligence Index and Coding Agent Index scores remain level with GPT-5.6, with progress in some evaluations and regressions in others Pricing is approximately half that of GPT…
@kimmonismus @kimmonismus on x
Benchmarks GPT-6 Sol & Luna: • FrontierCode: 48.4% vs. Fable 5.1's 48.7%, both at xhigh. $1.37 vs. $9.27 per task, roughly 85% cheaper. • DeepSWE: 68.8% at max vs. Fable 5's best result of 69.9% at xhigh. $2.74 vs. $13.41 per task, roughly 80% cheaper. • AutomationBench: 33.2% at…
@reach_vb @reach_vb on x
Introducing GPT-6 Sol and Luna, bringing the advances behind Astra to faster, more affordable models. ✨ 💻 Stronger coding and computer use 🎯 Improved factuality and alignment 💬 Clearer answers with less jargon > On AutomationBench, Sol at xhigh effort outperforms Claude Opus 5 at…
@openai @openai on x
GPT-6 Sol and Luna build on Astra's advances in alignment, showing improvements over their GPT-5.6 counterparts.
@zeeg David Cramer on x
Luna continues to be my favorite model in the market Tolerable price point (I'd still love to see this much cheaper), great capabilities, acceptable speed. Its a good balance across all aspects given whats available today.
Julien Simiand Julien Simiand on linkedin
I've been telling my customers that prices keep coming down, release after release, while we keep pushing to get more useful work out of every token. …

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