OpenAI · Simple tasks at low cost
GPT-6 Luna
A cost-effective option for clearly defined, repetitive tasks.
- Costs
- $0.10 input / $0.50 output per million tokens. Above 272 thousand input tokens: 2× input and 1.5× output.
- Speed
- We have not independently measured speed on a comparable basis.
- Availability
- OpenAI API
- Input length
- 1,050,000 tokens in total; output capped at 128 thousand tokens.
- Inputs
- Text and images → text
Data checked . Published September 22, 2026. Specifications and prices are provided by the vendor; usage recommendations come from the editorial team. We do not yet have our own comparative test of this version.
Ideal use
When to choose it
- Text classification and brief summaries
- Processing a large number of simple requests
Usage boundaries
When to choose another model
- For complex tasks, check whether the low price leads to more corrections.
Traceable supporting sources
Data and measurement sources
Distinguish between the manufacturer's documentation and the results of a specific test. Measurements also depend on the settings and the task set used.
Vendor documentation
Specifications, availability, and termsManufacturer data verified as of the review date. Recommended use is an editorial interpretation.
Open original source ↗Efficiency in practice
With what GPT-6 Luna combine
Many tasks without unnecessary costs
A low-cost model handles routine work, and the more expensive one gets only the truly difficult cases.
Use your own data to verify when a stronger model should take over the work. A model cannot reliably assess its own answer.Trends over time
Related events from AI Radar
OpenAI makes GPT-6 Sol and GPT-6 Luna available on the Amazon Bedrock platform
Developers working with the Amazon Bedrock platform gain another model choice based on the task type: assign more demanding tasks to GPT-6 Sol and simple, frequent tasks to GPT-6 Luna, and adjust the reasoning effort level as needed.
Companies running AI tasks on the Amazon Bedrock platform can deploy newer models from OpenAI at a lower price than GPT-5.6, with enterprise security controls (IAM, CloudTrail, VPC PrivateLink) and a choice between a model for complex tasks and a model for high volumes of simple requests.
OpenAI fixed a bug in image encoding in the GPT-6 Sol and GPT-6 Luna models
Developers who used image inputs with the GPT-6 Sol or GPT-6 Luna models may have encountered worse results due to a bug in image encoding; after the fix, it is advisable to retest your tasks involving visual content.
Companies running pipelines with image inputs via the GPT-6 Sol or GPT-6 Luna models (API, Codex, computer use) may have received worse results on visual tasks due to a bug; it is now advisable to re-verify output quality and, if needed, recompute the affected workflows.
OpenAI halved prices for the GPT-6 Sol and Luna models; independent analysis does not confirm a performance improvement
New: Anthropic released Claude Opus 5.5 on the same day (2026-09-23), roughly an hour after OpenAI; Claude Opus 5.5 is 20% cheaper than the previous Opus 5.0 ($4/$20 vs $5/$25); Opus 5.5 improved communication style and token efficiency; The model releases launch a 'price war' between the two largest AI companies; GPT-6 Luna and Sol are part of a broader strategy of price competition, not an isolated release
Developers working with the API from OpenAI can reduce inference costs by up to half while maintaining the same usage pattern (Sol for more complex tasks, Luna for high-volume simple tasks), but independent tests suggest that a lower price may not mean higher or even the same output quality in all cases.
Businesses gain a cheaper option for reasoning models for high-volume or repetitive tasks (summaries, data extraction, code), but according to an independent analysis, actual output quality has not improved compared with the previous generation and has instead declined on some knowledge work tasks, so deployment decisions should not rely solely on the manufacturer's claims about price/performance.
OpenAI opens the Pro plan to new users, but halves API credits and moves toward payment for actual usage
New: API credits per dollar halved; Pro plan at $200/month reopened to new users; 5-hour window for the weekly allotment removed; Strategic shift from subsidized subscription models to pay-per-use pricing; Microsoft is making similar changes with Copilot
Users considering the OpenAI Pro plan at $200/month now also benefit from the removal of the 5-hour limit, but those paying through the API receive fewer credits for the same dollar than before — the new lower prices of the GPT-6 Sol and Luna models only partially offset this.
Companies using the OpenAI API should recalculate their AI operating costs, because the number of credits per dollar is changing and the price of the new GPT-6 Sol and Luna models has also fallen by 50 % compared with the 5.6 series — the net impact on the budget depends on the specific usage volume and types of models used.
Next step
Compare the model using your actual task.
A benchmark narrows the selection. A short trial on your data determines the choice.