Maximize capability.
For the hardest end-to-end work: complex reasoning, coding, computer use, research and document creation.
$10 input · $50 outputGPT-6 Astra reference ↗MODEL COMPARISON / VERIFIED 2026-09-26
GPT-6 Astra
vs Sol vs Luna.
A decision-oriented comparison built from OpenAI’s official model cards and API pricing. Same 1.05M context window. Very different capability positioning and unit economics.
Balance capability and cost.
Built for complex coding and agentic workflows, at one-fifth of Astra’s listed short-context token rates.
$2 input · $10 outputGPT-6 Sol reference ↗Optimize for volume.
OpenAI’s most efficient GPT-6 option for focused, high-volume tasks and cost-sensitive workloads.
$0.10 input · $0.50 outputGPT-6 Luna reference ↗SPECIFICATIONS
Side-by-side.
| Model | Positioning | Best fit | Context | Max output | Input | Cached | Output |
|---|---|---|---|---|---|---|---|
| GPT-6 Astragpt-6-astra | Highest capability | Complex reasoning, coding, computer use, research and document creation | 1,050,000 | 128,000 | $10.00 | $1.00 | $50.00 |
| GPT-6 Solgpt-6-sol | Capability / cost balance | Complex coding and agentic workflows | 1,050,000 | 128,000 | $2.00 | $0.20 | $10.00 |
| GPT-6 Lunagpt-6-luna | Efficiency | Focused, high-volume and cost-sensitive workloads | 1,050,000 | 128,000 | $0.10 | $0.01 | $0.50 |
Listed rates are the official short-context token prices shown on OpenAI’s model cards. Prompts above 272K input tokens use 2x input/cache rates and 1.5x output rates for the full request.
COST EXAMPLES
What the price gap means.
One short-context workload
GPT-6 Astra$1.5100K input + 10K output
GPT-6 Sol$0.3100K input + 10K output
GPT-6 Luna$0.015100K input + 10K output
Monthly volume
GPT-6 Astra$15010M input + 1M output
GPT-6 Sol$3010M input + 1M output
GPT-6 Luna$1.510M input + 1M output
Monthly example assumes requests remain at or below 272K input tokens each. Tool calls, regional processing and other service tiers can change total cost.
WHAT STAYS THE SAME
Context is not the differentiator.
All three official model cards list a 1,050,000-token context window and 128,000 maximum output tokens. The choice is driven more by capability needs, workload type and cost.
PRICE RATIO
100× from Luna to Astra.
At the listed short-context rates, Astra’s input and output token prices are 100× Luna’s. Sol sits at 20× Luna and one-fifth of Astra.
OFFICIAL SOURCES
GPT-6 Astra model card↗GPT-6 Sol model card↗GPT-6 Luna model card↗OpenAI API pricing↗QUICK ANSWERS
What is the difference between GPT-6 Astra, Sol and Luna?
OpenAI positions Astra as its most capable model for the hardest end-to-end work, Sol for complex coding and agentic workflows, and Luna as its most efficient option for focused high-volume tasks.
Do GPT-6 Astra, Sol and Luna have the same context window?
Yes. OpenAI lists a 1,050,000-token context window and a 128,000-token maximum output for all three models.
Which GPT-6 model is cheapest?
GPT-6 Luna has the lowest listed token prices: $0.10 per 1M input tokens, $0.01 cached input and $0.50 output at the listed short-context rates.
When does GPT-6 long-context pricing apply?
OpenAI states that prompts above 272K input tokens use higher rates for the full request: 2x input and cache rates and 1.5x output rates.