Which is cheaper, GPT-6 Luna and GPT-6 Sol?

GPT-6 Luna has the lowest input price. Per 1M input tokens: GPT-6 Luna from $0.10 and GPT-6 Sol from $2.00.

Can I switch between GPT-6 Luna and GPT-6 Sol without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (openai/gpt-6-luna, openai/gpt-6-sol).

GPT-6 Luna vs GPT-6 Sol

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

GPT-6 Luna OpenAIopenai/gpt-6-luna

GPT-6 Sol OpenAIopenai/gpt-6-sol

Creator

OpenAI

Released

Sep 22, 2026

Context window

400K

Max output

128K

Input / 1MLowest provider price

$0.10

$2.00

Output / 1MLowest provider price

$0.50

$10.00

Providers

IntelligenceArtificial Analysis index

38.1

47.6

Accepts

Files, Image, Text

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

GPT-6 Luna vs GPT-6 Sol: summary

GPT-6 Luna and GPT-6 Sol are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

GPT-6 Luna, from OpenAI, has a 400,000-token context window, costs $0.10/1M input and $0.50/1M output tokens and scores 38.1 on the Artificial Analysis Intelligence Index.

GPT-6 Sol, from OpenAI, has a 400,000-token context window, costs $2.00/1M input and $10.00/1M output tokens and scores 47.6 on the Artificial Analysis Intelligence Index.

GPT-6 Luna is the cheapest on input, 20× cheaper than the next model and GPT-6 Sol scores highest for intelligence.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="openai/gpt-6-luna", messages=[...]) # or client.chat.completions.create(model="openai/gpt-6-sol", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis