Which is cheaper, Kimi K3.1 Pro and GPT-6 Luna?

GPT-6 Luna has the lowest input price. Per 1M input tokens: Kimi K3.1 Pro from $2.00 and GPT-6 Luna from $0.10.

Which has the larger context window, Kimi K3.1 Pro and GPT-6 Luna?

Kimi K3.1 Pro has the largest context window: Kimi K3.1 Pro 1,048,576 tokens and GPT-6 Luna 400,000 tokens.

Which is smarter, Kimi K3.1 Pro and GPT-6 Luna?

Kimi K3.1 Pro scores highest on the Artificial Analysis Intelligence Index: Kimi K3.1 Pro 46.0 and GPT-6 Luna 27.8.

Can I switch between Kimi K3.1 Pro and GPT-6 Luna 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 (moonshotai/kimi-k3.1-pro, openai/gpt-6-luna).

Kimi K3.1 Pro vs GPT-6 Luna

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

Estimate monthly cost for these models

Kimi K3.1 Pro MoonshotAImoonshotai/kimi-k3.1-pro

GPT-6 Luna OpenAIopenai/gpt-6-luna

Creator

MoonshotAI

OpenAI

Released

Oct 23, 2026

Sep 22, 2026

Context window

1.05M

400K

Max output

1.05M

128K

Input / 1MLowest provider price

$2.00

$0.10

Output / 1MLowest provider price

$10.00

$0.50

Providers

IntelligenceArtificial Analysis index

46.0

27.8

Accepts

Text, Image

Files, Image, Text

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Kimi K3.1 Pro vs GPT-6 Luna: summary

Kimi K3.1 Pro and GPT-6 Luna are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Kimi K3.1 Pro, from MoonshotAI, has a 1,048,576-token context window, costs $2.00/1M input and $10.00/1M output tokens and scores 46.0 on the Artificial Analysis Intelligence Index.

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 27.8 on the Artificial Analysis Intelligence Index.

GPT-6 Luna is the cheapest on input, 20× cheaper than the next model, Kimi K3.1 Pro has the largest context window and Kimi K3.1 Pro 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="moonshotai/kimi-k3.1-pro", messages=[...]) # or client.chat.completions.create(model="openai/gpt-6-luna", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis