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GPT-5.6 Luna vs Mistral Small 4

Compact price-performance from OpenAI and Mistral.

Figures as of , read live from the model registry Zeplik bills against.

What the numbers say

Derived from the live registry Zeplik routes and bills against. Credits: 1 credit = $0.10, computed from the raw provider rate with a 1.20x margin.

Side by side

GPT-5.6 Luna

OpenAI

GPT-5.6 Luna is a fast, cost-efficient model in OpenAI's GPT-5.6 series.

Provider
OpenAI
Context window
1.1M tokens
Input price
2.4 credits / 1M tokens ($0.20 raw)
Output price
14.4 credits / 1M tokens ($1.20 raw)
Vision (image input)
Yes
Tool calling
Yes
Extended reasoning
No

Best for

  • Balanced everyday work: writing, questions, brainstorming and summarization
  • Very long documents and codebases: a 1.1M-token window fits entire books or repositories in one conversation
  • Working with images: screenshots, charts, photos and scanned documents alongside text
  • Tool use and agents: reliably calls functions, so it can search, run skills and drive workflows

Mistral Small 4

Mistral

Mistral Small 4 is the next major release in the Mistral Small family, unifying the capabilities of several flagship Mistral models into a single system.

Provider
Mistral
Context window
262K tokens
Input price
1.8 credits / 1M tokens ($0.15 raw)
Output price
7.2 credits / 1M tokens ($0.60 raw)
Vision (image input)
Yes
Tool calling
Yes
Extended reasoning
No

Best for

  • High-volume everyday tasks where speed and cost matter: summaries, drafts, quick questions
  • Long documents: the 262K-token window holds lengthy reports, contracts or papers whole
  • Working with images: screenshots, charts, photos and scanned documents alongside text
  • Tool use and agents: reliably calls functions, so it can search, run skills and drive workflows

Try both on Zeplik

The honest answer to most model debates is to run your own prompt on both. Zeplik puts GPT-5.6 Luna and Mistral Small 4 in the same chat, so you can switch mid-conversation and compare answers on the work you actually do.

Pick a model and ask. Your prompt opens in the Zeplik app with that model selected.

Model to ask

Frequently asked questions

What is the difference between GPT-5.6 Luna and Mistral Small 4?
Mistral Small 4 is about 2.0x cheaper on output tokens (7.2 vs 14.4 credits per 1M). GPT-5.6 Luna takes noticeably more context: 1.1M vs 262K tokens. GPT-5.6 Luna is the newer release (July 2026 vs March 2026).
Is GPT-5.6 Luna or Mistral Small 4 cheaper?
Mistral Small 4 is cheaper: 7.2 credits per million output tokens against 14.4. 1 credit = $0.10, computed from the raw provider rate with a 1.20x margin.
Which has the larger context window, GPT-5.6 Luna or Mistral Small 4?
GPT-5.6 Luna, at 1.1M tokens against 262K.
Can I use both GPT-5.6 Luna and Mistral Small 4 on Zeplik?
Yes. Zeplik is a multi-model chat, so both sit behind one account and you can switch between them mid-conversation to compare answers on your own prompt.
Do GPT-5.6 Luna and Mistral Small 4 need a paid plan?
One of the two is open to free accounts; the other needs a paid plan (Plus or above).

Related comparisons

GPT-5.6 Luna detailsMistral Small 4 detailsAll comparisons

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