Home / Compare / Mistral Small 4 vs GPT-5.6 Luna

Mistral Small 4 vs GPT-5.6 Luna

For a typical chat reply (2,000 tokens in, 400 out), GPT-5.6 Luna costs 1.6× as much as Mistral Small 4: $0.88 against $0.54 per 1,000 requests at list price on 2026-09-28.

Mistral Small 4GPT-5.6 Luna
Input, per 1M tokens$0.15$0.20
Output, per 1M tokens$0.60$1.20
Context window262K1.05M
Classification or routing (600 tokens in, 10 out), per 1,000$0.096$0.132
Chat reply (2,000 in, 400 out), per 1,000$0.54$0.88
Retrieval-augmented answer (8,000 in, 500 out), per 1,000$1.50$2.20
Confidence signalnono
Tool callingyesyes

Which one should carry your traffic?

If Mistral Small 4 answers your requests as well as GPT-5.6 Luna, moving that traffic saves 39% on chat-shaped requests. Averages cannot tell you whether it does for your requests. Mistral Small 4 does not expose a confidence signal through OpenRouter, so Gimbix would test it as a full replacement rather than a first answer.

Mistral Small 4 profile · GPT-5.6 Luna profile · Measure it on your traffic