Model comparison - Similar price, same tier
GPT-6 Luna vs Mistral Small 4
GPT-6 Luna is from OpenAI and Mistral Small 4 is from Mistral AI. On list price, GPT-6 Luna charges 33% less than Mistral Small 4 for input ($0.10 vs $0.15 per 1M tokens), and GPT-6 Luna charges 17% less than Mistral Small 4 for output ($0.50 vs $0.60 per 1M tokens). GPT-6 Luna has a 1,050,000-token context window and Mistral Small 4 256,000 tokens; GPT-6 Luna returns up to 128,000 output tokens per response, and no primary source states a max output for Mistral Small 4. GPT-6 Luna was released on September 22, 2026 and Mistral Small 4 on March 15, 2026. Mistral Small 4 publishes open weights (Apache 2.0); GPT-6 Luna is closed-weights.
Last verified from each provider's pricing page. All sources
Side-by-side specs
| Spec | GPT-6 Luna | Mistral Small 4 |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Input / 1M tokens | $0.10 | $0.15 |
| Output / 1M tokens | $0.50 | $0.60 |
| Cache read / 1M | $0.01 | $0.015 |
| Cache write / 1M | $0.125 | - |
| Batch input / 1M | $0.05 | $0.075 |
| Batch output / 1M | $0.25 | $0.30 |
| Long-context rates above | 272,000 tokens | - |
| Context window | 1,050,000 | 256,000 |
| Max output | 128,000 | - |
| Release date | ||
| Weights | Closed | Open |
| License | - | Apache 2.0 |
| API model id | gpt-6-luna | mistral-small-2603 |
| AI Gateway id | openai/gpt-6-luna | mistral/mistral-small |
| Last verified |
Prices in USD per 1M tokens at each provider's standard first-party rate. A dash means the provider does not bill that item separately or no primary page states it.
What each costs in practice
The same three workloads every model page uses, worked from each model's standard list rates. Swap in your own token counts with the math on each model's page.
| Workload | GPT-6 Luna | Mistral Small 4 |
|---|---|---|
| One agent session1M input tokens and 100K output tokens, no caching. | $0.15 | $0.21 |
| A chat app10,000 requests a day at 2K input and 500 output tokens each. | $4.50$135.00 per 30-day month | $6.00$180.00 per 30-day month |
| The same session at a 90% cache hit90% of the input is read from the prompt cache. The one-time cache write premium is not included. | $0.069 | $0.0885 |
Show the math
GPT-6 Luna
- One agent sessionInput: 1M x $0.10 = $0.10Output: 0.1M x $0.50 = $0.05
- A chat appInput: 20M x $0.10 = $2.00Output: 5M x $0.50 = $2.50
- The same session at a 90% cache hitCached input: 0.9M x $0.01 = $0.009Uncached input: 0.1M x $0.10 = $0.01Output: 0.1M x $0.50 = $0.05
Mistral Small 4
- One agent sessionInput: 1M x $0.15 = $0.15Output: 0.1M x $0.60 = $0.06
- A chat appInput: 20M x $0.15 = $3.00Output: 5M x $0.60 = $3.00
- The same session at a 90% cache hitCached input: 0.9M x $0.015 = $0.0135Uncached input: 0.1M x $0.15 = $0.015Output: 0.1M x $0.60 = $0.06
Benchmarks under the same setting
No board in the benchmark directory lists both GPT-6 Luna and Mistral Small 4 under the same setting, so there is no like-for-like score to show here.
Set them up in your tools
Step-by-step guides whose official docs list GPT-6 Luna or Mistral Small 4 by model id.
- Use Mistral in AiderLists Mistral Small 4
- Use Mistral in ClineLists Mistral Small 4
- Use Mistral in ContinueLists Mistral Small 4
- Use Mistral in GitHub CopilotLists Mistral Small 4
- Use Mistral in GooseLists Mistral Small 4
- Use Mistral in Kilo CodeLists Mistral Small 4
- Use Mistral in OpenCodeLists Mistral Small 4
- Use Mistral in Roo CodeLists Mistral Small 4
- Use Mistral in ZedLists Mistral Small 4
- Use OpenAI in AiderLists GPT-6 Luna
- Use OpenAI in ClineLists GPT-6 Luna
- Use OpenAI in Codex CLILists GPT-6 Luna
- Use OpenAI in ContinueLists GPT-6 Luna
- Use OpenAI in GooseLists GPT-6 Luna
- Use OpenAI in OpenCodeLists GPT-6 Luna
- Use OpenAI in Roo CodeLists GPT-6 Luna
- Use OpenAI in ZedLists GPT-6 Luna
Model pages
FAQ
How do GPT-6 Luna and Mistral Small 4 compare on price?
On list price, GPT-6 Luna charges 33% less than Mistral Small 4 for input ($0.10 vs $0.15 per 1M tokens), and GPT-6 Luna charges 17% less than Mistral Small 4 for output ($0.50 vs $0.60 per 1M tokens). For one agent session of 1M input and 100K output tokens with no caching, that is $0.15 on GPT-6 Luna and $0.21 on Mistral Small 4. Prices are each provider's first-party list rates, verified October 17, 2026 and October 17, 2026.
What are the context windows of GPT-6 Luna and Mistral Small 4?
GPT-6 Luna has a 1,050,000-token context window and Mistral Small 4 256,000 tokens; GPT-6 Luna returns up to 128,000 output tokens per response, and no primary source states a max output for Mistral Small 4.
Are GPT-6 Luna and Mistral Small 4 open weights?
GPT-6 Luna is closed-weights and is called through OpenAI's API as gpt-6-luna. Mistral Small 4's weights are published at huggingface.co under the Apache 2.0.
More comparisons
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- Claude Haiku 5.5 vs Mistral Small 4Similar price, same tier
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- GLM-5.3-Flash vs GPT-6 LunaSimilar price, same tier
- DeepSeek V4.1 Flash vs Mistral Small 4Similar price, same tier
- GPT-6 Luna vs Qwen3.8-FlashSimilar price, same tier
- GLM-5.3-Flash vs Mistral Small 4Similar price, same tier
- GPT-5.6 Luna vs GPT-6 LunaSame provider, successor
Sources
GPT-6 Luna verified from developers.openai.com; Mistral Small 4 verified from docs.mistral.ai. This page is as current as the older of the two: .
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