Comparison · Mistral and OpenAI
Mistral Small 4 vs GPT-5.4 Nano
Listed API prices of Mistral Small 4 and GPT-5.4 Nano turned into the cost of the same three standard tasks and what each provider’s API documentation says about features that break on a switch. Output quality, speed and answer length are not compared.
Calculated impact cost per task and per month
For an L2 task (deep analysis over a 50,000-token document, 3 steps), Mistral Small 4 costs $0.026 and GPT-5.4 Nano $0.036 at the prices listed in the United States on , so Mistral Small 4 is 27.8 % less than GPT-5.4 Nano, counting visible output only, without cache discounts or hidden reasoning.
| Task | Mistral Small 4, per task | GPT-5.4 Nano, per task | Mistral Small 4, per month | GPT-5.4 Nano, per month | Mistral Small 4 vs GPT-5.4 Nano, per task |
|---|---|---|---|---|---|
| L1Micro-task (classification or strict JSON extraction) | $0.0003per L1 task | $0.0006per L1 task | $5.04per month | $8.03per month | −37.3 % |
| L2Deep analysis over a 50,000-token document | $0.026per L2 task | $0.036per L2 task | $374.49per month | $519.03per month | −27.8 % |
| L3Agentic coding loop, 15 steps | $0.203per L3 task | $0.274per L3 task | $2,959.78per month | $4,005.51per month | −26.1 % |
Calculated Per month: 20 tasks an hour around the clock, 730 hours.
Prices USD per 1M tokens
| Price | Mistral Small 4 | GPT-5.4 Nano |
|---|---|---|
| Input, per 1M tokens | $0.150 | $0.200 |
| Output, per 1M tokens | $0.600 | $1.25 |
| Price from | OpenRouter · source page (data) Published | OpenRouter · source page (data) Published |
| Read | · the United States | · the United States |
| Context window | 262,144 tokens | 400,000 tokens |
What can I use it for? six common tasks, our data checks
Quality on your task: not measured by Measured Lab yet.
| Task | Mistral Small 4 | GPT-5.4 Nano |
|---|---|---|
| Answer customer messages | Fits on price and context | — |
| Pull data from invoices and documents with strict JSON and page images | Fits on price and context | — |
| Summarize documents and meetings | Fits on price and context | — |
| Translate content | Fits on price and context | — |
| Chat assistant on your website | Fits on price and context | — |
| Write and review code with tool calls | Fits on price and context | — |
| Tasks it fits | 6 of 6 | — |
Checks of our data for six common tasks: a published price, a context window and answer length for the task and, where the task needs them, strict JSON output, page images and tool calls; prices, cost a month and terms for each model on its model card. GPT-5.4 Nano is not in the model picker. Compare models for your own task in the model picker.
What breaks when you switch Published provider documentation
Moving from Mistral to OpenAI: every feature that Mistral’s documentation lists as supported is also listed as supported by OpenAI.
Moving from OpenAI to Mistral, 3 of the 5 features may not carry over, by each provider’s documentation:
- Streamed tool arguments — OpenAI: yes; Mistral: not stated. An interface that shows arguments as they are written sees nothing until the whole call is ready.
- Reasoning with tools — OpenAI: yes; Mistral: not stated. Switching reasoning on can rule out some tool settings or output formats, or the other way round.
- Cache covers tool definitions — OpenAI: yes; Mistral: not stated. Where the cache does not cover tool definitions, a long tool list is paid as fresh input on every request.
| Feature of the API | Mistral | OpenAI |
|---|---|---|
| Strict JSON schemas | Yes | Yes |
| Parallel tool calls | Yes | Yes |
| Streamed tool arguments | Not stated | Yes |
| Reasoning with tools | Not stated | Yes |
| Cache covers tool definitions | Not stated | Yes |
What each provider’s own API documentation says, read ; “not stated” is not the same as “no”. Quotes and sources: what breaks when you switch AI APIs.