Choose Inception: Mercury 2.5 Preview if…
- cost matters at scale — it is 74% cheaper on a typical 3:1 input/output mix ($6.00 vs $23.25 a month for 50,000 support chats)
- you want the newer model — released 2026-08-31, 6 months after the other
Inception: Mercury 2.5 Preview vs Mistral: Mistral Small 4
Neither wins outright: Inception: Mercury 2.5 Preview is the pick when cost matters at scale, Mistral: Mistral Small 4 when you need image input.
Key numbers
| Spec | Inception: Mercury 2.5 Preview | Mistral: Mistral Small 4 |
|---|---|---|
| Provider | Inception | Mistral AI |
| Input price (per 1M tokens) | $0.04 | $0.15 |
| Output price (per 1M tokens) | $0.15 | $0.60 |
| Blended price (3:1 input/output) | $0.07 | $0.26 |
| Cheaper than … of all models we track | 85% | 64% |
| Context window | 260K tokens (~390 pages) | 262K tokens (~393 pages) |
| Larger context than … of all models | 47% | 48% |
| Max output per response | 66K tokens (~49,200 words) | 210K tokens (~157,300 words) |
| Input types | text | text, image |
| Output types | text | text |
| Free variant | No | No |
| Listed since | 2026-08-31 | 2026-03-16 |
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What it costs for real workloads
Monthly cost at list price for five common workloads. Token counts per unit are stated so you can scale them to your own traffic. A workload that does not fit a model's context window is marked rather than priced.
| Workload (per month) | Inception: Mercury 2.5 Preview | Mistral: Mistral Small 4 | Difference |
|---|---|---|---|
| Customer-support chatbot 50,000 conversations — each a 6-turn conversation (1,500 in / 400 out tokens) | $6.00 | $23.25 | Inception: Mercury 2.5 Preview saves $17.25 |
| RAG search over documents 20,000 questions — each a question answered from ~8 retrieved passages (6,000 in / 500 out tokens) | $6.30 | $24.00 | Inception: Mercury 2.5 Preview saves $17.70 |
| Coding / tool-using agent 2,000 tasks — each a multi-step task with tool calls and file context (60,000 in / 6,000 out tokens) | $6.60 | $25.20 | Inception: Mercury 2.5 Preview saves $18.60 |
| Batch summarisation 10,000 documents — each a 6,000-word report summarised to a page (8,000 in / 600 out tokens) | $4.10 | $15.60 | Inception: Mercury 2.5 Preview saves $11.50 |
| Long-document analysis 500 documents — each a 150-page contract or codebase read in one pass (100,000 in / 2,000 out tokens) | $2.15 | $8.10 | Inception: Mercury 2.5 Preview saves $5.95 |
Capabilities side by side
| Capability | Inception: Mercury 2.5 Preview | Mistral: Mistral Small 4 | What it lets you do |
|---|---|---|---|
| Tool / function calling | ✓ Yes | ✓ Yes | call your APIs and run agent loops |
| Structured output (JSON schema) | ✓ Yes | ✓ Yes | return JSON that validates against your schema |
| Reasoning / thinking mode | ✓ Yes | ✓ Yes | spend extra tokens thinking before answering hard problems |
| Image input | — | ✓ Yes | read screenshots, charts and scanned pages |
| Audio input | — | — | take speech or audio directly |
| File / PDF input | — | — | accept documents without your own parsing step |
| Image output | — | — | generate images, not just text |
| Built-in web search | — | — | answer from live web results |
| Seed (reproducible sampling) | — | ✓ Yes | repeat a generation for tests and evals |
| Log-probabilities | — | — | read token confidence for classification and scoring |
From each model's published parameters and input/output types. “—” means not advertised, not proven absent.
Price history
- Inception: Mercury 2.5 Preview: price unchanged since we started tracking it on 2026-09-02.
- Mistral: Mistral Small 4: price unchanged since we started tracking it on 2026-03-31.
Which should you choose?
Choose Mistral: Mistral Small 4 if…
- you need image input — to read screenshots, charts and scanned pages; Inception: Mercury 2.5 Preview does not advertise it
- you need seed (reproducible sampling) — to repeat a generation for tests and evals; Inception: Mercury 2.5 Preview does not advertise it
- you generate long outputs in one go — up to 210K tokens (about 157,300 words) per response
Frequently asked questions
Is Inception: Mercury 2.5 Preview better than Mistral: Mistral Small 4?
Neither wins outright: Inception: Mercury 2.5 Preview is the pick when cost matters at scale, Mistral: Mistral Small 4 when you need image input. In short: Inception: Mercury 2.5 Preview when cost matters at scale, you want the newer model; Mistral: Mistral Small 4 when you need image input, you need seed (reproducible sampling), you generate long outputs in one go.
Which is cheaper, Inception: Mercury 2.5 Preview or Mistral: Mistral Small 4?
Inception: Mercury 2.5 Preview is cheaper: $0.07 vs $0.26 per 1M tokens at a typical 3:1 input/output mix, 74% less. For 50,000 support conversations a month that is $6.00 against $23.25.
How much do Inception: Mercury 2.5 Preview and Mistral: Mistral Small 4 cost per million tokens?
Inception: Mercury 2.5 Preview costs $0.04 per 1M input tokens and $0.15 per 1M output tokens; Mistral: Mistral Small 4 costs $0.15 input and $0.60 output. Output tokens are billed separately, so long answers shift the gap.
Which has the bigger context window, Inception: Mercury 2.5 Preview or Mistral: Mistral Small 4?
Mistral: Mistral Small 4: 262K tokens, about 393 pages, against 260K (about 390 pages) for Inception: Mercury 2.5 Preview.
Do Inception: Mercury 2.5 Preview and Mistral: Mistral Small 4 support function calling and JSON output?
Tool calling — Inception: Mercury 2.5 Preview: yes, Mistral: Mistral Small 4: yes. JSON-schema structured output — Inception: Mercury 2.5 Preview: yes, Mistral: Mistral Small 4: yes.
Can Inception: Mercury 2.5 Preview or Mistral: Mistral Small 4 read images?
Only Mistral: Mistral Small 4 accepts image input; Inception: Mercury 2.5 Preview is text-only for input.
Is Inception: Mercury 2.5 Preview or Mistral: Mistral Small 4 free to use?
No free variant is listed for either; both are pay-per-token.
What is the maximum output length of Inception: Mercury 2.5 Preview and Mistral: Mistral Small 4?
Inception: Mercury 2.5 Preview can write up to 66K tokens (about 49,200 words) per response; Mistral: Mistral Small 4 up to 210K (about 157,300 words).
When were Inception: Mercury 2.5 Preview and Mistral: Mistral Small 4 released?
Inception: Mercury 2.5 Preview was listed on 2026-08-31; Mistral: Mistral Small 4 on 2026-03-16.
About the two models
Inception: Mercury 2.5 Preview
Mercury 2.5 is the fastest reasoning LLM, and the latest diffusion LLM (dLLM) from Inception. Instead of generating tokens sequentially, Mercury 2.5 produces and refines multiple tokens in parallel, achieving...
Full Inception: Mercury 2.5 Preview specs →Mistral: Mistral Small 4
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. It combines strong reasoning from...
Full Mistral: Mistral Small 4 specs →