Mistral Small 4 vs o3 Pro
o3 Pro leads Mistral Small 4 on the Artificial Analysis Intelligence Index, 21.9 to 11.3, and Mistral Small 4 costs 133.3x less per output token ($0.60 vs $80.00 per million). Updated October 22, 2026; 5 benchmarks have a result for both.
Mistral Small 4 or o3 Pro: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Mistral Small 4 for output tokens 133.3x cheaper ($0.60 vs $80.00 per million) and a larger context window (262K against 200K tokens).
- Shared results
- 5
- Mistral Small 4 only
- 10
- o3 Pro only
- 7
- Like-for-like categories
- 3 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Neither has a coding score yet.
One side not measured
Intelligence
AA Intelligence Index
o3 Pro
o3 Pro leads, 21.9 against 11.3.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Mistral Small 4 has a AA Agentic Index result, 0.8.
Directional only
Long documents
Listed context window
Mistral Small 4
Mistral Small 4 takes 262K tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mistral Small 4
Mistral Small 4 $0.0004, o3 Pro $0.060 per turn.
List prices
At a glance
- Coding index
- Mistral Small 4 not benchmarked, o3 Pro not benchmarked.
- Widest category
- Reasoning, 19.6 points apart on average over 2 shared benchmarks.
- Widest single gap
- Kagi LLM Benchmark: Mistral Small 4 40.5% against o3 Pro 72.1%, 31.6 points apart on a 0 to 100 scale.
- Output price
- Mistral Small 4 $0.60 against o3 Pro $80.00 per million output tokens, 133.3x apart.
- Context window
- Mistral Small 4 takes 262K tokens, o3 Pro 200K.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Mistral Small 4 | Bars | o3 Pro | Ties |
|---|---|---|---|---|
| Intelligence | 0 | 1 | ||
| Reasoning | 0 | 2 | ||
| General | 0 | 2 | ||
| All shared boards | 0 | 5 |
CodingDirectional onlySix of these boards feed the Vibe Coding Index7 boards, none shared
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| Aider polyglot | Not measured | 84.9% | Only o3 Pro measured |
| AA Coding Index | 26.6 | Not measured | Only Mistral Small 4 measured |
| Vibe Code Bench (Vals AI) | 0.0% | Not measured | Only Mistral Small 4 measured |
| SciCode | 38.8% | Not measured | Only Mistral Small 4 measured |
| Terminal-Bench Hard (Artificial Analysis run) | 17.4% | Not measured | Only Mistral Small 4 measured |
| WeirdML | Not measured | 58.2% | Only o3 Pro measured |
| ALE-Bench | 497.6 | Not measured | Only Mistral Small 4 measured |
| Neither model has a result on the other 32 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| AA Intelligence Index | 11.3 | 21.9 | o3 Pro |
| Epoch Capabilities Index | Not measured | 147.3 | Only o3 Pro measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| AA Agentic Index | 0.8 | Not measured | Only Mistral Small 4 measured |
| τ²-Bench Telecom | 41.2% | Not measured | Only Mistral Small 4 measured |
| Neither model has a result on the other 39 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | 76.9% | 84.5% | o3 Pro |
| Humanity's Last Exam (Artificial Analysis run) | 9.9% | Not measured | Only Mistral Small 4 measured |
| ARC-AGI | Not measured | 59.3% | Only o3 Pro measured |
| ARC-AGI-2 | Not measured | 4.9% | Only o3 Pro measured |
| Kagi LLM Benchmark | 40.5% | 72.1% | o3 Pro |
| Neither model has a result on the other 17 boards here | |||
MathNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 13 boards here | |||
KnowledgeNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 18 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| IFBench | 48.2% | Not measured | Only Mistral Small 4 measured |
| Long context reasoning (AA-LCR) | 49.7% | Not measured | Only Mistral Small 4 measured |
| DTBench | 70.9% | 86.9% | o3 Pro |
| LMCA | 20.6% | 38.5% | o3 Pro |
| Fiction.LiveBench | Not measured | 97.2% | Only o3 Pro measured |
| Creative writing (Lech Mazur) | Not measured | 84.4% | Only o3 Pro measured |
| Neither model has a result on the other 40 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Mistral Small 4 | o3 Pro | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Mistral Small 4 costs less
Repository review
50K input + 3K output tokens
Mistral Small 4 costs less
Agent loop
200K input + 10K output tokens
Mistral Small 4 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Mistral Small 4 | OpenAI o3 Pro |
|---|---|---|
| Maker | Mistral AI | OpenAI |
| Weights | Open weights | No public weights listed |
| Released | March 16, 2026 | June 10, 2025 |
| Context window | 262K | 200K |
| Input $/Mtok | $0.15 | $20.00 |
| Output $/Mtok | $0.60 | $80.00 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 1 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Mistral Small 4 better than o3 Pro for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Mistral Small 4 for output tokens 133.3x cheaper ($0.60 vs $80.00 per million) and a larger context window (262K against 200K tokens).
Which is cheaper, Mistral Small 4 or o3 Pro?
Mistral Small 4 costs $0.15 per million input tokens and $0.60 per million output tokens; o3 Pro costs $20.00 and $80.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Mistral Small 4 or o3 Pro?
Mistral Small 4, with 262K tokens against 200K.
How many benchmarks is the Mistral Small 4 vs o3 Pro comparison based on?
5 benchmarks have a result for both models as of October 22, 2026. Mistral Small 4's coding index rests on 1 independent benchmark and o3 Pro's on 0. Where only one model has a result, the page says so instead of naming a winner.