Mistral Small 3.1 24B vs o3 Mini
Mistral Small 3.1 24B costs 7.9x less per output token than o3 Mini ($0.555 vs $4.40 per million). Updated October 21, 2026; 28 benchmarks have a result for both.
Mistral Small 3.1 24B or o3 Mini: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Mistral Small 3.1 24B for output tokens 7.9x cheaper ($0.555 vs $4.40 per million) and work measured by LMArena Text: coding or LMArena Text: software and IT, where it leads.
- Shared results
- 28
- Mistral Small 3.1 24B only
- 10
- o3 Mini only
- 42
- Like-for-like categories
- 5 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
No call
Only o3 Mini has a AA Intelligence Index result, 12.5.
Directional only
Reasoning
GPQA Diamond
No call
Only o3 Mini has a GPQA Diamond result, 75.5%.
Directional only
Math
AIME
No call
Only o3 Mini has a AIME result, 86.5%.
Directional only
Knowledge
MMLU Pro
No call
Only o3 Mini has a MMLU Pro result, 78.7%.
Directional only
Long documents
Listed context window
o3 Mini
o3 Mini takes 200K tokens against 128K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mistral Small 3.1 24B
Mistral Small 3.1 24B $0.0006, o3 Mini $0.0033 per turn.
List prices
At a glance
- Coding index
- Mistral Small 3.1 24B not benchmarked, o3 Mini not benchmarked.
- Widest category
- Math, 21.8 points apart on average over 2 shared benchmarks.
- Widest single gap
- LMArena Text: math: Mistral Small 3.1 24B 1261 against o3 Mini 1396, 22.4 points apart on a 0 to 100 scale.
- Output price
- Mistral Small 3.1 24B $0.555 against o3 Mini $4.40 per million output tokens, 7.9x apart.
- Context window
- Mistral Small 3.1 24B takes 128K tokens, o3 Mini 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 3.1 24B | Bars | o3 Mini | Ties |
|---|---|---|---|---|
| Coding | 0 | 2 | ||
| Reasoning | 0 | 3 | ||
| Math | 0 | 2 | ||
| Knowledge | 0 | 4 | ||
| General | 0 | 17 | ||
| All shared boards | 0 | 28 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index02
| Benchmark | Mistral Small 3.1 24B | o3 Mini | Leader |
|---|---|---|---|
| Aider polyglot | Not measured | 60.4% | Only o3 Mini measured |
| SWE-bench Verified | Not measured | 42.4% | Only o3 Mini measured |
| SWE-bench Lite | Not measured | 32.3% | Only o3 Mini measured |
| LiveCodeBench (Vals AI) | Not measured | 71.5% | Only o3 Mini measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 73.4% | Only o3 Mini measured |
| SciCode | Not measured | 42.8% | Only o3 Mini measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 6.8% | Only o3 Mini measured |
| GSO-Bench | Not measured | 1.3% | Only o3 Mini measured |
| WeirdML | Not measured | 43.7% | Only o3 Mini measured |
| Cybench | Not measured | 22.5% | Only o3 Mini measured |
| LMArena Text: coding | 1309 | 1378 | o3 Mini |
| LMArena Text: software and IT | 1301 | 1364 | o3 Mini |
| Neither model has a result on the other 26 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Mistral Small 3.1 24B | o3 Mini | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 12.5 | Only o3 Mini measured |
| Epoch Capabilities Index | Not measured | 140.2 | Only o3 Mini measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Mistral Small 3.1 24B | o3 Mini | Leader |
|---|---|---|---|
| τ²-Bench Telecom | Not measured | 31.3% | Only o3 Mini measured |
| Neither model has a result on the other 38 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | Mistral Small 3.1 24B | o3 Mini | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 75.5% | Only o3 Mini measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 77.3% | Only o3 Mini measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 12.0% | Only o3 Mini measured |
| GPQA Diamond (Epoch AI run) | Not measured | 77.0% | Only o3 Mini measured |
| ARC-AGI | Not measured | 34.5% | Only o3 Mini measured |
| ARC-AGI-2 | Not measured | 3.0% | Only o3 Mini measured |
| SimpleBench | Not measured | 22.8% | Only o3 Mini measured |
| Chess puzzles | Not measured | 15.0% | Only o3 Mini measured |
| Mystery game puzzles | Not measured | 7.0% | Only o3 Mini measured |
| LMArena Text: hard prompts | 1278 | 1365 | o3 Mini |
| LMArena Text: expert | 1257 | 1364 | o3 Mini |
| LMArena Text: hard prompts in English | 1290 | 1375 | o3 Mini |
| LMArena Vision: diagrams | 1119 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Vision: homework | 1158 | Not measured | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 7 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Mistral Small 3.1 24B | o3 Mini | Leader |
|---|---|---|---|
| AIME | Not measured | 86.5% | Only o3 Mini measured |
| MATH 500 (Vals AI) | Not measured | 91.8% | Only o3 Mini measured |
| MGSM (Vals AI) | Not measured | 91.3% | Only o3 Mini measured |
| OTIS Mock AIME | Not measured | 76.9% | Only o3 Mini measured |
| FrontierMath, tiers 1 to 3 | Not measured | 18.6% | Only o3 Mini measured |
| FrontierMath, tier 4 | Not measured | 0.0% | Only o3 Mini measured |
| MATH level 5 | Not measured | 96.5% | Only o3 Mini measured |
| LMArena Text: math | 1261 | 1396 | o3 Mini |
| LMArena Text: mathematical work | 1271 | 1399 | o3 Mini |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | Mistral Small 3.1 24B | o3 Mini | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 78.7% | Only o3 Mini measured |
| LegalBench (Vals AI) | Not measured | 71.5% | Only o3 Mini measured |
| CorpFin (Vals AI) | Not measured | 45.3% | Only o3 Mini measured |
| TaxEval (Vals AI) | Not measured | 69.4% | Only o3 Mini measured |
| MedQA (Vals AI) | Not measured | 94.8% | Only o3 Mini measured |
| MMLU Pro (Artificial Analysis run) | Not measured | 80.2% | Only o3 Mini measured |
| SimpleQA Verified | Not measured | 15.3% | Only o3 Mini measured |
| LMArena Text: science | 1265 | 1339 | o3 Mini |
| LMArena Text: medicine and healthcare | 1267 | 1330 | o3 Mini |
| LMArena Text: legal and government | 1271 | 1328 | o3 Mini |
| LMArena Text: business and finance | 1257 | 1313 | o3 Mini |
| Neither model has a result on the other 6 boards here | |||
Web designNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Mistral Small 3.1 24B | o3 Mini | Leader |
|---|---|---|---|
| Neither model has a result on 9 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index017
| Benchmark | Mistral Small 3.1 24B | o3 Mini | Leader |
|---|---|---|---|
| IFBench | Not measured | 67.1% | Only o3 Mini measured |
| Long context reasoning (AA-LCR) | Not measured | 43.0% | Only o3 Mini measured |
| DTBench | Not measured | 68.8% | Only o3 Mini measured |
| LMCA | Not measured | 19.0% | Only o3 Mini measured |
| Fiction.LiveBench | Not measured | 50.0% | Only o3 Mini measured |
| Creative writing (Lech Mazur) | Not measured | 61.7% | Only o3 Mini measured |
| LMArena Text | 1277 | 1337 | o3 Mini |
| LMArena Text: instruction following | 1263 | 1337 | o3 Mini |
| LMArena Text: creative writing | 1252 | 1286 | o3 Mini |
| LMArena Vision | 1136 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: English | 1295 | 1351 | o3 Mini |
| LMArena Text: non-English | 1255 | 1319 | o3 Mini |
| LMArena Text: Chinese | 1253 | 1379 | o3 Mini |
| LMArena Text: German | 1266 | 1303 | o3 Mini |
| LMArena Text: Japanese | 1208 | 1286 | o3 Mini |
| LMArena Text: Korean | 1207 | 1313 | o3 Mini |
| LMArena Text: French | 1273 | 1334 | o3 Mini |
| LMArena Text: Spanish | 1284 | 1321 | o3 Mini |
| LMArena Text: Russian | 1263 | 1304 | o3 Mini |
| LMArena Text: Polish | 1242 | 1294 | o3 Mini |
| LMArena Text: multi-turn | 1270 | 1320 | o3 Mini |
| LMArena Text: longer queries | 1299 | 1343 | o3 Mini |
| LMArena Text: writing and language | 1268 | 1313 | o3 Mini |
| LMArena Text: entertainment and media | 1250 | 1283 | o3 Mini |
| LMArena Vision: English | 1157 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Vision: Chinese | 1155 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Vision: reading text | 1132 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Vision: humor | 1142 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Vision: captioning | 1153 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Vision: recognizing things | 1155 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Vision: creative writing | 1123 | Not measured | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 15 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Mistral Small 3.1 24B | o3 Mini | 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 3.1 24B costs less
Repository review
50K input + 3K output tokens
Mistral Small 3.1 24B costs less
Agent loop
200K input + 10K output tokens
Mistral Small 3.1 24B 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 3.1 24B | OpenAI o3 Mini |
|---|---|---|
| Maker | Mistral AI | OpenAI |
| Weights | Open weights | No public weights listed |
| Released | March 17, 2025 | January 31, 2025 |
| Context window | 128K | 200K |
| Input $/Mtok | $0.351 | $1.10 |
| Output $/Mtok | $0.555 | $4.40 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Mistral Small 3.1 24B better than o3 Mini for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Mistral Small 3.1 24B for output tokens 7.9x cheaper ($0.555 vs $4.40 per million) and work measured by LMArena Text: coding or LMArena Text: software and IT, where it leads.
Which is cheaper, Mistral Small 3.1 24B or o3 Mini?
Mistral Small 3.1 24B costs $0.351 per million input tokens and $0.555 per million output tokens; o3 Mini costs $1.10 and $4.40. Cost per solved task is known for neither of them.
Which has the bigger context window, Mistral Small 3.1 24B or o3 Mini?
o3 Mini, with 200K tokens against 128K.
How many benchmarks is the Mistral Small 3.1 24B vs o3 Mini comparison based on?
28 benchmarks have a result for both models as of October 21, 2026. Mistral Small 3.1 24B's coding index rests on 0 independent benchmarks and o3 Mini's on 0. Where only one model has a result, the page says so instead of naming a winner.