Mistral Small 3.1 24B vs o3 Pro
Mistral Small 3.1 24B costs 144.1x less per output token than o3 Pro ($0.555 vs $80.00 per million). Updated October 21, 2026; no benchmark has tested both models yet.
- Coding
- No data
- Overall
- No data
- Output $/M
- $0.555
- Coding
- No data
- Overall
- 21.9
- Output $/M
- $80.00
Mistral Small 3.1 24B or o3 Pro: 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 144.1x cheaper ($0.555 vs $80.00 per million).
No benchmark has tested both yet. Mistral Small 3.1 24B has results on LMArena Text: coding, LMArena Text: software and IT and LMArena Text: hard prompts; o3 Pro on Aider polyglot, WeirdML and AA Intelligence Index. Compare them on price and context instead.
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 Pro has a AA Intelligence Index result, 21.9.
Directional only
Long documents
Listed context window
o3 Pro
o3 Pro 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 Pro $0.060 per turn.
List prices
At a glance
- Coding index
- Mistral Small 3.1 24B not benchmarked, o3 Pro not benchmarked.
- Widest category
- None yet: no category has been tested on both models.
- Widest single gap
- None yet: no benchmark has tested both models.
- Output price
- Mistral Small 3.1 24B $0.555 against o3 Pro $80.00 per million output tokens, 144.1x apart.
- Context window
- Mistral Small 3.1 24B takes 128K tokens, o3 Pro 200K.
Benchmark by benchmark
Every board either model has a result on, a category to a fold; bars are each result on a 0 to 100 scale. Only one model is measured on each, so no row names a leader.
CodingDirectional onlySix of these boards feed the Vibe Coding Index4 boards measured
| Benchmark | Mistral Small 3.1 24B | o3 Pro | Leader |
|---|---|---|---|
| Aider polyglot | Not measured | 84.9% | Only o3 Pro measured |
| WeirdML | Not measured | 58.2% | Only o3 Pro measured |
| LMArena Text: coding | 1309 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: software and IT | 1301 | Not measured | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 34 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | Mistral Small 3.1 24B | o3 Pro | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 21.9 | Only o3 Pro measured |
| Epoch Capabilities Index | Not measured | 147.3 | Only o3 Pro measured |
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index8 boards measured
| Benchmark | Mistral Small 3.1 24B | o3 Pro | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | Not measured | 84.5% | Only o3 Pro measured |
| ARC-AGI | Not measured | 59.3% | Only o3 Pro measured |
| ARC-AGI-2 | Not measured | 4.9% | Only o3 Pro measured |
| LMArena Text: hard prompts | 1278 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: expert | 1257 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: hard prompts in English | 1290 | Not measured | Only Mistral Small 3.1 24B measured |
| 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 13 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | Mistral Small 3.1 24B | o3 Pro | Leader |
|---|---|---|---|
| LMArena Text: math | 1261 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: mathematical work | 1271 | Not measured | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 11 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index4 boards measured
| Benchmark | Mistral Small 3.1 24B | o3 Pro | Leader |
|---|---|---|---|
| LMArena Text: science | 1265 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: medicine and healthcare | 1267 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: legal and government | 1271 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: business and finance | 1257 | Not measured | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 13 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index29 boards measured
| Benchmark | Mistral Small 3.1 24B | o3 Pro | Leader |
|---|---|---|---|
| DTBench | Not measured | 86.9% | Only o3 Pro measured |
| LMCA | Not measured | 38.5% | Only o3 Pro measured |
| Fiction.LiveBench | Not measured | 97.2% | Only o3 Pro measured |
| Creative writing (Lech Mazur) | Not measured | 84.4% | Only o3 Pro measured |
| LMArena Text | 1277 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: instruction following | 1263 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: creative writing | 1252 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Vision | 1136 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: English | 1295 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: non-English | 1255 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: Chinese | 1253 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: German | 1266 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: Japanese | 1208 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: Korean | 1207 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: French | 1273 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: Spanish | 1284 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: Russian | 1263 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: Polish | 1242 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: multi-turn | 1270 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: longer queries | 1299 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: writing and language | 1268 | Not measured | Only Mistral Small 3.1 24B measured |
| LMArena Text: entertainment and media | 1250 | Not measured | Only Mistral Small 3.1 24B measured |
| 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 17 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 Pro |
|---|---|---|
| Maker | Mistral AI | OpenAI |
| Weights | Open weights | No public weights listed |
| Released | March 17, 2025 | June 10, 2025 |
| Context window | 128K | 200K |
| Input $/Mtok | $0.351 | $20.00 |
| Output $/Mtok | $0.555 | $80.00 |
| 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 Pro 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 144.1x cheaper ($0.555 vs $80.00 per million).
Which is cheaper, Mistral Small 3.1 24B or o3 Pro?
Mistral Small 3.1 24B costs $0.351 per million input tokens and $0.555 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 3.1 24B or o3 Pro?
o3 Pro, with 200K tokens against 128K.
Has any benchmark tested both Mistral Small 3.1 24B and o3 Pro?
No benchmark has tested both yet. Mistral Small 3.1 24B has results on LMArena Text: coding, LMArena Text: software and IT and LMArena Text: hard prompts; o3 Pro on Aider polyglot, WeirdML and AA Intelligence Index. Compare them on price and context instead. Data as of October 21, 2026.