GPT-5.1-Codex vs Mistral Small 3.1 24B
Mistral Small 3.1 24B costs 18.0x less per output token than GPT-5.1-Codex ($0.555 vs $10.00 per million). Updated October 21, 2026; no benchmark has tested both models yet.
- Coding
- 15.3
- Overall
- No data
- Output $/M
- $10.00
- Coding
- No data
- Overall
- No data
- Output $/M
- $0.555
GPT-5.1-Codex or Mistral Small 3.1 24B: which to pick
Only GPT-5.1-Codex has a coding score, 15.3 on the Vibe Coding Index; Mistral Small 3.1 24B has none, so the two cannot be ranked on coding.
Pick Mistral Small 3.1 24B for output tokens 18.0x cheaper ($0.555 vs $10.00 per million).
No benchmark has tested both yet. GPT-5.1-Codex has results on SWE-bench Verified, LMArena WebDev and LiveCodeBench (Vals AI); Mistral Small 3.1 24B on LMArena Text: coding, LMArena Text: software and IT and LMArena Text: hard prompts. 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
Only GPT-5.1-Codex has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
No call
Only GPT-5.1-Codex has a AA Intelligence Index result, 23.7.
Directional only
Web design
Design Arena: websites
No call
Only GPT-5.1-Codex has a Design Arena: websites result, 1162.
Directional only
Long documents
Listed context window
GPT-5.1-Codex
GPT-5.1-Codex takes 400K tokens against 128K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mistral Small 3.1 24B
GPT-5.1-Codex $0.0063, Mistral Small 3.1 24B $0.0006 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5.1-Codex has the number, $0.892.
Directional only
At a glance
- Coding index
- GPT-5.1-Codex 15.3 from 2 benchmarks, Mistral Small 3.1 24B 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
- GPT-5.1-Codex $10.00 against Mistral Small 3.1 24B $0.555 per million output tokens, 18.0x apart.
- Context window
- GPT-5.1-Codex takes 400K tokens, Mistral Small 3.1 24B 128K.
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 Index11 boards measured
| Benchmark | GPT-5.1-Codex | Mistral Small 3.1 24B | Leader |
|---|---|---|---|
| SWE-bench Verified | 66.0% | Not measured | Only GPT-5.1-Codex measured |
| LMArena WebDev | 1337 | Not measured | Only GPT-5.1-Codex measured |
| LiveCodeBench (Vals AI) | 85.5% | Not measured | Only GPT-5.1-Codex measured |
| Vibe Code Bench (Vals AI) | 13.1% | Not measured | Only GPT-5.1-Codex measured |
| LiveCodeBench (Artificial Analysis run) | 84.9% | Not measured | Only GPT-5.1-Codex measured |
| Terminal-Bench Hard (Artificial Analysis run) | 34.8% | Not measured | Only GPT-5.1-Codex measured |
| Terminal-Bench | 57.8% | Not measured | Only GPT-5.1-Codex measured |
| ALE-Bench | 1244.9 | Not measured | Only GPT-5.1-Codex measured |
| LMArena Text: coding | Not measured | 1309 | Only Mistral Small 3.1 24B measured |
| LMArena Text: software and IT | Not measured | 1301 | Only Mistral Small 3.1 24B measured |
| LMArena WebDev: HTML | 1346 | Not measured | Only GPT-5.1-Codex measured |
| Neither model has a result on the other 28 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | GPT-5.1-Codex | Mistral Small 3.1 24B | Leader |
|---|---|---|---|
| AA Intelligence Index | 23.7 | Not measured | Only GPT-5.1-Codex measured |
| Neither model has a result on the other 1 board here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index4 boards measured
| Benchmark | GPT-5.1-Codex | Mistral Small 3.1 24B | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1018 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: agents building full-stack apps | 1086 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: agents building mobile apps | 1191 | Not measured | Only GPT-5.1-Codex measured |
| τ²-Bench Telecom | 83.0% | Not measured | Only GPT-5.1-Codex measured |
| Neither model has a result on the other 37 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index7 boards measured
| Benchmark | GPT-5.1-Codex | Mistral Small 3.1 24B | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | 86.0% | Not measured | Only GPT-5.1-Codex measured |
| Humanity's Last Exam (Artificial Analysis run) | 25.7% | Not measured | Only GPT-5.1-Codex measured |
| LMArena Text: hard prompts | Not measured | 1278 | Only Mistral Small 3.1 24B measured |
| LMArena Text: expert | Not measured | 1257 | Only Mistral Small 3.1 24B measured |
| LMArena Text: hard prompts in English | Not measured | 1290 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: diagrams | Not measured | 1119 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: homework | Not measured | 1158 | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 15 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index4 boards measured
| Benchmark | GPT-5.1-Codex | Mistral Small 3.1 24B | Leader |
|---|---|---|---|
| AA Math Index | 95.7 | Not measured | Only GPT-5.1-Codex measured |
| AIME 2025 (Artificial Analysis run) | 95.7% | Not measured | Only GPT-5.1-Codex measured |
| LMArena Text: math | Not measured | 1261 | Only Mistral Small 3.1 24B measured |
| LMArena Text: mathematical work | Not measured | 1271 | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 9 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index5 boards measured
| Benchmark | GPT-5.1-Codex | Mistral Small 3.1 24B | Leader |
|---|---|---|---|
| MMLU Pro (Artificial Analysis run) | 86.0% | Not measured | Only GPT-5.1-Codex measured |
| LMArena Text: science | Not measured | 1265 | Only Mistral Small 3.1 24B measured |
| LMArena Text: medicine and healthcare | Not measured | 1267 | Only Mistral Small 3.1 24B measured |
| LMArena Text: legal and government | Not measured | 1271 | Only Mistral Small 3.1 24B measured |
| LMArena Text: business and finance | Not measured | 1257 | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 13 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index5 boards measured
| Benchmark | GPT-5.1-Codex | Mistral Small 3.1 24B | Leader |
|---|---|---|---|
| Design Arena: websites | 1162 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: UI components | 1237 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: game dev | 1138 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: data viz | 1213 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: all code categories | 1152 | Not measured | Only GPT-5.1-Codex measured |
| Neither model has a result on the other 4 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index27 boards measured
| Benchmark | GPT-5.1-Codex | Mistral Small 3.1 24B | Leader |
|---|---|---|---|
| IFBench | 70.0% | Not measured | Only GPT-5.1-Codex measured |
| Long context reasoning (AA-LCR) | 69.3% | Not measured | Only GPT-5.1-Codex measured |
| LMArena Text | Not measured | 1277 | Only Mistral Small 3.1 24B measured |
| LMArena Text: instruction following | Not measured | 1263 | Only Mistral Small 3.1 24B measured |
| LMArena Text: creative writing | Not measured | 1252 | Only Mistral Small 3.1 24B measured |
| LMArena Vision | Not measured | 1136 | Only Mistral Small 3.1 24B measured |
| LMArena Text: English | Not measured | 1295 | Only Mistral Small 3.1 24B measured |
| LMArena Text: non-English | Not measured | 1255 | Only Mistral Small 3.1 24B measured |
| LMArena Text: Chinese | Not measured | 1253 | Only Mistral Small 3.1 24B measured |
| LMArena Text: German | Not measured | 1266 | Only Mistral Small 3.1 24B measured |
| LMArena Text: Japanese | Not measured | 1208 | Only Mistral Small 3.1 24B measured |
| LMArena Text: Korean | Not measured | 1207 | Only Mistral Small 3.1 24B measured |
| LMArena Text: French | Not measured | 1273 | Only Mistral Small 3.1 24B measured |
| LMArena Text: Spanish | Not measured | 1284 | Only Mistral Small 3.1 24B measured |
| LMArena Text: Russian | Not measured | 1263 | Only Mistral Small 3.1 24B measured |
| LMArena Text: Polish | Not measured | 1242 | Only Mistral Small 3.1 24B measured |
| LMArena Text: multi-turn | Not measured | 1270 | Only Mistral Small 3.1 24B measured |
| LMArena Text: longer queries | Not measured | 1299 | Only Mistral Small 3.1 24B measured |
| LMArena Text: writing and language | Not measured | 1268 | Only Mistral Small 3.1 24B measured |
| LMArena Text: entertainment and media | Not measured | 1250 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: English | Not measured | 1157 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: Chinese | Not measured | 1155 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: reading text | Not measured | 1132 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: humor | Not measured | 1142 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: captioning | Not measured | 1153 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: recognizing things | Not measured | 1155 | Only Mistral Small 3.1 24B measured |
| LMArena Vision: creative writing | Not measured | 1123 | Only Mistral Small 3.1 24B measured |
| Neither model has a result on the other 19 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 | OpenAI GPT-5.1-Codex | Mistral Small 3.1 24B |
|---|---|---|
| Maker | OpenAI | Mistral AI |
| Weights | No public weights listed | Open weights |
| Released | November 13, 2025 | March 17, 2025 |
| Context window | 400K | 128K |
| Input $/Mtok | $1.25 | $0.351 |
| Output $/Mtok | $10.00 | $0.555 |
| Coding index | 15.3 | Not benchmarked |
| Independent measurements behind it | 2 | 0 |
| Cost per solved task | $0.892 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-5.1-Codex better than Mistral Small 3.1 24B for coding?
Only GPT-5.1-Codex has a coding score, 15.3 on the Vibe Coding Index; Mistral Small 3.1 24B has none, so the two cannot be ranked on coding. Pick Mistral Small 3.1 24B for output tokens 18.0x cheaper ($0.555 vs $10.00 per million).
Which is cheaper, GPT-5.1-Codex or Mistral Small 3.1 24B?
GPT-5.1-Codex costs $1.25 per million input tokens and $10.00 per million output tokens; Mistral Small 3.1 24B costs $0.351 and $0.555. Cost per solved task is known for GPT-5.1-Codex only.
Which has the bigger context window, GPT-5.1-Codex or Mistral Small 3.1 24B?
GPT-5.1-Codex, with 400K tokens against 128K.
Has any benchmark tested both GPT-5.1-Codex and Mistral Small 3.1 24B?
No benchmark has tested both yet. GPT-5.1-Codex has results on SWE-bench Verified, LMArena WebDev and LiveCodeBench (Vals AI); Mistral Small 3.1 24B on LMArena Text: coding, LMArena Text: software and IT and LMArena Text: hard prompts. Compare them on price and context instead. Data as of October 21, 2026.