GPT-4.1 Mini vs GPT-5.1-Codex
Updated October 21, 2026. 18 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick GPT-5.1-Codex for coding: it scores 50.5 on the Vibe Coding Index against 28.5 for GPT-4.1 Mini.
Pick GPT-4.1 Mini when output tokens cost 6.3x less, or when the context window is larger, 1.05M against 400K tokens.
- Shared results
- 18
- GPT-4.1 Mini only
- 66
- GPT-5.1-Codex only
- 8
- Like-for-like categories
- 8 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
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, four public coding benchmarks
GPT-5.1-Codex
GPT-5.1-Codex scores 50.5 against 28.5.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
GPT-5.1-Codex
GPT-5.1-Codex leads, 23.7 against 10.2.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only GPT-4.1 Mini has a GPQA Diamond result, 67.9%.
Directional only
Math
AIME
No call
Only GPT-4.1 Mini has a AIME result, 49.4%.
Directional only
Knowledge
MMLU Pro
No call
Only GPT-4.1 Mini has a MMLU Pro result, 77.2%.
Directional only
Web design
Design Arena: websites
GPT-5.1-Codex
GPT-5.1-Codex leads, 1162 against 997.
Same board, both measured
Long documents
Listed context window
GPT-4.1 Mini
GPT-4.1 Mini takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-4.1 Mini
GPT-4.1 Mini $0.0012, GPT-5.1-Codex $0.0063 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
GPT-5.1-Codex
GPT-4.1 Mini $1.818, GPT-5.1-Codex $0.892.
Published attempt cost and pass rate
At a glance
- Coding index
- GPT-4.1 Mini 28.5 from 2 benchmarks, GPT-5.1-Codex 50.5 from 2 benchmarks.
- Widest category
- Math, 49.4 points apart on average over 2 shared benchmarks.
- Widest single gap
- AA Math Index: GPT-4.1 Mini 46.3 against GPT-5.1-Codex 95.7, 49.4 points apart on a 0 to 100 scale.
- Output price
- GPT-4.1 Mini $1.60 against GPT-5.1-Codex $10.00 per million output tokens, 6.3x apart.
- Context window
- GPT-4.1 Mini takes 1.05M tokens, GPT-5.1-Codex 400K.
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 | GPT-4.1 Mini | Bars | GPT-5.1-Codex | Ties |
|---|---|---|---|---|
| Coding | 0 | 4 | ||
| Intelligence | 0 | 1 | ||
| Agentic work | 0 | 1 | ||
| Reasoning | 0 | 2 | ||
| Math | 0 | 2 | ||
| Knowledge | 0 | 1 | ||
| Web design | 0 | 5 | ||
| General | 0 | 2 | ||
| All shared boards | 0 | 18 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index04
| Benchmark | GPT-4.1 Mini | GPT-5.1-Codex | Leader |
|---|---|---|---|
| Aider polyglot | 32.4% | Not measured | Only GPT-4.1 Mini measured |
| SWE-bench Verified | 23.9% | 66.0% | GPT-5.1-Codex |
| LMArena WebDev | Not measured | 1337 | Only GPT-5.1-Codex measured |
| AA Coding Index | 20.2 | Not measured | Only GPT-4.1 Mini measured |
| LiveCodeBench (Vals AI) | 58.2% | 85.5% | GPT-5.1-Codex |
| Vibe Code Bench (Vals AI) | Not measured | 13.1% | Only GPT-5.1-Codex measured |
| LiveCodeBench (Artificial Analysis run) | 48.3% | 84.9% | GPT-5.1-Codex |
| Terminal-Bench Hard (Artificial Analysis run) | 7.6% | 34.8% | GPT-5.1-Codex |
| Terminal-Bench | Not measured | 57.8% | Only GPT-5.1-Codex measured |
| WeirdML | 37.6% | Not measured | Only GPT-4.1 Mini measured |
| ALE-Bench | Not measured | 1244.9 | Only GPT-5.1-Codex measured |
| LMArena Text: coding | 1367 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: software and IT | 1360 | Not measured | Only GPT-4.1 Mini measured |
| LMArena WebDev: HTML | Not measured | 1346 | Only GPT-5.1-Codex measured |
| Neither model has a result on the other 24 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-4.1 Mini | GPT-5.1-Codex | Leader |
|---|---|---|---|
| AA Intelligence Index | 10.2 | 23.7 | GPT-5.1-Codex |
| Epoch Capabilities Index | 134.9 | Not measured | Only GPT-4.1 Mini measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-4.1 Mini | GPT-5.1-Codex | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | Not measured | 1018 | Only GPT-5.1-Codex measured |
| Design Arena: agents building full-stack apps | Not measured | 1086 | Only GPT-5.1-Codex measured |
| Design Arena: agents building mobile apps | Not measured | 1191 | Only GPT-5.1-Codex measured |
| τ²-Bench Telecom | 52.9% | 83.0% | GPT-5.1-Codex |
| Neither model has a result on the other 35 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | GPT-4.1 Mini | GPT-5.1-Codex | Leader |
|---|---|---|---|
| GPQA Diamond | 67.9% | Not measured | Only GPT-4.1 Mini measured |
| MMMU Pro (Vals AI) | 70.5% | Not measured | Only GPT-4.1 Mini measured |
| GPQA Diamond (Artificial Analysis run) | 66.4% | 86.0% | GPT-5.1-Codex |
| Humanity's Last Exam (Artificial Analysis run) | 5.0% | 25.7% | GPT-5.1-Codex |
| GPQA Diamond (Epoch AI run) | 65.8% | Not measured | Only GPT-4.1 Mini measured |
| ARC-AGI | 3.5% | Not measured | Only GPT-4.1 Mini measured |
| ARC-AGI-2 | 0.0% | Not measured | Only GPT-4.1 Mini measured |
| Chess puzzles | 1.0% | Not measured | Only GPT-4.1 Mini measured |
| Mystery game puzzles | 7.0% | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: hard prompts | 1349 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: expert | 1338 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: hard prompts in English | 1362 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: diagrams | 1182 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: homework | 1214 | Not measured | Only GPT-4.1 Mini 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 | GPT-4.1 Mini | GPT-5.1-Codex | Leader |
|---|---|---|---|
| AIME | 49.4% | Not measured | Only GPT-4.1 Mini measured |
| MATH 500 (Vals AI) | 88.0% | Not measured | Only GPT-4.1 Mini measured |
| MGSM (Vals AI) | 87.8% | Not measured | Only GPT-4.1 Mini measured |
| AA Math Index | 46.3 | 95.7 | GPT-5.1-Codex |
| AIME 2025 (Artificial Analysis run) | 46.3% | 95.7% | GPT-5.1-Codex |
| OTIS Mock AIME | 44.7% | Not measured | Only GPT-4.1 Mini measured |
| FrontierMath, tiers 1 to 3 | 6.7% | Not measured | Only GPT-4.1 Mini measured |
| MATH level 5 | 87.3% | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: math | 1343 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: mathematical work | 1347 | Not measured | Only GPT-4.1 Mini measured |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-4.1 Mini | GPT-5.1-Codex | Leader |
|---|---|---|---|
| MMLU Pro | 77.2% | Not measured | Only GPT-4.1 Mini measured |
| LegalBench (Vals AI) | 78.0% | Not measured | Only GPT-4.1 Mini measured |
| CorpFin (Vals AI) | 57.9% | Not measured | Only GPT-4.1 Mini measured |
| TaxEval (Vals AI) | 71.9% | Not measured | Only GPT-4.1 Mini measured |
| MortgageTax (Vals AI) | 65.5% | Not measured | Only GPT-4.1 Mini measured |
| MedQA (Vals AI) | 84.6% | Not measured | Only GPT-4.1 Mini measured |
| MMLU Pro (Artificial Analysis run) | 78.1% | 86.0% | GPT-5.1-Codex |
| SimpleQA Verified | 12.7% | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: science | 1328 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: medicine and healthcare | 1324 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: legal and government | 1343 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: business and finance | 1322 | Not measured | Only GPT-4.1 Mini measured |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | GPT-4.1 Mini | GPT-5.1-Codex | Leader |
|---|---|---|---|
| Design Arena: websites | 997 | 1162 | GPT-5.1-Codex |
| Design Arena: UI components | 961 | 1237 | GPT-5.1-Codex |
| Design Arena: game dev | 1071 | 1138 | GPT-5.1-Codex |
| Design Arena: data viz | 1034 | 1213 | GPT-5.1-Codex |
| Design Arena: 3D | 837 | Not measured | Only GPT-4.1 Mini measured |
| Design Arena: all code categories | 994 | 1153 | GPT-5.1-Codex |
| Neither model has a result on the other 3 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | GPT-4.1 Mini | GPT-5.1-Codex | Leader |
|---|---|---|---|
| IFBench | 38.3% | 70.0% | GPT-5.1-Codex |
| Long context reasoning (AA-LCR) | 44.0% | 69.3% | GPT-5.1-Codex |
| DTBench | 68.8% | Not measured | Only GPT-4.1 Mini measured |
| LMCA | 21.1% | Not measured | Only GPT-4.1 Mini measured |
| Fiction.LiveBench | 44.4% | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text | 1341 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: instruction following | 1333 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: creative writing | 1299 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision | 1181 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: English | 1356 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: non-English | 1318 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: Chinese | 1329 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: German | 1350 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: Japanese | 1290 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: Korean | 1298 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: French | 1358 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: Spanish | 1319 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: Russian | 1324 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: Polish | 1326 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: multi-turn | 1354 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: longer queries | 1344 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: writing and language | 1319 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Text: entertainment and media | 1300 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: English | 1191 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: Chinese | 1186 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: reading text | 1188 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: humor | 1182 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: captioning | 1174 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: recognizing things | 1187 | Not measured | Only GPT-4.1 Mini measured |
| LMArena Vision: creative writing | 1182 | Not measured | Only GPT-4.1 Mini measured |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-4.1 Mini | GPT-5.1-Codex | 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
GPT-4.1 Mini costs less
Repository review
50K input + 3K output tokens
GPT-4.1 Mini costs less
Agent loop
200K input + 10K output tokens
GPT-4.1 Mini 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-4.1 Mini | OpenAI GPT-5.1-Codex |
|---|---|---|
| Maker | OpenAI | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | April 14, 2025 | November 13, 2025 |
| Context window | 1.05M | 400K |
| Input $/Mtok | $0.40 | $1.25 |
| Output $/Mtok | $1.60 | $10.00 |
| Coding index | 28.5 | 50.5 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | $1.818 | $0.892 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-4.1 Mini better than GPT-5.1-Codex for coding?
Pick GPT-5.1-Codex for coding: it scores 50.5 on the Vibe Coding Index against 28.5 for GPT-4.1 Mini. Pick GPT-4.1 Mini when output tokens cost 6.3x less, or when the context window is larger, 1.05M against 400K tokens.
Which is cheaper, GPT-4.1 Mini or GPT-5.1-Codex?
GPT-4.1 Mini costs $0.40 per million input tokens and $1.60 per million output tokens; GPT-5.1-Codex costs $1.25 and $10.00. Per solved SWE-bench Verified task, GPT-4.1 Mini costs $1.818 and GPT-5.1-Codex $0.892.
Which has the bigger context window, GPT-4.1 Mini or GPT-5.1-Codex?
GPT-4.1 Mini, with 1.05M tokens against 400K.
How many benchmarks is the GPT-4.1 Mini vs GPT-5.1-Codex comparison based on?
18 benchmarks have a result for both models as of October 21, 2026. GPT-4.1 Mini's coding index rests on 2 independent benchmarks and GPT-5.1-Codex's on 2. Where only one model has a result, the page says so instead of naming a winner.