GPT-5.1-Codex-Mini vs Kimi K3
Updated October 21, 2026. 13 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
vs boards won of 13 shared
Decision reading
Pick Kimi K3 for coding: it scores 61.8 on the Vibe Coding Index against 6.2 for GPT-5.1-Codex-Mini.
Pick GPT-5.1-Codex-Mini when output tokens cost 6.0x less.
Model AGPT-5.1-Codex-MiniOpenAI6.2/1001 independent benchmarkNo cost per solved taskModel BKimi K3Moonshot AI61.8/1002 independent benchmarks$0.81 per solved task
- Shared results
- 13
- GPT-5.1-Codex-Mini only
- 9
- Kimi K3 only
- 104
- Like-for-like categories
- 5 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
Kimi K3
Kimi K3 scores 61.8 against 6.2.
1 and 2 benchmarks behind the scores
Intelligence
AA Intelligence Index
Kimi K3
Kimi K3 leads, 43.6 against 20.4.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Kimi K3 has a AA Agentic Index result, 50.0.
Directional only
Reasoning
GPQA Diamond
No call
Only Kimi K3 has a GPQA Diamond result, 92.9%.
Directional only
Knowledge
MMLU Pro
No call
Only Kimi K3 has a MMLU Pro result, 88.0%.
Directional only
Web design
Design Arena: websites
Kimi K3
Kimi K3 leads, 1336 against 1111.
Same board, both measured
General
Vals Index
No call
Only Kimi K3 has a Vals Index result, 53.0%.
Directional only
Long documents
Listed context window
Kimi K3
Kimi K3 takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-5.1-Codex-Mini
GPT-5.1-Codex-Mini $0.0013, Kimi K3 $0.0062 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Kimi K3 has the number, $0.81.
Directional only
At a glance
- Coding index
- GPT-5.1-Codex-Mini 6.2 from 1 benchmark, Kimi K3 61.8 from 2 benchmarks.
- Widest category
- Coding, 58.3 points apart on average over 2 shared benchmarks.
- Widest single gap
- LMArena WebDev: GPT-5.1-Codex-Mini 1244 against Kimi K3 1655, 58.8 points apart on a 0 to 100 scale.
- Output price
- GPT-5.1-Codex-Mini $2.00 against Kimi K3 $11.936 per million output tokens, 6.0x apart.
- Context window
- GPT-5.1-Codex-Mini takes 400K tokens, Kimi K3 1.05M.
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-5.1-Codex-Mini | Bars | Kimi K3 | Ties |
|---|---|---|---|---|
| Coding | 0 | 2 | ||
| Intelligence | 0 | 1 | ||
| Reasoning | 0 | 2 | ||
| Web design | 0 | 7 | ||
| General | 0 | 1 | ||
| All shared boards | 0 | 13 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index02
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 59.3% | Only Kimi K3 measured |
| LMArena WebDev | 1244 | 1655 | Kimi K3 |
| AA Coding Index | Not measured | 76.2 | Only Kimi K3 measured |
| LiveCodeBench (Vals AI) | Not measured | 87.2% | Only Kimi K3 measured |
| SWE-bench Verified (Vals AI) | Not measured | 93.4% | Only Kimi K3 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 17.2% | Only Kimi K3 measured |
| Vibe Code Bench (Vals AI) | Not measured | 85.0% | Only Kimi K3 measured |
| Code migration (Vals AI) | Not measured | 16.1% | Only Kimi K3 measured |
| ProgramBench (Vals AI) | Not measured | 2.0% | Only Kimi K3 measured |
| IOI (Vals AI) | Not measured | 48.9% | Only Kimi K3 measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 80.9% | Only Kimi K3 measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 44.2% | Only Kimi K3 measured |
| Vibe Code Bench 1-100 (Vals AI) | Not measured | 18.2% | Only Kimi K3 measured |
| CyberBench (Vals AI) | Not measured | 75.2% | Only Kimi K3 measured |
| LiveCodeBench (Artificial Analysis run) | 83.6% | Not measured | Only GPT-5.1-Codex-Mini measured |
| SciCode | Not measured | 59.5% | Only Kimi K3 measured |
| Terminal-Bench Hard (Artificial Analysis run) | 33.3% | Not measured | Only GPT-5.1-Codex-Mini measured |
| Terminal-Bench | 61.6% | Not measured | Only GPT-5.1-Codex-Mini measured |
| FrontierCode | Not measured | 44.2% | Only Kimi K3 measured |
| FrontierSWE | Not measured | 25.9% | Only Kimi K3 measured |
| WeirdML | Not measured | 82.6% | Only Kimi K3 measured |
| ALE-Bench | Not measured | 1524.5 | Only Kimi K3 measured |
| LMArena Text: coding | Not measured | 1508 | Only Kimi K3 measured |
| LMArena Text: software and IT | Not measured | 1499 | Only Kimi K3 measured |
| LMArena WebDev: React | Not measured | 1670 | Only Kimi K3 measured |
| LMArena WebDev: HTML | 1253 | 1644 | Kimi K3 |
| LMArena WebDev: from an image | Not measured | 1579 | Only Kimi K3 measured |
| Neither model has a result on the other 11 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 20.4 | 43.6 | Kimi K3 |
| Epoch Capabilities Index | Not measured | 157.9 | Only Kimi K3 measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index25 boards, none shared
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 50.0 | Only Kimi K3 measured |
| Design Arena: agents building web apps | Not measured | 1296 | Only Kimi K3 measured |
| Design Arena: agents building full-stack apps | Not measured | 1315 | Only Kimi K3 measured |
| Design Arena: agents building mobile apps | Not measured | 1267 | Only Kimi K3 measured |
| Design Arena: agents building Android apps | Not measured | 1256 | Only Kimi K3 measured |
| Design Arena: agents building Godot games | Not measured | 1223 | Only Kimi K3 measured |
| Design Arena: agents building games | Not measured | 1252 | Only Kimi K3 measured |
| Design Arena: HTML slides | Not measured | 1256 | Only Kimi K3 measured |
| Design Arena: PowerPoint slides | Not measured | 1273 | Only Kimi K3 measured |
| Design Arena: spreadsheets | Not measured | 1058 | Only Kimi K3 measured |
| LiveBench research | Not measured | 79.0% | Only Kimi K3 measured |
| LiveBench browser | Not measured | 16.0% | Only Kimi K3 measured |
| LiveBench long agentic | Not measured | 42.8% | Only Kimi K3 measured |
| Finance Agent (Vals AI) | Not measured | 53.1% | Only Kimi K3 measured |
| Tax Agent Bench (Vals AI) | Not measured | 33.4% | Only Kimi K3 measured |
| Legal Research Bench (Vals AI) | Not measured | 46.1% | Only Kimi K3 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 12.9% | Only Kimi K3 measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 66.7% | Only Kimi K3 measured |
| BioMysteryBench (Vals AI) | Not measured | 72.6% | Only Kimi K3 measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 1.4% | Only Kimi K3 measured |
| Time Horizon Index (Vals AI) | Not measured | 10.5% | Only Kimi K3 measured |
| τ²-Bench Telecom | 62.9% | Not measured | Only GPT-5.1-Codex-Mini measured |
| APEX-Agents | Not measured | 47.8% | Only Kimi K3 measured |
| PostTrainBench | Not measured | 32.0% | Only Kimi K3 measured |
| Vending-Bench 2 | Not measured | $5,165 | Only Kimi K3 measured |
| Neither model has a result on the other 14 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 92.9% | Only Kimi K3 measured |
| LiveBench reasoning | Not measured | 90.7% | Only Kimi K3 measured |
| MMMU Pro (Vals AI) | Not measured | 88.2% | Only Kimi K3 measured |
| GPQA Diamond (Artificial Analysis run) | 81.3% | 93.5% | Kimi K3 |
| Humanity's Last Exam (Artificial Analysis run) | 18.5% | 46.9% | Kimi K3 |
| GPQA Diamond (Epoch AI run) | Not measured | 93.1% | Only Kimi K3 measured |
| ARC-AGI | Not measured | 94.5% | Only Kimi K3 measured |
| ARC-AGI-2 | Not measured | 60.4% | Only Kimi K3 measured |
| SimpleBench | Not measured | 60.7% | Only Kimi K3 measured |
| Chess puzzles | Not measured | 37.0% | Only Kimi K3 measured |
| Mystery game puzzles | Not measured | 26.0% | Only Kimi K3 measured |
| LMArena Text: hard prompts | Not measured | 1495 | Only Kimi K3 measured |
| LMArena Text: expert | Not measured | 1520 | Only Kimi K3 measured |
| LMArena Text: hard prompts in English | Not measured | 1496 | Only Kimi K3 measured |
| Neither model has a result on the other 7 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | Leader |
|---|---|---|---|
| AA Math Index | 91.7 | Not measured | Only GPT-5.1-Codex-Mini measured |
| AIME 2025 (Artificial Analysis run) | 91.7% | Not measured | Only GPT-5.1-Codex-Mini measured |
| OTIS Mock AIME | Not measured | 97.2% | Only Kimi K3 measured |
| FrontierMath, tiers 1 to 3 | Not measured | 72.2% | Only Kimi K3 measured |
| FrontierMath, tier 4 | Not measured | 39.0% | Only Kimi K3 measured |
| ProofBench | Not measured | 87.0% | Only Kimi K3 measured |
| LMArena Text: math | Not measured | 1494 | Only Kimi K3 measured |
| LMArena Text: mathematical work | Not measured | 1505 | Only Kimi K3 measured |
| Neither model has a result on the other 5 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index12 boards, none shared
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 88.0% | Only Kimi K3 measured |
| LegalBench (Vals AI) | Not measured | 86.2% | Only Kimi K3 measured |
| CorpFin (Vals AI) | Not measured | 71.6% | Only Kimi K3 measured |
| TaxEval (Vals AI) | Not measured | 75.7% | Only Kimi K3 measured |
| MortgageTax (Vals AI) | Not measured | 66.3% | Only Kimi K3 measured |
| MedCode (Vals AI) | Not measured | 49.4% | Only Kimi K3 measured |
| MMLU Pro (Artificial Analysis run) | 82.0% | Not measured | Only GPT-5.1-Codex-Mini measured |
| SimpleQA Verified | Not measured | 50.6% | Only Kimi K3 measured |
| LMArena Text: science | Not measured | 1508 | Only Kimi K3 measured |
| LMArena Text: medicine and healthcare | Not measured | 1489 | Only Kimi K3 measured |
| LMArena Text: legal and government | Not measured | 1503 | Only Kimi K3 measured |
| LMArena Text: business and finance | Not measured | 1470 | Only Kimi K3 measured |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index07
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | Leader |
|---|---|---|---|
| Design Arena: websites | 1111 | 1336 | Kimi K3 |
| Design Arena: UI components | 1081 | 1345 | Kimi K3 |
| Design Arena: game dev | 1093 | 1361 | Kimi K3 |
| Design Arena: data viz | 1097 | 1350 | Kimi K3 |
| Design Arena: 3D | 988 | 1388 | Kimi K3 |
| Design Arena: all code categories | 1094 | 1361 | Kimi K3 |
| Design Arena: SVG | 977 | 1301 | Kimi K3 |
| Design Arena: ASCII art | 1104 | Not measured | Only GPT-5.1-Codex-Mini measured |
| LiveBench design | Not measured | 77.2% | Only Kimi K3 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | Leader |
|---|---|---|---|
| Vals Index | Not measured | 53.0% | Only Kimi K3 measured |
| LiveBench data analysis | Not measured | 78.7% | Only Kimi K3 measured |
| Public Benefits Bench (Vals AI) | Not measured | 68.2% | Only Kimi K3 measured |
| SAGE (Vals AI) | Not measured | 52.8% | Only Kimi K3 measured |
| MedScribe (Vals AI) | Not measured | 88.0% | Only Kimi K3 measured |
| Vals Multimodal Index | Not measured | 73.4% | Only Kimi K3 measured |
| IFBench | 67.9% | Not measured | Only GPT-5.1-Codex-Mini measured |
| Long context reasoning (AA-LCR) | 66.7% | 88.7% | Kimi K3 |
| DTBench | Not measured | 91.2% | Only Kimi K3 measured |
| LMCA | Not measured | 52.7% | Only Kimi K3 measured |
| Surface Evolver Bench | Not measured | 95.0% | Only Kimi K3 measured |
| Furniture assembly | Not measured | 34.2% | Only Kimi K3 measured |
| LMArena Text | Not measured | 1476 | Only Kimi K3 measured |
| LMArena Text: instruction following | Not measured | 1485 | Only Kimi K3 measured |
| LMArena Text: creative writing | Not measured | 1457 | Only Kimi K3 measured |
| LMArena Text: English | Not measured | 1481 | Only Kimi K3 measured |
| LMArena Text: non-English | Not measured | 1466 | Only Kimi K3 measured |
| LMArena Text: Chinese | Not measured | 1529 | Only Kimi K3 measured |
| LMArena Text: German | Not measured | 1490 | Only Kimi K3 measured |
| LMArena Text: Japanese | Not measured | 1494 | Only Kimi K3 measured |
| LMArena Text: Korean | Not measured | 1460 | Only Kimi K3 measured |
| LMArena Text: French | Not measured | 1492 | Only Kimi K3 measured |
| LMArena Text: Spanish | Not measured | 1472 | Only Kimi K3 measured |
| LMArena Text: Russian | Not measured | 1485 | Only Kimi K3 measured |
| LMArena Text: Polish | Not measured | 1458 | Only Kimi K3 measured |
| LMArena Text: multi-turn | Not measured | 1489 | Only Kimi K3 measured |
| LMArena Text: longer queries | Not measured | 1494 | Only Kimi K3 measured |
| LMArena Text: writing and language | Not measured | 1471 | Only Kimi K3 measured |
| LMArena Text: entertainment and media | Not measured | 1453 | Only Kimi K3 measured |
| Neither model has a result on the other 17 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-5.1-Codex-Mini | Kimi K3 | 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-5.1-Codex-Mini$0.0013Fits in one request
Kimi K3$0.0062Fits in one request
GPT-5.1-Codex-Mini costs less
Repository review
50K input + 3K output tokens
GPT-5.1-Codex-Mini$0.018Fits in one request
Kimi K3$0.048Fits in one request
GPT-5.1-Codex-Mini costs less
Agent loop
200K input + 10K output tokens
GPT-5.1-Codex-Mini$0.070Fits in one request
Kimi K3$0.167Fits in one request
GPT-5.1-Codex-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-5.1-Codex-Mini | MoonshotAI Kimi K3 |
|---|---|---|
| Maker | OpenAI | Moonshot AI |
| Weights | No public weights listed | Open weights |
| Released | November 13, 2025 | July 16, 2026 |
| Context window | 400K | 1.05M |
| Input $/Mtok | $0.25 | $0.239 |
| Output $/Mtok | $2.00 | $11.936 |
| Coding index | 6.2 | 61.8 |
| Independent measurements behind it | 1 | 2 |
| Cost per solved task | Not computable | $0.81 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-5.1-Codex-Mini better than Kimi K3 for coding?
Pick Kimi K3 for coding: it scores 61.8 on the Vibe Coding Index against 6.2 for GPT-5.1-Codex-Mini. Pick GPT-5.1-Codex-Mini when output tokens cost 6.0x less.
Which is cheaper, GPT-5.1-Codex-Mini or Kimi K3?
GPT-5.1-Codex-Mini costs $0.25 per million input tokens and $2.00 per million output tokens; Kimi K3 costs $0.239 and $11.936. Cost per solved task is known for Kimi K3 only.
Which has the bigger context window, GPT-5.1-Codex-Mini or Kimi K3?
Kimi K3, with 1.05M tokens against 400K.
How many benchmarks is the GPT-5.1-Codex-Mini vs Kimi K3 comparison based on?
13 benchmarks have a result for both models as of October 21, 2026. GPT-5.1-Codex-Mini's coding index rests on 1 independent benchmark and Kimi K3's on 2. Where only one model has a result, the page says so instead of naming a winner.