GPT-5 Nano vs Kimi K3
Kimi K3 leads GPT-5 Nano on the Artificial Analysis Intelligence Index, 43.6 to 13.0, and GPT-5 Nano costs 37.5x less per output token ($0.40 vs $15.00 per million). Updated October 21, 2026; 61 benchmarks have a result for both.
GPT-5 Nano or Kimi K3: which to pick
Only Kimi K3 has a coding score, 62.3 on the Vibe Coding Index; GPT-5 Nano has none, so the two cannot be ranked on coding.
Pick GPT-5 Nano for output tokens 37.5x cheaper ($0.40 vs $15.00 per million) and a lower cost per solved task ($0.109 against $0.81).
- Shared results
- 61
- GPT-5 Nano only
- 26
- Kimi K3 only
- 56
- Like-for-like categories
- 7 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
Only Kimi K3 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Kimi K3
Kimi K3 leads, 43.6 against 13.0.
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
Kimi K3
Kimi K3 leads, 92.9% against 63.4%.
Same board, both measured
Math
AIME
No call
Only GPT-5 Nano has a AIME result, 81.2%.
Directional only
Knowledge
MMLU Pro
Kimi K3
Kimi K3 leads, 88.0% against 76.1%.
Same board, both measured
Web design
Design Arena: websites
Kimi K3
Kimi K3 leads, 1335 against 1101.
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 Nano
GPT-5 Nano $0.0003, Kimi K3 $0.011 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
GPT-5 Nano
GPT-5 Nano $0.109, Kimi K3 $0.81.
Published attempt cost and pass rate
At a glance
- Coding index
- GPT-5 Nano not benchmarked, Kimi K3 62.3 from 6 benchmarks.
- Widest category
- Math, 39.9 points apart on average over 6 shared benchmarks.
- Widest single gap
- ProofBench: GPT-5 Nano 12.0% against Kimi K3 87.0%, 75.0 points apart on a 0 to 100 scale.
- Output price
- GPT-5 Nano $0.40 against Kimi K3 $15.00 per million output tokens, 37.5x apart.
- Context window
- GPT-5 Nano 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 Nano | Bars | Kimi K3 | Ties |
|---|---|---|---|---|
| Coding | 0 | 4 | ||
| Intelligence | 0 | 2 | ||
| Reasoning | 0 | 12 | ||
| Math | 0 | 6 | ||
| Knowledge | 0 | 10 | ||
| Web design | 0 | 6 | ||
| General | 0 | 21 | ||
| All shared boards | 0 | 61 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index04
| Benchmark | GPT-5 Nano | Kimi K3 | Leader |
|---|---|---|---|
| SWE-bench Verified | 34.8% | Not measured | Only GPT-5 Nano measured |
| LiveBench coding | Not measured | 59.3% | Only Kimi K3 measured |
| LMArena WebDev | Not measured | 1655 | Only Kimi K3 measured |
| AA Coding Index | Not measured | 76.2 | Only Kimi K3 measured |
| LiveCodeBench (Vals AI) | 70.2% | 87.2% | Kimi K3 |
| 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) | 78.9% | Not measured | Only GPT-5 Nano measured |
| SciCode | Not measured | 59.5% | Only Kimi K3 measured |
| Terminal-Bench Hard (Artificial Analysis run) | 17.4% | Not measured | Only GPT-5 Nano measured |
| Terminal-Bench | 21.8% | Not measured | Only GPT-5 Nano measured |
| FrontierCode | Not measured | 44.2% | Only Kimi K3 measured |
| FrontierSWE | Not measured | 25.9% | Only Kimi K3 measured |
| WeirdML | 38.1% | 82.6% | Kimi K3 |
| ALE-Bench | Not measured | 1524.5 | Only Kimi K3 measured |
| LMArena Text: coding | 1351 | 1508 | Kimi K3 |
| LMArena Text: software and IT | 1345 | 1499 | Kimi K3 |
| LMArena WebDev: React | Not measured | 1670 | Only Kimi K3 measured |
| LMArena WebDev: HTML | Not measured | 1644 | Only Kimi K3 measured |
| 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 index02
| Benchmark | GPT-5 Nano | Kimi K3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 13.0 | 43.6 | Kimi K3 |
| Epoch Capabilities Index | 139.2 | 157.9 | Kimi K3 |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index26 boards, none shared
| Benchmark | GPT-5 Nano | Kimi K3 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 50.0 | Only Kimi K3 measured |
| Design Arena: agents building web apps | Not measured | 1295 | 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 | 1269 | Only Kimi K3 measured |
| Design Arena: agents building Android apps | Not measured | 1250 | 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 | 36.5% | Not measured | Only GPT-5 Nano 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 |
| Berkeley Function Calling Leaderboard (BFCL) | 51.4% | Not measured | Only GPT-5 Nano measured |
| Neither model has a result on the other 15 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index012
| Benchmark | GPT-5 Nano | Kimi K3 | Leader |
|---|---|---|---|
| GPQA Diamond | 63.4% | 92.9% | Kimi K3 |
| LiveBench reasoning | Not measured | 90.7% | Only Kimi K3 measured |
| MMMU Pro (Vals AI) | 70.9% | 88.2% | Kimi K3 |
| GPQA Diamond (Artificial Analysis run) | 67.6% | 93.5% | Kimi K3 |
| Humanity's Last Exam (Artificial Analysis run) | 9.5% | 46.9% | Kimi K3 |
| GPQA Diamond (Epoch AI run) | 69.4% | 93.1% | Kimi K3 |
| ARC-AGI | 20.7% | 94.5% | Kimi K3 |
| ARC-AGI-2 | 2.6% | 60.4% | Kimi K3 |
| SimpleBench | Not measured | 60.7% | Only Kimi K3 measured |
| Chess puzzles | 22.0% | 37.0% | Kimi K3 |
| Mystery game puzzles | 9.0% | 26.0% | Kimi K3 |
| VPCT | 37.2% | Not measured | Only GPT-5 Nano measured |
| LMArena Text: hard prompts | 1328 | 1495 | Kimi K3 |
| LMArena Text: expert | 1321 | 1520 | Kimi K3 |
| LMArena Text: hard prompts in English | 1338 | 1496 | Kimi K3 |
| LMArena Vision: diagrams | 1141 | Not measured | Only GPT-5 Nano measured |
| LMArena Vision: homework | 1157 | Not measured | Only GPT-5 Nano measured |
| Kagi LLM Benchmark | 62.2% | Not measured | Only GPT-5 Nano measured |
| Neither model has a result on the other 4 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | GPT-5 Nano | Kimi K3 | Leader |
|---|---|---|---|
| AIME | 81.2% | Not measured | Only GPT-5 Nano measured |
| MATH 500 (Vals AI) | 93.8% | Not measured | Only GPT-5 Nano measured |
| MGSM (Vals AI) | 89.3% | Not measured | Only GPT-5 Nano measured |
| AA Math Index | 83.7 | Not measured | Only GPT-5 Nano measured |
| AIME 2025 (Artificial Analysis run) | 83.7% | Not measured | Only GPT-5 Nano measured |
| OTIS Mock AIME | 81.1% | 97.2% | Kimi K3 |
| FrontierMath, tiers 1 to 3 | 20.0% | 72.2% | Kimi K3 |
| FrontierMath, tier 4 | 2.4% | 39.0% | Kimi K3 |
| ProofBench | 12.0% | 87.0% | Kimi K3 |
| MATH level 5 | 95.2% | Not measured | Only GPT-5 Nano measured |
| LMArena Text: math | 1317 | 1494 | Kimi K3 |
| LMArena Text: mathematical work | 1326 | 1505 | Kimi K3 |
| Neither model has a result on the other 1 board here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index010
| Benchmark | GPT-5 Nano | Kimi K3 | Leader |
|---|---|---|---|
| MMLU Pro | 76.1% | 88.0% | Kimi K3 |
| LegalBench (Vals AI) | 50.1% | 86.2% | Kimi K3 |
| CaseLaw (Vals AI) | 52.6% | Not measured | Only GPT-5 Nano measured |
| CorpFin (Vals AI) | Not measured | 71.6% | Only Kimi K3 measured |
| TaxEval (Vals AI) | 67.4% | 75.7% | Kimi K3 |
| MortgageTax (Vals AI) | 53.6% | 66.3% | Kimi K3 |
| MedQA (Vals AI) | 93.3% | Not measured | Only GPT-5 Nano measured |
| MedCode (Vals AI) | 30.4% | 49.4% | Kimi K3 |
| MMLU Pro (Artificial Analysis run) | 78.0% | Not measured | Only GPT-5 Nano measured |
| SimpleQA Verified | 11.7% | 50.6% | Kimi K3 |
| LMArena Text: science | 1318 | 1508 | Kimi K3 |
| LMArena Text: medicine and healthcare | 1335 | 1489 | Kimi K3 |
| LMArena Text: legal and government | 1298 | 1503 | Kimi K3 |
| LMArena Text: business and finance | 1311 | 1470 | Kimi K3 |
| Neither model has a result on the other 4 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | GPT-5 Nano | Kimi K3 | Leader |
|---|---|---|---|
| Design Arena: websites | 1101 | 1335 | Kimi K3 |
| Design Arena: UI components | 1067 | 1344 | Kimi K3 |
| Design Arena: game dev | 1045 | 1359 | Kimi K3 |
| Design Arena: data viz | 1056 | 1351 | Kimi K3 |
| Design Arena: 3D | 966 | 1388 | Kimi K3 |
| Design Arena: all code categories | 1084 | 1360 | Kimi K3 |
| Design Arena: SVG | Not measured | 1302 | Only Kimi K3 measured |
| LiveBench design | Not measured | 77.2% | Only Kimi K3 measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index021
| Benchmark | GPT-5 Nano | 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) | 30.4% | 52.8% | Kimi K3 |
| MedScribe (Vals AI) | 72.9% | 88.0% | Kimi K3 |
| Vals Multimodal Index | Not measured | 73.4% | Only Kimi K3 measured |
| IFBench | 67.6% | Not measured | Only GPT-5 Nano measured |
| Long context reasoning (AA-LCR) | 45.0% | 88.7% | Kimi K3 |
| DTBench | 62.7% | 91.2% | Kimi K3 |
| LMCA | 7.9% | 52.7% | Kimi K3 |
| Fiction.LiveBench | 44.4% | Not measured | Only GPT-5 Nano measured |
| Surface Evolver Bench | Not measured | 95.0% | Only Kimi K3 measured |
| Furniture assembly | Not measured | 34.2% | Only Kimi K3 measured |
| LMArena Text | 1320 | 1476 | Kimi K3 |
| LMArena Text: instruction following | 1306 | 1485 | Kimi K3 |
| LMArena Text: creative writing | 1249 | 1457 | Kimi K3 |
| LMArena Vision | 1159 | Not measured | Only GPT-5 Nano measured |
| LMArena Text: English | 1321 | 1481 | Kimi K3 |
| LMArena Text: non-English | 1313 | 1466 | Kimi K3 |
| LMArena Text: Chinese | 1356 | 1529 | Kimi K3 |
| LMArena Text: German | 1327 | 1490 | Kimi K3 |
| LMArena Text: Japanese | 1227 | 1494 | Kimi K3 |
| LMArena Text: Korean | 1269 | 1460 | Kimi K3 |
| LMArena Text: French | Not measured | 1492 | Only Kimi K3 measured |
| LMArena Text: Spanish | 1360 | 1472 | Kimi K3 |
| LMArena Text: Russian | 1296 | 1485 | Kimi K3 |
| LMArena Text: Polish | 1314 | 1458 | Kimi K3 |
| LMArena Text: multi-turn | 1311 | 1489 | Kimi K3 |
| LMArena Text: longer queries | 1312 | 1494 | Kimi K3 |
| LMArena Text: writing and language | 1283 | 1471 | Kimi K3 |
| LMArena Text: entertainment and media | 1268 | 1453 | Kimi K3 |
| LMArena Vision: English | 1170 | Not measured | Only GPT-5 Nano measured |
| LMArena Vision: Chinese | 1176 | Not measured | Only GPT-5 Nano measured |
| LMArena Vision: reading text | 1152 | Not measured | Only GPT-5 Nano measured |
| LMArena Vision: humor | 1110 | Not measured | Only GPT-5 Nano measured |
| Neither model has a result on the other 11 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-5 Nano | 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 Nano costs less
Repository review
50K input + 3K output tokens
GPT-5 Nano costs less
Agent loop
200K input + 10K output tokens
GPT-5 Nano 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 Nano | MoonshotAI Kimi K3 |
|---|---|---|
| Maker | OpenAI | Moonshot AI |
| Weights | No public weights listed | Open weights |
| Released | August 7, 2025 | July 16, 2026 |
| Context window | 400K | 1.05M |
| Input $/Mtok | $0.05 | $3.00 |
| Output $/Mtok | $0.40 | $15.00 |
| Coding index | Not benchmarked | 62.3 |
| Independent measurements behind it | 0 | 6 |
| Cost per solved task | $0.109 | $0.81 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-5 Nano better than Kimi K3 for coding?
Only Kimi K3 has a coding score, 62.3 on the Vibe Coding Index; GPT-5 Nano has none, so the two cannot be ranked on coding. Pick GPT-5 Nano for output tokens 37.5x cheaper ($0.40 vs $15.00 per million) and a lower cost per solved task ($0.109 against $0.81).
Which is cheaper, GPT-5 Nano or Kimi K3?
GPT-5 Nano costs $0.05 per million input tokens and $0.40 per million output tokens; Kimi K3 costs $3.00 and $15.00. Per solved SWE-bench Verified task, GPT-5 Nano costs $0.109 and Kimi K3 $0.81.
Which has the bigger context window, GPT-5 Nano or Kimi K3?
Kimi K3, with 1.05M tokens against 400K.
How many benchmarks is the GPT-5 Nano vs Kimi K3 comparison based on?
61 benchmarks have a result for both models as of October 21, 2026. GPT-5 Nano's coding index rests on 0 independent benchmarks and Kimi K3's on 6. Where only one model has a result, the page says so instead of naming a winner.