gpt-oss-120b vs Kimi K3
Kimi K3 leads gpt-oss-120b on the Artificial Analysis Intelligence Index, 43.6 to 11.6, and gpt-oss-120b costs 30.0x less per output token ($0.50 vs $15.00 per million). Updated October 21, 2026; 60 benchmarks have a result for both.
gpt-oss-120b or Kimi K3: which to pick
Only Kimi K3 has a coding score, 62.3 on the Vibe Coding Index; gpt-oss-120b has none, so the two cannot be ranked on coding.
Pick gpt-oss-120b for output tokens 30.0x cheaper ($0.50 vs $15.00 per million) and a lower cost per solved task ($0.51 against $0.81).
- Shared results
- 60
- gpt-oss-120b only
- 21
- Kimi K3 only
- 57
- Like-for-like categories
- 8 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 11.6.
Same board, both measured
Agentic work
AA Agentic Index
Kimi K3
Kimi K3 leads, 50.0 against 3.7.
Same board, both measured
Reasoning
GPQA Diamond
Kimi K3
Kimi K3 leads, 92.9% against 78.5%.
Same board, both measured
Math
AIME
No call
Only gpt-oss-120b has a AIME result, 92.6%.
Directional only
Knowledge
MMLU Pro
Kimi K3
Kimi K3 leads, 88.0% against 79.2%.
Same board, both measured
Web design
Design Arena: websites
Kimi K3
Kimi K3 leads, 1335 against 968.
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 131K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
gpt-oss-120b
gpt-oss-120b $0.0003, Kimi K3 $0.011 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
gpt-oss-120b
gpt-oss-120b $0.51, Kimi K3 $0.81.
Published attempt cost and pass rate
At a glance
- Coding index
- gpt-oss-120b not benchmarked, Kimi K3 62.3 from 6 benchmarks.
- Widest category
- Web design, 50.0 points apart on average over 6 shared benchmarks.
- Widest single gap
- Surface Evolver Bench: gpt-oss-120b 25.0% against Kimi K3 95.0%, 70.0 points apart on a 0 to 100 scale.
- Output price
- gpt-oss-120b $0.50 against Kimi K3 $15.00 per million output tokens, 30.0x apart.
- Context window
- gpt-oss-120b takes 131K 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-oss-120b | Bars | Kimi K3 | Ties |
|---|---|---|---|---|
| Coding | 0 | 8 | ||
| Intelligence | 0 | 2 | ||
| Agentic work | 0 | 3 | ||
| Reasoning | 0 | 9 | ||
| Math | 0 | 3 | ||
| Knowledge | 0 | 8 | ||
| Web design | 0 | 6 | ||
| General | 0 | 21 | ||
| All shared boards | 0 | 60 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index08
| Benchmark | gpt-oss-120b | Kimi K3 | Leader |
|---|---|---|---|
| Aider polyglot | 41.8% | Not measured | Only gpt-oss-120b measured |
| SWE-bench Verified | 26.0% | Not measured | Only gpt-oss-120b measured |
| LiveBench coding | Not measured | 59.3% | Only Kimi K3 measured |
| LMArena WebDev | Not measured | 1655 | Only Kimi K3 measured |
| AA Coding Index | 30.4 | 76.2 | Kimi K3 |
| LiveCodeBench (Vals AI) | 83.2% | 87.2% | Kimi K3 |
| SWE-bench Verified (Vals AI) | 33.6% | 93.4% | Kimi K3 |
| 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) | 87.8% | Not measured | Only gpt-oss-120b measured |
| SciCode | 34.0% | 59.5% | Kimi K3 |
| Terminal-Bench Hard (Artificial Analysis run) | 23.5% | Not measured | Only gpt-oss-120b measured |
| Terminal-Bench | 18.7% | Not measured | Only gpt-oss-120b measured |
| FrontierCode | Not measured | 44.2% | Only Kimi K3 measured |
| FrontierSWE | Not measured | 25.9% | Only Kimi K3 measured |
| WeirdML | 48.2% | 82.6% | Kimi K3 |
| ALE-Bench | 575.6 | 1524.5 | Kimi K3 |
| LMArena Text: coding | 1379 | 1508 | Kimi K3 |
| LMArena Text: software and IT | 1387 | 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 |
| SciCode | 7.7% | Not measured | Only gpt-oss-120b measured |
| Neither model has a result on the other 9 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | gpt-oss-120b | Kimi K3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 11.6 | 43.6 | Kimi K3 |
| Epoch Capabilities Index | 139.8 | 157.9 | Kimi K3 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | gpt-oss-120b | Kimi K3 | Leader |
|---|---|---|---|
| AA Agentic Index | 3.7 | 50.0 | Kimi K3 |
| 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 | 65.8% | Not measured | Only gpt-oss-120b measured |
| APEX-Agents | 4.4% | 47.8% | Kimi K3 |
| METR time horizons | 56.6% | Not measured | Only gpt-oss-120b measured |
| PostTrainBench | Not measured | 32.0% | Only Kimi K3 measured |
| Vending-Bench 2 | -$22 | $5,165 | Kimi K3 |
| BrowseComp-Plus | 67.0% | Not measured | Only gpt-oss-120b measured |
| Neither model has a result on the other 14 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index09
| Benchmark | gpt-oss-120b | Kimi K3 | Leader |
|---|---|---|---|
| GPQA Diamond | 78.5% | 92.9% | Kimi K3 |
| 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) | 78.2% | 93.5% | Kimi K3 |
| Humanity's Last Exam (Artificial Analysis run) | 19.6% | 46.9% | Kimi K3 |
| GPQA Diamond (Epoch AI run) | 75.8% | 93.1% | Kimi K3 |
| ARC-AGI | Not measured | 94.5% | Only Kimi K3 measured |
| ARC-AGI-2 | Not measured | 60.4% | Only Kimi K3 measured |
| SimpleBench | 22.1% | 60.7% | Kimi K3 |
| Chess puzzles | Not measured | 37.0% | Only Kimi K3 measured |
| Mystery game puzzles | 2.0% | 26.0% | Kimi K3 |
| LMArena Text: hard prompts | 1364 | 1495 | Kimi K3 |
| LMArena Text: expert | 1356 | 1520 | Kimi K3 |
| LMArena Text: hard prompts in English | 1368 | 1496 | Kimi K3 |
| Kagi LLM Benchmark | 58.6% | Not measured | Only gpt-oss-120b measured |
| Neither model has a result on the other 7 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | gpt-oss-120b | Kimi K3 | Leader |
|---|---|---|---|
| AIME | 92.6% | Not measured | Only gpt-oss-120b measured |
| MATH 500 (Vals AI) | 94.8% | Not measured | Only gpt-oss-120b measured |
| MGSM (Vals AI) | 92.0% | Not measured | Only gpt-oss-120b measured |
| AA Math Index | 93.4 | Not measured | Only gpt-oss-120b measured |
| AIME 2025 (Artificial Analysis run) | 93.4% | Not measured | Only gpt-oss-120b measured |
| OTIS Mock AIME | 88.9% | 97.2% | Kimi K3 |
| 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 | 1389 | 1494 | Kimi K3 |
| LMArena Text: mathematical work | 1386 | 1505 | Kimi K3 |
| Neither model has a result on the other 2 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index08
| Benchmark | gpt-oss-120b | Kimi K3 | Leader |
|---|---|---|---|
| MMLU Pro | 79.2% | 88.0% | Kimi K3 |
| LegalBench (Vals AI) | 75.9% | 86.2% | Kimi K3 |
| CaseLaw (Vals AI) | 48.8% | Not measured | Only gpt-oss-120b measured |
| CorpFin (Vals AI) | 58.2% | 71.6% | Kimi K3 |
| TaxEval (Vals AI) | 71.6% | 75.7% | Kimi K3 |
| MortgageTax (Vals AI) | Not measured | 66.3% | Only Kimi K3 measured |
| MedQA (Vals AI) | 91.4% | Not measured | Only gpt-oss-120b measured |
| MedCode (Vals AI) | Not measured | 49.4% | Only Kimi K3 measured |
| MMLU Pro (Artificial Analysis run) | 80.8% | Not measured | Only gpt-oss-120b measured |
| SimpleQA Verified | Not measured | 50.6% | Only Kimi K3 measured |
| LMArena Text: science | 1382 | 1508 | Kimi K3 |
| LMArena Text: medicine and healthcare | 1388 | 1489 | Kimi K3 |
| LMArena Text: legal and government | 1355 | 1503 | Kimi K3 |
| LMArena Text: business and finance | 1359 | 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-oss-120b | Kimi K3 | Leader |
|---|---|---|---|
| Design Arena: websites | 968 | 1335 | Kimi K3 |
| Design Arena: UI components | 927 | 1344 | Kimi K3 |
| Design Arena: game dev | 992 | 1359 | Kimi K3 |
| Design Arena: data viz | 987 | 1351 | Kimi K3 |
| Design Arena: 3D | 901 | 1388 | Kimi K3 |
| Design Arena: all code categories | 963 | 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-oss-120b | 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 | 69.0% | Not measured | Only gpt-oss-120b measured |
| Long context reasoning (AA-LCR) | 52.0% | 88.7% | Kimi K3 |
| DTBench | 76.3% | 91.2% | Kimi K3 |
| LMCA | 22.1% | 52.7% | Kimi K3 |
| Fiction.LiveBench | 44.4% | Not measured | Only gpt-oss-120b measured |
| Creative writing (Lech Mazur) | 77.1% | Not measured | Only gpt-oss-120b measured |
| Surface Evolver Bench | 25.0% | 95.0% | Kimi K3 |
| Furniture assembly | Not measured | 34.2% | Only Kimi K3 measured |
| LMArena Text | 1366 | 1476 | Kimi K3 |
| LMArena Text: instruction following | 1318 | 1485 | Kimi K3 |
| LMArena Text: creative writing | 1274 | 1457 | Kimi K3 |
| LMArena Text: English | 1375 | 1481 | Kimi K3 |
| LMArena Text: non-English | 1351 | 1466 | Kimi K3 |
| LMArena Text: Chinese | 1385 | 1529 | Kimi K3 |
| LMArena Text: German | 1353 | 1490 | Kimi K3 |
| LMArena Text: Japanese | 1331 | 1494 | Kimi K3 |
| LMArena Text: Korean | 1282 | 1460 | Kimi K3 |
| LMArena Text: French | 1370 | 1492 | Kimi K3 |
| LMArena Text: Spanish | 1389 | 1472 | Kimi K3 |
| LMArena Text: Russian | 1343 | 1485 | Kimi K3 |
| LMArena Text: Polish | 1353 | 1458 | Kimi K3 |
| LMArena Text: multi-turn | 1340 | 1489 | Kimi K3 |
| LMArena Text: longer queries | 1319 | 1494 | Kimi K3 |
| LMArena Text: writing and language | 1306 | 1471 | Kimi K3 |
| LMArena Text: entertainment and media | 1292 | 1453 | Kimi K3 |
| Neither model has a result on the other 15 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | gpt-oss-120b | 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-oss-120b costs less
Repository review
50K input + 3K output tokens
gpt-oss-120b costs less
Agent loop
200K input + 10K output tokens
gpt-oss-120b 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-oss-120b | MoonshotAI Kimi K3 |
|---|---|---|
| Maker | OpenAI | Moonshot AI |
| Weights | Open weights | Open weights |
| Released | August 5, 2025 | July 16, 2026 |
| Context window | 131K | 1.05M |
| Input $/Mtok | $0.10 | $3.00 |
| Output $/Mtok | $0.50 | $15.00 |
| Coding index | Not benchmarked | 62.3 |
| Independent measurements behind it | 1 | 6 |
| Cost per solved task | $0.51 | $0.81 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is gpt-oss-120b better than Kimi K3 for coding?
Only Kimi K3 has a coding score, 62.3 on the Vibe Coding Index; gpt-oss-120b has none, so the two cannot be ranked on coding. Pick gpt-oss-120b for output tokens 30.0x cheaper ($0.50 vs $15.00 per million) and a lower cost per solved task ($0.51 against $0.81).
Which is cheaper, gpt-oss-120b or Kimi K3?
gpt-oss-120b costs $0.10 per million input tokens and $0.50 per million output tokens; Kimi K3 costs $3.00 and $15.00. Per solved SWE-bench Verified task, gpt-oss-120b costs $0.51 and Kimi K3 $0.81.
Which has the bigger context window, gpt-oss-120b or Kimi K3?
Kimi K3, with 1.05M tokens against 131K.
How many benchmarks is the gpt-oss-120b vs Kimi K3 comparison based on?
60 benchmarks have a result for both models as of October 21, 2026. gpt-oss-120b's coding index rests on 1 independent benchmark and Kimi K3's on 6. Where only one model has a result, the page says so instead of naming a winner.