Model comparison
GPT-5.6 Luna vs Kimi K3
Kimi K3 is the stronger model overall, scoring 59.5 to 54.6 on the Noometry Index. GPT-5.6 Luna costs 13× less per token, which makes it the better buy when Kimi K3's lead doesn't matter for your workload.
Last verified . 47 shared benchmarks.
Summary
- They share 47 benchmarks with published results for both. GPT-5.6 Luna scores higher in 2 categories and Kimi K3 in 8 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Kimi K3 leads 63.0 to 47.6.
- The biggest single-benchmark swing is Surface Evolver Bench: 61.9% for GPT-5.6 Luna and 95% for Kimi K3.
- GPT-5.6 Luna is cheaper at $0.20 / $1.20 per million input/output tokens, against $3 / $15 for Kimi K3.
- GPT-5.6 Luna accepts more context: 1.05M tokens versus 1.05M.
- Kimi K3 has downloadable open weights; the other is API-only.
Side by side
| GPT-5.6 Luna | Kimi K3 | |
|---|---|---|
| Provider | OpenAI | Moonshot AI |
| Noometry Index | 54.6 | 59.5 |
| Released | 2026-07-09 | 2026-07-16 |
| Weights | Proprietary | Open |
| Context window | 1.05M | 1.05M |
| Max output | 128K | 1.05M |
| Input $ / M tokens | $0.20 | $3 |
| Output $ / M tokens | $1.20 | $15 |
| Results tracked | 52 | 53 |
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Category by category
Coding Kimi K3 leads
GPT-5.6 Luna: 54.5 (#28), Kimi K3: 61.0 (#10)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| DeepSWE | 67.2% | 68.5% |
| FrontierCode | 39.8% | 44.2% |
| LMArena WebDev | 1519 | 1654 |
| SciCode | 53.6% | 59.5% |
| WeirdML | 60.9% | 82.6% |
| LMArena Coding | 1466 | 1508 |
| ALE-Bench | 1,667 | 1,524 |
| CursorBench | 35.9% | — |
| FrontierSWE | — | 25.9% |
Agentic & Tool Use Kimi K3 leads
GPT-5.6 Luna: 34.4 (#45), Kimi K3: 41.8 (#20)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| APEX-Agents | 43% | 50.6% |
| GDP.pdf | 22.7% | 19% |
| Vending-Bench 2 | 4,095 | 5,165 |
| τ²-bench Banking | — | 37.1% |
| PostTrainBench | — | 32% |
| BALROG | 45.6% | — |
| GBAEval | — | 48.3% |
Reasoning Kimi K3 leads
GPT-5.6 Luna: 47.6 (#43), Kimi K3: 63.0 (#17)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| ARC-AGI-2 | 59.5% | 60.4% |
| SimpleBench | 46.8% | 60.7% |
| NYT Connections (extended) | 69.4% | 93.6% |
| ARC-AGI-1 | 88% | 94.5% |
| CritPt | 20.6% | 23.4% |
| Chess Puzzles | 40% | 39% |
| LMArena Hard Prompts | 1451 | 1496 |
| Mystery Game Puzzles | 21% | 26% |
| DTBench | 89.1% | 91.2% |
| LMCA | 48.5% | 52.7% |
| Surface Evolver Bench | 61.9% | 95% |
| Epoch Capabilities Index | 156.39 | 157.45 |
| Kagi LLM Benchmark | 49.1% | — |
| ForecastBench | — | 61.1 |
Math GPT-5.6 Luna leads
GPT-5.6 Luna: 77.7 (#14), Kimi K3: 74.2 (#16)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 82.1% | 72.2% |
| FrontierMath Tier 4 | 61% | 39% |
| OTIS Mock AIME 2024-2025 | 98.3% | 97.2% |
| ProofBench | 60% | 87% |
| LMArena Math | 1458 | 1491 |
| MathArena Final-Answer Competitions | — | 87.8% |
Knowledge Kimi K3 leads
GPT-5.6 Luna: 58.5 (#34), Kimi K3: 63.2 (#21)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| GPQA Diamond | 91.6% | 93.1% |
| SimpleQA Verified | 41% | 50.6% |
| LMArena Expert | 1478 | 1521 |
Multimodal GPT-5.6 Luna leads
GPT-5.6 Luna: 42.7 (#28), Kimi K3: 37.8 (#70)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| Blueprint-Bench 2 | 22.6% | 29.5% |
| Furniture Assembly | 42.5% | 34.2% |
| LMArena Vision | 1258 | — |
| LMArena Document | 1457 | — |
Multilingual Kimi K3 leads
GPT-5.6 Luna: 52.8 (#78), Kimi K3: 56.3 (#21)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| LMArena Non-English | 1417 | 1466 |
| LMArena Chinese | 1470 | 1529 |
| LMArena French | 1456 | 1491 |
| LMArena German | 1454 | 1488 |
| LMArena Japanese | 1411 | 1487 |
| LMArena Korean | 1415 | 1458 |
| LMArena Russian | 1428 | 1482 |
| LMArena Spanish | 1448 | 1472 |
Instruction Following Kimi K3 leads
GPT-5.6 Luna: 75.6 (#57), Kimi K3: 77.7 (#14)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| LMArena Instruction Following | 1437 | 1483 |
Long Context Kimi K3 leads
GPT-5.6 Luna: 43.9 (#82), Kimi K3: 45.8 (#29)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| LMArena Longer Query | 1436 | 1494 |
Writing & Preference Kimi K3 leads
GPT-5.6 Luna: 68.0 (#29), Kimi K3: 76.6 (#4)
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| LMArena Text | 1431 | 1476 |
| LMArena Creative Writing | 1396 | 1454 |
| EQ-Bench Creative Writing | 1829 | 2082 |
| EQ-Bench 4 | 1156 | 1339 |
| LMArena Multi-Turn | 1434 | 1488 |
Frequently asked questions
Is GPT-5.6 Luna better than Kimi K3?
Kimi K3 is the stronger model overall, scoring 59.5 to 54.6 on the Noometry Index. GPT-5.6 Luna costs 13× less per token, which makes it the better buy when Kimi K3's lead doesn't matter for your workload.
Which is cheaper, GPT-5.6 Luna or Kimi K3?
GPT-5.6 Luna is cheaper. It lists at $0.20 per million input tokens and $1.20 per million output tokens; Kimi K3 lists at $3 and $15.
Is GPT-5.6 Luna or Kimi K3 better for coding?
Kimi K3 scores higher on coding benchmarks: 61.0 versus 54.5 in the Noometry coding category.
Which has the bigger context window?
GPT-5.6 Luna does, with 1.05M tokens against 1.05M.
How many benchmarks do GPT-5.6 Luna and Kimi K3 share?
47 benchmarks have published results for both models. GPT-5.6 Luna has 52 scored results on Noometry and Kimi K3 has 53.