Model comparison
GPT-5.6 Luna vs Grok 4.5
GPT-5.6 Luna and Grok 4.5 score almost the same on the Noometry Index (54.6 vs 55.0), so choose on price, context window or the category you care about most.
Last verified . 48 shared benchmarks.
Summary
- They share 48 benchmarks with published results for both. GPT-5.6 Luna scores higher in 4 categories and Grok 4.5 in 6 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.6 Luna leads 77.7 to 60.9.
- The biggest single-benchmark swing is FrontierMath Tier 4: 61% for GPT-5.6 Luna and 24.4% for Grok 4.5.
- GPT-5.6 Luna is cheaper at $0.20 / $1.20 per million input/output tokens, against $2 / $6 for Grok 4.5.
- GPT-5.6 Luna accepts more context: 1.05M tokens versus 500K.
Side by side
| GPT-5.6 Luna | Grok 4.5 | |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 54.6 | 55.0 |
| Released | 2026-07-09 | 2026-07-08 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 500K |
| Max output | 128K | 500K |
| Input $ / M tokens | $0.20 | $2 |
| Output $ / M tokens | $1.20 | $6 |
| Results tracked | 52 | 52 |
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Category by category
Coding GPT-5.6 Luna leads
GPT-5.6 Luna: 54.5 (#28), Grok 4.5: 52.2 (#35)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| DeepSWE | 67.2% | 53.8% |
| FrontierCode | 39.8% | 42.4% |
| LMArena WebDev | 1519 | 1553 |
| SciCode | 53.6% | 54.1% |
| WeirdML | 60.9% | 46.4% |
| LMArena Coding | 1466 | 1474 |
| ALE-Bench | 1,667 | 1,309 |
| CursorBench | 35.9% | — |
Agentic & Tool Use Grok 4.5 leads
GPT-5.6 Luna: 34.4 (#45), Grok 4.5: 44.4 (#17)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| APEX-Agents | 43% | 56.2% |
| GDP.pdf | 22.7% | 14% |
| Vending-Bench 2 | 4,095 | 3,887 |
| τ²-bench Banking | — | 47.9% |
| PostTrainBench | — | 23.4% |
| BALROG | 45.6% | — |
| GBAEval | — | 65.4% |
| LMArena Search | — | 1213 |
Reasoning Grok 4.5 leads
GPT-5.6 Luna: 47.6 (#43), Grok 4.5: 56.1 (#25)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| ARC-AGI-2 | 59.5% | 52.6% |
| SimpleBench | 46.8% | 70% |
| Kagi LLM Benchmark | 49.1% | 83.5% |
| NYT Connections (extended) | 69.4% | 79.9% |
| ARC-AGI-1 | 88% | 87.2% |
| CritPt | 20.6% | 15.4% |
| Chess Puzzles | 40% | 36% |
| LMArena Hard Prompts | 1451 | 1462 |
| DTBench | 89.1% | 96.5% |
| LMCA | 48.5% | 45.2% |
| Surface Evolver Bench | 61.9% | 74.4% |
| Epoch Capabilities Index | 156.39 | 153.92 |
| Mystery Game Puzzles | 21% | — |
Math GPT-5.6 Luna leads
GPT-5.6 Luna: 77.7 (#14), Grok 4.5: 60.9 (#35)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 82.1% | 57.2% |
| FrontierMath Tier 4 | 61% | 24.4% |
| OTIS Mock AIME 2024-2025 | 98.3% | 97.8% |
| ProofBench | 60% | 31% |
| LMArena Math | 1458 | 1459 |
Knowledge Grok 4.5 leads
GPT-5.6 Luna: 58.5 (#34), Grok 4.5: 62.3 (#24)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| GPQA Diamond | 91.6% | 93.4% |
| SimpleQA Verified | 41% | 48.3% |
| LMArena Expert | 1478 | 1466 |
Multimodal GPT-5.6 Luna leads
GPT-5.6 Luna: 42.7 (#28), Grok 4.5: 37.6 (#72)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| LMArena Vision | 1258 | 1288 |
| Blueprint-Bench 2 | 22.6% | 27.3% |
| Furniture Assembly | 42.5% | 22.5% |
| LMArena Document | 1457 | 1452 |
Multilingual Grok 4.5 leads
GPT-5.6 Luna: 52.8 (#78), Grok 4.5: 54.4 (#42)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| LMArena Non-English | 1417 | 1440 |
| LMArena Chinese | 1470 | 1496 |
| LMArena French | 1456 | 1456 |
| LMArena German | 1454 | 1446 |
| LMArena Japanese | 1411 | 1428 |
| LMArena Korean | 1415 | 1404 |
| LMArena Russian | 1428 | 1448 |
| LMArena Spanish | 1448 | 1450 |
Instruction Following Too close to call
GPT-5.6 Luna: 75.6 (#57), Grok 4.5: 76.0 (#48)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| LMArena Instruction Following | 1437 | 1446 |
Long Context Too close to call
GPT-5.6 Luna: 43.9 (#82), Grok 4.5: 44.8 (#56)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| LMArena Longer Query | 1436 | 1463 |
Writing & Preference GPT-5.6 Luna leads
GPT-5.6 Luna: 68.0 (#29), Grok 4.5: 65.8 (#42)
| Benchmark | GPT-5.6 Luna | Grok 4.5 |
|---|---|---|
| LMArena Text | 1431 | 1448 |
| LMArena Creative Writing | 1396 | 1442 |
| EQ-Bench Creative Writing | 1829 | 1579 |
| LMArena Multi-Turn | 1434 | 1456 |
| EQ-Bench 4 | 1156 | — |
Frequently asked questions
Is GPT-5.6 Luna better than Grok 4.5?
GPT-5.6 Luna and Grok 4.5 score almost the same on the Noometry Index (54.6 vs 55.0), so choose on price, context window or the category you care about most.
Which is cheaper, GPT-5.6 Luna or Grok 4.5?
GPT-5.6 Luna is cheaper. It lists at $0.20 per million input tokens and $1.20 per million output tokens; Grok 4.5 lists at $2 and $6.
Is GPT-5.6 Luna or Grok 4.5 better for coding?
GPT-5.6 Luna scores higher on coding benchmarks: 54.5 versus 52.2 in the Noometry coding category.
Which has the bigger context window?
GPT-5.6 Luna does, with 1.05M tokens against 500K.
How many benchmarks do GPT-5.6 Luna and Grok 4.5 share?
48 benchmarks have published results for both models. GPT-5.6 Luna has 52 scored results on Noometry and Grok 4.5 has 52.