Model comparison
GPT-6 Luna vs Grok 4.20 (Non-Reasoning)
Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.5 to 45.1 on the Noometry Index. GPT-6 Luna costs 7.8× less per token, which makes it the better buy when Grok 4.20 (Non-Reasoning)'s lead doesn't matter for your workload.
Last verified . 15 shared benchmarks.
Summary
- They share 15 benchmarks with published results for both. GPT-6 Luna scores higher in 2 categories and Grok 4.20 (Non-Reasoning) in 7 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.20 (Non-Reasoning) leads 52.2 to 31.7.
- The biggest single-benchmark swing is NYT Connections (extended): 68.7% for GPT-6 Luna and 85.4% for Grok 4.20 (Non-Reasoning).
- GPT-6 Luna is cheaper at $0.10 / $0.50 per million input/output tokens, against $1.25 / $2.50 for Grok 4.20 (Non-Reasoning).
- GPT-6 Luna accepts more context: 1.05M tokens versus 1M.
Side by side
| GPT-6 Luna | Grok 4.20 (Non-Reasoning) | |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 45.1 | 48.5 |
| Released | 2026-09-22 | 2026-02-17 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 1M |
| Max output | 128K | 30K |
| Input $ / M tokens | $0.10 | $1.25 |
| Output $ / M tokens | $0.50 | $2.50 |
| Results tracked | 18 | 46 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding GPT-6 Luna leads
GPT-6 Luna: 54.7 (#24), Grok 4.20 (Non-Reasoning): 41.8 (#104)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena WebDev | 1583 | 1374 |
| LMArena Coding | 1448 | 1458 |
| DeepSWE | 66.6% | — |
| FrontierCode | 42.4% | — |
| WeirdML | — | 52.3% |
| ALE-Bench | — | 1,150 |
Agentic & Tool Use Not comparable
GPT-6 Luna: —, Grok 4.20 (Non-Reasoning): 34.3 (#43)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| Terminal-Bench | — | 57.3% |
| τ²-bench Banking | — | 18% |
| LMArena Search | — | 1189 |
| Vending-Bench 2 | — | 4,663 |
Reasoning Grok 4.20 (Non-Reasoning) leads
GPT-6 Luna: 31.7 (#68), Grok 4.20 (Non-Reasoning): 52.2 (#30)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| NYT Connections (extended) | 68.7% | 85.4% |
| LMArena Hard Prompts | 1415 | 1451 |
| ARC-AGI-2 | — | 65.1% |
| Kagi LLM Benchmark | — | 75% |
| ARC-AGI-1 | — | 89.5% |
| Chess Puzzles | — | 24% |
| Thematic Generalization | — | 63.8% |
| DTBench | — | 90.1% |
| LMCA | — | 38.7% |
| Epoch Capabilities Index | — | 152.01 |
| ForecastBench | — | 61.4 |
Math Grok 4.20 (Non-Reasoning) leads
GPT-6 Luna: 35.6 (#140), Grok 4.20 (Non-Reasoning): 48.0 (#54)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Math | 1396 | 1455 |
| FrontierMath (Tiers 1-3) | — | 44.9% |
| FrontierMath Tier 4 | — | 17.1% |
| OTIS Mock AIME 2024-2025 | — | 92.2% |
| ProofBench | — | 14% |
Knowledge Grok 4.20 (Non-Reasoning) leads
GPT-6 Luna: 40.1 (#110), Grok 4.20 (Non-Reasoning): 52.8 (#54)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Expert | 1458 | 1440 |
| GPQA Diamond | — | 89.3% |
| SimpleQA Verified | — | 30.2% |
Multimodal GPT-6 Luna leads
GPT-6 Luna: 42.0 (#27), Grok 4.20 (Non-Reasoning): 33.2 (#88)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Vision | — | 1263 |
| Blueprint-Bench 2 | — | 0% |
| Furniture Assembly | 44.2% | — |
| LMArena Document | — | 1416 |
Multilingual Grok 4.20 (Non-Reasoning) leads
GPT-6 Luna: 51.0 (#111), Grok 4.20 (Non-Reasoning): 54.7 (#38)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Non-English | 1390 | 1440 |
| LMArena Chinese | 1425 | 1481 |
| LMArena Russian | 1392 | 1457 |
| LMArena Spanish | 1416 | 1442 |
| LMArena French | — | 1477 |
| LMArena German | — | 1463 |
| LMArena Japanese | — | 1450 |
| LMArena Korean | — | 1417 |
Instruction Following Too close to call
GPT-6 Luna: 74.7 (#85), Grok 4.20 (Non-Reasoning): 75.0 (#79)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Instruction Following | 1414 | 1420 |
Long Context Grok 4.20 (Non-Reasoning) leads
GPT-6 Luna: 43.3 (#95), Grok 4.20 (Non-Reasoning): 45.4 (#33)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Longer Query | 1417 | 1436 |
| CL-bench | — | 22.2% |
| CL-bench Life | — | 11.9% |
Writing & Preference Grok 4.20 (Non-Reasoning) leads
GPT-6 Luna: 58.4 (#115), Grok 4.20 (Non-Reasoning): 65.9 (#42)
| Benchmark | GPT-6 Luna | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Text | 1392 | 1451 |
| LMArena Creative Writing | 1357 | 1439 |
| LMArena Multi-Turn | 1400 | 1456 |
| EQ-Bench Creative Writing | — | 1574 |
Frequently asked questions
Is GPT-6 Luna better than Grok 4.20 (Non-Reasoning)?
Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.5 to 45.1 on the Noometry Index. GPT-6 Luna costs 7.8× less per token, which makes it the better buy when Grok 4.20 (Non-Reasoning)'s lead doesn't matter for your workload.
Which is cheaper, GPT-6 Luna or Grok 4.20 (Non-Reasoning)?
GPT-6 Luna is cheaper. It lists at $0.10 per million input tokens and $0.50 per million output tokens; Grok 4.20 (Non-Reasoning) lists at $1.25 and $2.50.
Is GPT-6 Luna or Grok 4.20 (Non-Reasoning) better for coding?
GPT-6 Luna scores higher on coding benchmarks: 54.7 versus 41.8 in the Noometry coding category.
Which has the bigger context window?
GPT-6 Luna does, with 1.05M tokens against 1M.
How many benchmarks do GPT-6 Luna and Grok 4.20 (Non-Reasoning) share?
15 benchmarks have published results for both models. GPT-6 Luna has 18 scored results on Noometry and Grok 4.20 (Non-Reasoning) has 46.