Compare / head-to-head
GPT-6 Lunavs
Grok 4.1 Fast Reasoning
GPT-6 Luna leads 3 of 3 shared benchmarks. GPT-6 Luna is 1.2x cheaper per token. Grok 4.1 Fast Reasoning has the larger context window (2M tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
3 – 0
GPT-6 Luna leads
Cheaper per token
GPT-6 Luna
1.2x cheaper, input + output
Larger context
Grok 4.1 Fast Reasoning
2M tokens
Providers
2 providers
OpenAI · xAI
GPT-6 Luna
OpenAI · released 2026-09-22
textvision
Grok 4.1 Fast Reasoning
xAI · released 2025-11-19
text
Quality
Benchmark matrix
3 shared · 19 only GPT-6 Luna · 4 only Grok 4.1 Fast Reasoning| Benchmark | GPT-6 Luna | Grok 4.1 Fast Reasoning | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 3 | ||||
| LMArena Elo | 1442.9 ↗ | 1430.3 ↗ | +12.6 | GPT-6 Luna |
| LMArena WebDev (LMArena) | 1578.7 ↗ | 1241.3 ↗ | +337.4 | GPT-6 Luna |
| SAGE (Vals AI) | 48.1% ↗ | 31.3% ↗ | +16.8 pt | GPT-6 Luna |
| Only GPT-6 Luna reports · 19 | ||||
| GPQA Diamond | 90.5% ↗epoch run | not reported | — | — |
| APEX-Agents (Mercor) | 44.3% ↗ | not reported | — | — |
| Chess Puzzles (Epoch AI run) | 31% ↗epoch run | not reported | — | — |
| DeepSWE v1.1 | 66.6% ↗ | not reported | — | — |
| FrontierMath Tier 4 v2 (Epoch AI run) | 56.1% ↗epoch run | not reported | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | 78.9% ↗epoch run | not reported | — | — |
| Furniture Assembly (Epoch AI run) | 44.2% ↗epoch run | not reported | — | — |
| LiveBench Agentic Coding (LiveBench) | 51.2% ↗ | not reported | — | — |
| LiveBench Coding (LiveBench) | 79% ↗ | not reported | — | — |
| LiveBench Data Analysis (LiveBench) | 73.4% ↗ | not reported | — | — |
| LiveBench Instruction Following (LiveBench) | 55.9% ↗ | not reported | — | — |
| LiveBench Language (LiveBench) | 73.8% ↗ | not reported | — | — |
| LiveBench Mathematics (LiveBench) | 89.1% ↗ | not reported | — | — |
| LiveBench Reasoning (LiveBench) | 81.8% ↗ | not reported | — | — |
| LMArena Agent (LMArena) | 0.0135 ↗ | not reported | — | — |
| Mystery Game Puzzles (Epoch AI run) | 7% ↗epoch run | not reported | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 98.9% ↗epoch run | not reported | — | — |
| SimpleQA Verified | 41.4% ↗epoch run | not reported | — | — |
| Terminal-Bench 4.0 (Vals AI) | 13.6% ↗ | not reported | — | — |
| Only Grok 4.1 Fast Reasoning reports · 4 | ||||
| FRAMES (Agent Tools API) | not reported | 87.6% ↗ | — | — |
| LMArena Vision (LMArena) | not reported | 1196.3 ↗ | — | — |
| Research-Eval Reka (Agent Tools API) | not reported | 63.9% ↗ | — | — |
| Vending-Bench 2 (Andon Labs) | not reported | 1106.63 ↗ | — | — |
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is GPT-6 Luna minus Grok 4.1 Fast Reasoning in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | GPT-6 Luna | Grok 4.1 Fast Reasoning | Edge |
|---|---|---|---|
| Context window | 1.1M tokens | 2M tokens | Grok 4.1 Fast Reasoning |
| Max output | 128K tokens | — | — |
| Input price / 1M | $0.1 ↗ | $0.2 ↗ | GPT-6 Luna |
| Output price / 1M | $0.5 ↗ | $0.5 ↗ | Tie |
| Cached input / 1M | $0.01 ↗ | $0.05 ↗ | GPT-6 Luna |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $0.6 | $0.7 | GPT-6 Luna |
| Modalities | text · vision | text | GPT-6 Luna |
| Released | 2026-09-22 | 2025-11-19 | — |
| Cited benchmark scores | 22 | 7 | — |
Reliability
Provider status
Live from /statusMore matchups
GPT-6 Luna vs …
Models sharing the most benchmarksMore matchups
Grok 4.1 Fast Reasoning vs …
Models sharing the most benchmarksBuilt by Respan
Which one wins on your data?
Public benchmarks are a starting point. Run GPT-6 Luna and Grok 4.1 Fast Reasoning on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.