Compare / head-to-head
GPT-5.2-CodexvsGPT-6 Luna
GPT-6 Luna leads 5 of 8 shared benchmarks. GPT-6 Luna is 26.3x cheaper per token. GPT-6 Luna has the larger context window (1.1M tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
3 – 5
GPT-6 Luna leads
Cheaper per token
GPT-6 Luna
26.3x cheaper, input + output
Larger context
GPT-6 Luna
1.1M tokens
Providers
OpenAI
same provider
GPT-5.2-Codex
OpenAI · released 2025-12-18
textvision
GPT-6 Luna
OpenAI · released 2026-09-22
textvision
Quality
Benchmark matrix
8 shared · 5 only GPT-5.2-Codex · 14 only GPT-6 Luna| Benchmark | GPT-5.2-Codex | GPT-6 Luna | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 8 | ||||
| LiveBench Agentic Coding (LiveBench) | 49.4% ↗ | 51.2% ↗ | -1.8 pt | GPT-6 Luna |
| LiveBench Coding (LiveBench) | 83.6% ↗ | 79% ↗ | +4.6 pt | GPT-5.2-Codex |
| LiveBench Data Analysis (LiveBench) | 78.2% ↗ | 73.4% ↗ | +4.8 pt | GPT-5.2-Codex |
| LiveBench Instruction Following (LiveBench) | 66.4% ↗ | 55.9% ↗ | +10.5 pt | GPT-5.2-Codex |
| LiveBench Language (LiveBench) | 73.7% ↗ | 73.8% ↗ | -0.1 pt | GPT-6 Luna |
| LiveBench Mathematics (LiveBench) | 88.8% ↗ | 89.1% ↗ | -0.3 pt | GPT-6 Luna |
| LiveBench Reasoning (LiveBench) | 77.7% ↗ | 81.8% ↗ | -4.1 pt | GPT-6 Luna |
| LMArena WebDev (LMArena) | 1338.9 ↗ | 1578.7 ↗ | -239.8 | GPT-6 Luna |
| Only GPT-5.2-Codex reports · 5 | ||||
| Cybersecurity Capture The Flag Challenges | 67.4% ↗ | not reported | — | — |
| OSWorld-Verified | 38.2% ↗ | not reported | — | — |
| SWE-Bench Pro | 56.4% ↗ | not reported | — | — |
| SWE-Lancer IC Diamond | 76% ↗ | not reported | — | — |
| Terminal-Bench 2.0 | 64% ↗ | not reported | — | — |
| Only GPT-6 Luna reports · 14 | ||||
| GPQA Diamond | not reported | 90.5% ↗epoch run | — | — |
| LMArena Elo | not reported | 1442.9 ↗ | — | — |
| APEX-Agents (Mercor) | not reported | 44.3% ↗ | — | — |
| Chess Puzzles (Epoch AI run) | not reported | 31% ↗epoch run | — | — |
| DeepSWE v1.1 | not reported | 66.6% ↗ | — | — |
| FrontierMath Tier 4 v2 (Epoch AI run) | not reported | 56.1% ↗epoch run | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | not reported | 78.9% ↗epoch run | — | — |
| Furniture Assembly (Epoch AI run) | not reported | 44.2% ↗epoch run | — | — |
| LMArena Agent (LMArena) | not reported | 0.0135 ↗ | — | — |
| Mystery Game Puzzles (Epoch AI run) | not reported | 7% ↗epoch run | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | not reported | 98.9% ↗epoch run | — | — |
| SAGE (Vals AI) | not reported | 48.1% ↗ | — | — |
| SimpleQA Verified | not reported | 41.4% ↗epoch run | — | — |
| Terminal-Bench 4.0 (Vals AI) | not reported | 13.6% ↗ | — | — |
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-5.2-Codex minus GPT-6 Luna 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-5.2-Codex | GPT-6 Luna | Edge |
|---|---|---|---|
| Context window | 400K tokens | 1.1M tokens | GPT-6 Luna |
| Max output | 128K tokens | 128K tokens | Tie |
| Input price / 1M | $1.75 ↗ | $0.1 ↗ | GPT-6 Luna |
| Output price / 1M | $14 ↗ | $0.5 ↗ | GPT-6 Luna |
| Cached input / 1M | $0.175 ↗ | $0.01 ↗ | GPT-6 Luna |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $15.75 | $0.6 | GPT-6 Luna |
| Modalities | text · vision | text · vision | Tie |
| Released | 2025-12-18 | 2026-09-22 | — |
| Cited benchmark scores | 13 | 22 | — |
Reliability
OpenAI status
Live from /statusMore matchups
GPT-5.2-Codex vs …
Models sharing the most benchmarksMore matchups
GPT-6 Luna vs …
Models sharing the most benchmarksBuilt by Respan
Which one wins on your data?
Public benchmarks are a starting point. Run GPT-5.2-Codex and GPT-6 Luna on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.