Noometry

Model comparison

GPT-6 Luna vs Mercury 2

GPT-6 Luna is the stronger model overall, scoring 53.3 to 39.1 on the Noometry Index.

Last verified . 15 shared benchmarks.

GPT-6 Luna OpenAI

53.3

Rank #36 Confirmed

Mercury 2 Inception

39.1

Rank #175 Confirmed

Summary

  • They share 15 benchmarks with published results for both. GPT-6 Luna scores higher in 7 categories and Mercury 2 in 0 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-6 Luna leads 48.2 to 23.8.
  • The biggest single-benchmark swing is CritPt: 19.4% for GPT-6 Luna and 0.8% for Mercury 2.
  • GPT-6 Luna is cheaper at $0.10 / $0.50 per million input/output tokens, against $0.25 / $0.75 for Mercury 2.
  • GPT-6 Luna accepts more context: 1.05M tokens versus 128K.

Side by side

GPT-6 LunaMercury 2
ProviderOpenAIInception
Noometry Index53.339.1
Released2026-09-222026-02-20
WeightsProprietaryProprietary
Context window1.05M128K
Max output128K50K
Input $ / M tokens$0.10$0.25
Output $ / M tokens$0.50$0.75
Results tracked4217

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Category by category

Coding GPT-6 Luna leads

GPT-6 Luna: 55.5 (#25), Mercury 2: 33.5 (#255)

BenchmarkGPT-6 LunaMercury 2
LMArena WebDev15811171
SciCode54.6%38.7%
LMArena Coding14391391
ALE-Bench1,577785.58
DeepSWE66.6%—
FrontierCode42.4%—
WeirdML—43.2%

Agentic & Tool Use Not comparable

GPT-6 Luna: 33.3 (#54), Mercury 2: —

BenchmarkGPT-6 LunaMercury 2
APEX-Agents44.3%—
GDP.pdf23%—

Reasoning GPT-6 Luna leads

GPT-6 Luna: 48.2 (#41), Mercury 2: 23.8 (#170)

BenchmarkGPT-6 LunaMercury 2
CritPt19.4%0.8%
LMArena Hard Prompts14111362
ARC-AGI-259.3%—
NYT Connections (extended)68.7%—
ARC-AGI-186.7%—
Chess Puzzles31%—
Mystery Game Puzzles7%—
DTBench90.1%—
LMCA44.5%—
Epoch Capabilities Index156.28—

Math Not comparable

GPT-6 Luna: 76.1 (#15), Mercury 2: —

BenchmarkGPT-6 LunaMercury 2
FrontierMath (Tiers 1-3)78.9%—
FrontierMath Tier 456.1%—
OTIS Mock AIME 2024-202598.9%—
ProofBench64%—
LMArena Math1416—

Knowledge GPT-6 Luna leads

GPT-6 Luna: 57.0 (#41), Mercury 2: 36.2 (#172)

BenchmarkGPT-6 LunaMercury 2
LMArena Expert14441358
GPQA Diamond90.5%—
SimpleQA Verified41.4%—
Vectara Hallucination Rate—12.3%

Multimodal Not comparable

GPT-6 Luna: 42.4 (#30), Mercury 2: —

BenchmarkGPT-6 LunaMercury 2
LMArena Vision1217—
Blueprint-Bench 231.2%—
Furniture Assembly44.2%—

Multilingual GPT-6 Luna leads

GPT-6 Luna: 50.5 (#117), Mercury 2: 46.6 (#157)

BenchmarkGPT-6 LunaMercury 2
LMArena Non-English13861331
LMArena Chinese14331417
LMArena Russian13941304
LMArena French1420—
LMArena German1369—
LMArena Japanese1369—
LMArena Korean1360—
LMArena Spanish1393—

Instruction Following GPT-6 Luna leads

GPT-6 Luna: 74.3 (#99), Mercury 2: 70.2 (#165)

BenchmarkGPT-6 LunaMercury 2
LMArena Instruction Following14091329

Long Context GPT-6 Luna leads

GPT-6 Luna: 43.0 (#111), Mercury 2: 40.5 (#154)

BenchmarkGPT-6 LunaMercury 2
LMArena Longer Query14091330

Writing & Preference GPT-6 Luna leads

GPT-6 Luna: 58.3 (#119), Mercury 2: 53.8 (#155)

BenchmarkGPT-6 LunaMercury 2
LMArena Text13911355
LMArena Creative Writing13631289
LMArena Multi-Turn13961358

Frequently asked questions

Is GPT-6 Luna better than Mercury 2?

GPT-6 Luna is the stronger model overall, scoring 53.3 to 39.1 on the Noometry Index.

Which is cheaper, GPT-6 Luna or Mercury 2?

GPT-6 Luna is cheaper. It lists at $0.10 per million input tokens and $0.50 per million output tokens; Mercury 2 lists at $0.25 and $0.75.

Is GPT-6 Luna or Mercury 2 better for coding?

GPT-6 Luna scores higher on coding benchmarks: 55.5 versus 33.5 in the Noometry coding category.

Which has the bigger context window?

GPT-6 Luna does, with 1.05M tokens against 128K.

How many benchmarks do GPT-6 Luna and Mercury 2 share?

15 benchmarks have published results for both models. GPT-6 Luna has 42 scored results on Noometry and Mercury 2 has 17.

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