Model comparison

Gemma 4 31B IT vs GPT-5.6 Luna

GPT-5.6 Luna is the stronger model overall, scoring 54.6 to 43.5 on the Noometry Index. Gemma 4 31B IT costs 3.0× less per token, which makes it the better buy when GPT-5.6 Luna's lead doesn't matter for your workload.

Last verified . 33 shared benchmarks.

Gemma 4 31B IT Google

43.5

Rank #90 Confirmed

GPT-5.6 Luna OpenAI

54.6

Rank #30 Confirmed

Summary

  • They share 33 benchmarks with published results for both. Gemma 4 31B IT scores higher in 2 categories and GPT-5.6 Luna in 7 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Luna leads 77.7 to 43.2.
  • The biggest single-benchmark swing is Chess Puzzles: 5% for Gemma 4 31B IT and 40% for GPT-5.6 Luna.
  • Gemma 4 31B IT is cheaper at $0.09 / $0.34 per million input/output tokens, against $0.20 / $1.20 for GPT-5.6 Luna.
  • GPT-5.6 Luna accepts more context: 1.05M tokens versus 262K.
  • Gemma 4 31B IT has downloadable open weights; the other is API-only.

Side by side

Gemma 4 31B IT and GPT-5.6 Luna specifications
Gemma 4 31B ITGPT-5.6 Luna
ProviderGoogleOpenAI
Noometry Index43.554.6
Released2026-04-022026-07-09
WeightsOpenProprietary
Context window262K1.05M
Max output33K128K
Input $ / M tokens$0.09$0.20
Output $ / M tokens$0.34$1.20
Results tracked3552

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Category by category

Coding GPT-5.6 Luna leads

Gemma 4 31B IT: 42.3 (#108), GPT-5.6 Luna: 54.5 (#28)

Coding benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
LMArena WebDev13661519
SciCode43.4%53.6%
WeirdML52.3%60.9%
LMArena Coding14591466
ALE-Bench925.51,667
DeepSWE—67.2%
FrontierCode—39.8%
CursorBench—35.9%

Agentic & Tool Use Not comparable

Gemma 4 31B IT: —, GPT-5.6 Luna: 34.4 (#45)

Agentic & Tool Use benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
APEX-Agents—43%
BALROG—45.6%
GDP.pdf—22.7%
Vending-Bench 2—4,095

Reasoning GPT-5.6 Luna leads

Gemma 4 31B IT: 27.2 (#122), GPT-5.6 Luna: 47.6 (#43)

Reasoning benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
Kagi LLM Benchmark63.5%49.1%
NYT Connections (extended)70.6%69.4%
CritPt1.4%20.6%
Chess Puzzles5%40%
LMArena Hard Prompts14481451
DTBench82.7%89.1%
LMCA39.3%48.5%
Surface Evolver Bench30.6%61.9%
Epoch Capabilities Index142.74156.39
ARC-AGI-2—59.5%
SimpleBench—46.8%
ARC-AGI-1—88%
Thematic Generalization53%—
Mystery Game Puzzles—21%

Math GPT-5.6 Luna leads

Gemma 4 31B IT: 43.2 (#81), GPT-5.6 Luna: 77.7 (#14)

Math benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
OTIS Mock AIME 2024-202573.3%98.3%
LMArena Math14651458
FrontierMath (Tiers 1-3)—82.1%
FrontierMath Tier 4—61%
ProofBench—60%

Knowledge GPT-5.6 Luna leads

Gemma 4 31B IT: 37.9 (#151), GPT-5.6 Luna: 58.5 (#34)

Knowledge benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
GPQA Diamond75.8%91.6%
SimpleQA Verified10.4%41%
LMArena Expert14651478
Vectara Hallucination Rate7.4%—

Multimodal GPT-5.6 Luna leads

Gemma 4 31B IT: 41.6 (#34), GPT-5.6 Luna: 42.7 (#28)

Multimodal benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
LMArena Vision12771258
LMArena Document14251457
Blueprint-Bench 2—22.6%
Furniture Assembly—42.5%

Multilingual Gemma 4 31B IT leads

Gemma 4 31B IT: 53.8 (#57), GPT-5.6 Luna: 52.8 (#78)

Multilingual benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
LMArena Non-English14311417
LMArena Chinese14761470
LMArena French14351456
LMArena Russian14601428
LMArena Spanish14441448
LMArena German—1454
LMArena Japanese—1411
LMArena Korean—1415

Instruction Following Too close to call

Gemma 4 31B IT: 75.5 (#61), GPT-5.6 Luna: 75.6 (#57)

Instruction Following benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
LMArena Instruction Following14331437

Long Context Too close to call

Gemma 4 31B IT: 44.2 (#71), GPT-5.6 Luna: 43.9 (#82)

Long Context benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
LMArena Longer Query14461436

Writing & Preference GPT-5.6 Luna leads

Gemma 4 31B IT: 60.5 (#96), GPT-5.6 Luna: 68.0 (#29)

Writing & Preference benchmarks
BenchmarkGemma 4 31B ITGPT-5.6 Luna
LMArena Text14431431
LMArena Creative Writing14151396
EQ-Bench Creative Writing13681829
EQ-Bench 411201156
LMArena Multi-Turn14521434

Frequently asked questions

Is Gemma 4 31B IT better than GPT-5.6 Luna?

GPT-5.6 Luna is the stronger model overall, scoring 54.6 to 43.5 on the Noometry Index. Gemma 4 31B IT costs 3.0× less per token, which makes it the better buy when GPT-5.6 Luna's lead doesn't matter for your workload.

Which is cheaper, Gemma 4 31B IT or GPT-5.6 Luna?

Gemma 4 31B IT is cheaper. It lists at $0.09 per million input tokens and $0.34 per million output tokens; GPT-5.6 Luna lists at $0.20 and $1.20.

Is Gemma 4 31B IT or GPT-5.6 Luna better for coding?

GPT-5.6 Luna scores higher on coding benchmarks: 54.5 versus 42.3 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Luna does, with 1.05M tokens against 262K.

How many benchmarks do Gemma 4 31B IT and GPT-5.6 Luna share?

33 benchmarks have published results for both models. Gemma 4 31B IT has 35 scored results on Noometry and GPT-5.6 Luna has 52.

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