Model comparison

GPT-5.6 Luna vs Mistral Small

GPT-5.6 Luna is the stronger model overall, scoring 54.6 to 33.4 on the Noometry Index. Mistral Small costs 1.7× less per token, which makes it the better buy when GPT-5.6 Luna's lead doesn't matter for your workload.

Last verified . 26 shared benchmarks.

GPT-5.6 Luna OpenAI

54.6

Rank #30 Confirmed

Mistral Small Mistral AI

33.4

Rank #243 Confirmed

Summary

  • They share 26 benchmarks with published results for both. GPT-5.6 Luna scores higher in 10 categories and Mistral Small in 0 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Luna leads 77.7 to 16.4.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 98.3% for GPT-5.6 Luna and 5.8% for Mistral Small.
  • Mistral Small is cheaper at $0.15 / $0.60 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.
  • Mistral Small has downloadable open weights; the other is API-only.

Side by side

GPT-5.6 Luna and Mistral Small specifications
GPT-5.6 LunaMistral Small
ProviderOpenAIMistral AI
Noometry Index54.633.4
Released2026-07-092024-02-26
WeightsProprietaryOpen
Context window1.05M262K
Max output128K256K
Input $ / M tokens$0.20$0.15
Output $ / M tokens$1.20$0.60
Results tracked5239

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Category by category

Coding GPT-5.6 Luna leads

GPT-5.6 Luna: 54.5 (#28), Mistral Small: 34.0 (#247)

Coding benchmarks
BenchmarkGPT-5.6 LunaMistral Small
SciCode53.6%26.5%
LMArena Coding14661362
ALE-Bench1,667497.62
DeepSWE67.2%—
FrontierCode39.8%—
CursorBench35.9%—
LMArena WebDev1519—
WeirdML60.9%—
BigCodeBench Instruct—36.1%
LiveBench Coding—36.2%
BigCodeBench Complete—46.6%

Agentic & Tool Use GPT-5.6 Luna leads

GPT-5.6 Luna: 34.4 (#45), Mistral Small: 28.1 (#93)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 LunaMistral Small
APEX-Agents43%—
Berkeley Function Calling Leaderboard—37.1%
BALROG45.6%—
GDP.pdf22.7%—
Vending-Bench 24,095—

Reasoning GPT-5.6 Luna leads

GPT-5.6 Luna: 47.6 (#43), Mistral Small: 19.8 (#250)

Reasoning benchmarks
BenchmarkGPT-5.6 LunaMistral Small
Kagi LLM Benchmark49.1%37.8%
CritPt20.6%0%
LMArena Hard Prompts14511335
DTBench89.1%70.9%
LMCA48.5%20.6%
ARC-AGI-259.5%—
SimpleBench46.8%—
NYT Connections (extended)69.4%—
ARC-AGI-188%—
Chess Puzzles40%—
LiveBench Reasoning—44.8%
Mystery Game Puzzles21%—
LiveBench Data Analysis—53.7%
Surface Evolver Bench61.9%—
Epoch Capabilities Index156.39—
LiveBench—44%

Math GPT-5.6 Luna leads

GPT-5.6 Luna: 77.7 (#14), Mistral Small: 16.4 (#293)

Math benchmarks
BenchmarkGPT-5.6 LunaMistral Small
OTIS Mock AIME 2024-202598.3%5.8%
LMArena Math14581341
FrontierMath (Tiers 1-3)82.1%—
FrontierMath Tier 461%—
ProofBench60%—
LiveBench Math—39.9%
MATH Level 5—46.8%

Knowledge GPT-5.6 Luna leads

GPT-5.6 Luna: 58.5 (#34), Mistral Small: 31.0 (#222)

Knowledge benchmarks
BenchmarkGPT-5.6 LunaMistral Small
GPQA Diamond91.6%47.5%
LMArena Expert14781291
SimpleQA Verified41%—
Vectara Hallucination Rate—5.1%
MMLU—68.7%

Multimodal GPT-5.6 Luna leads

GPT-5.6 Luna: 42.7 (#28), Mistral Small: 33.5 (#96)

Multimodal benchmarks
BenchmarkGPT-5.6 LunaMistral Small
LMArena Vision12581142
Blueprint-Bench 222.6%—
Furniture Assembly42.5%—
LMArena Document1457—

Multilingual GPT-5.6 Luna leads

GPT-5.6 Luna: 52.8 (#78), Mistral Small: 45.5 (#169)

Multilingual benchmarks
BenchmarkGPT-5.6 LunaMistral Small
LMArena Non-English14171315
LMArena Chinese14701340
LMArena French14561337
LMArena German14541340
LMArena Japanese14111275
LMArena Korean14151259
LMArena Russian14281324
LMArena Spanish14481346

Instruction Following GPT-5.6 Luna leads

GPT-5.6 Luna: 75.6 (#57), Mistral Small: 66.4 (#209)

Instruction Following benchmarks
BenchmarkGPT-5.6 LunaMistral Small
LMArena Instruction Following14371310
LiveBench Instruction Following—63.7%

Long Context GPT-5.6 Luna leads

GPT-5.6 Luna: 43.9 (#82), Mistral Small: 40.4 (#156)

Long Context benchmarks
BenchmarkGPT-5.6 LunaMistral Small
LMArena Longer Query14361327

Writing & Preference GPT-5.6 Luna leads

GPT-5.6 Luna: 68.0 (#29), Mistral Small: 52.5 (#171)

Writing & Preference benchmarks
BenchmarkGPT-5.6 LunaMistral Small
LMArena Text14311338
LMArena Creative Writing13961305
LMArena Multi-Turn14341344
EQ-Bench Creative Writing1829—
EQ-Bench 41156—
LiveBench Language—30.5%

Frequently asked questions

Is GPT-5.6 Luna better than Mistral Small?

GPT-5.6 Luna is the stronger model overall, scoring 54.6 to 33.4 on the Noometry Index. Mistral Small costs 1.7× 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, GPT-5.6 Luna or Mistral Small?

Mistral Small is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; GPT-5.6 Luna lists at $0.20 and $1.20.

Is GPT-5.6 Luna or Mistral Small better for coding?

GPT-5.6 Luna scores higher on coding benchmarks: 54.5 versus 34.0 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 GPT-5.6 Luna and Mistral Small share?

26 benchmarks have published results for both models. GPT-5.6 Luna has 52 scored results on Noometry and Mistral Small has 39.

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