Noometry

Model comparison

Gemini 3.5 Flash vs GPT-5.1-Codex-mini

Gemini 3.5 Flash has enough public results to be ranked (#32); GPT-5.1-Codex-mini does not yet, so treat this comparison as directional.

Last verified . 1 shared benchmarks.

Gemini 3.5 Flash Google

54.2

Rank #32 Confirmed

GPT-5.1-Codex-mini OpenAI

37.3

Unranked Sparse

Summary

  • They share 1 benchmark with published results for both. Gemini 3.5 Flash scores higher in 1 category and GPT-5.1-Codex-mini in 1 category; 2 gaps are clear of the uncertainty.
  • The widest gap is in coding, where Gemini 3.5 Flash leads 49.4 to 31.6.
  • GPT-5.1-Codex-mini is cheaper at $0.25 / $2 per million input/output tokens, against $1.50 / $9 for Gemini 3.5 Flash.
  • Gemini 3.5 Flash accepts more context: 1.05M tokens versus 400K.

Side by side

Gemini 3.5 FlashGPT-5.1-Codex-mini
ProviderGoogleOpenAI
Noometry Index54.237.3
Released2026-05-192025-11-12
WeightsProprietaryProprietary
Context window1.05M400K
Max output66K128K
Input $ / M tokens$1.50$0.25
Output $ / M tokens$9$2
Results tracked542

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Category by category

Coding Gemini 3.5 Flash leads

Gemini 3.5 Flash: 49.4 (#49), GPT-5.1-Codex-mini: 31.6

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
LMArena WebDev14991244
SWE-bench Verified79.3%—
DeepSWE37.4%—
SciCode53.1%—
WeirdML62.6%—
LMArena Coding1492—
ALE-Bench911.02—

Agentic & Tool Use GPT-5.1-Codex-mini leads

Gemini 3.5 Flash: 24.7 (#114), GPT-5.1-Codex-mini: 38.5

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
Terminal-Bench—61.6%
APEX-Agents27.5%—
GBAEval6.7%—
GDP.pdf14%—
Vending-Bench 25,396—

Reasoning Not comparable

Gemini 3.5 Flash: 62.8 (#18), GPT-5.1-Codex-mini: —

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
ARC-AGI-272.1%—
SimpleBench76.7%—
NYT Connections (extended)92.6%—
ARC-AGI-192.5%—
CritPt13.1%—
Chess Puzzles50%—
EnigmaEval25.4%—
EBR-Bench4.8%—
LMArena Hard Prompts1488—
Mystery Game Puzzles32%—
DTBench94.7%—
LMCA47.1%—
Surface Evolver Bench58.1%—
Epoch Capabilities Index154.46—
ForecastBench59—

Math Not comparable

Gemini 3.5 Flash: 60.7 (#36), GPT-5.1-Codex-mini: —

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
FrontierMath (Tiers 1-3)62.8%—
FrontierMath Tier 426.8%—
MathArena Final-Answer Competitions76.3%—
OTIS Mock AIME 2024-202595.6%—
ProofBench31%—
LMArena Math1504—
FrontierMath (Feb 2025 set)39%—
FrontierMath Tier 4 (v1)14.6%—

Knowledge Not comparable

Gemini 3.5 Flash: 66.3 (#11), GPT-5.1-Codex-mini: —

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
GPQA Diamond92.8%—
SimpleQA Verified66.2%—
LMArena Expert1495—

Multimodal Not comparable

Gemini 3.5 Flash: 45.7 (#15), GPT-5.1-Codex-mini: —

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
LMArena Vision1310—
Blueprint-Bench 233.6%—
LMArena Document1463—

Multilingual Not comparable

Gemini 3.5 Flash: 57.0 (#13), GPT-5.1-Codex-mini: —

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
LMArena Non-English1476—
LMArena Chinese1526—
LMArena French1490—
LMArena German1492—
LMArena Japanese1486—
LMArena Korean1451—
LMArena Russian1493—
LMArena Spanish1480—

Instruction Following Not comparable

Gemini 3.5 Flash: 77.0 (#30), GPT-5.1-Codex-mini: —

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
LMArena Instruction Following1467—

Long Context Not comparable

Gemini 3.5 Flash: 45.4 (#38), GPT-5.1-Codex-mini: —

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
LMArena Longer Query1482—

Writing & Preference Not comparable

Gemini 3.5 Flash: 65.5 (#47), GPT-5.1-Codex-mini: —

BenchmarkGemini 3.5 FlashGPT-5.1-Codex-mini
LMArena Text1482—
LMArena Creative Writing1470—
EQ-Bench 41087—
LMArena Multi-Turn1481—

Frequently asked questions

Is Gemini 3.5 Flash better than GPT-5.1-Codex-mini?

Gemini 3.5 Flash has enough public results to be ranked (#32); GPT-5.1-Codex-mini does not yet, so treat this comparison as directional.

Which is cheaper, Gemini 3.5 Flash or GPT-5.1-Codex-mini?

GPT-5.1-Codex-mini is cheaper. It lists at $0.25 per million input tokens and $2 per million output tokens; Gemini 3.5 Flash lists at $1.50 and $9.

Is Gemini 3.5 Flash or GPT-5.1-Codex-mini better for coding?

Gemini 3.5 Flash scores higher on coding benchmarks: 49.4 versus 31.6 in the Noometry coding category.

Which has the bigger context window?

Gemini 3.5 Flash does, with 1.05M tokens against 400K.

How many benchmarks do Gemini 3.5 Flash and GPT-5.1-Codex-mini share?

1 benchmark has published results for both models. Gemini 3.5 Flash has 54 scored results on Noometry and GPT-5.1-Codex-mini has 2.

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